[cfaussie] Re: Strange calculation behavior on CF 7.02
I remember someone raising this issue yonks ago in CF 4.5 or something A quick fix: #round((1024-1024.1)*10)/10# On Wed, 2007-02-21 at 13:38 +1100, Robin Hilliard wrote: What exactly is a 'CF number'? All simple CF variables are stored as strings. When used as numbers in an expression they have 12 significant digits according to the documentation, which I assume is a java Float (a Double would have more). As for a solution in CFML, I wouldn't mind an optional second argument to round(), fix(), ceil() etc that defaulted to 0 and specified the number of decimal places to round to (Excel VBA has this). I imagine that changing the type used to represent numbers internally or building rounding into all number handling may impact legacy cf apps and server performance - I would be against a change if either were true. Cheers, Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 e[EMAIL PROTECTED] or Direct: m+61 418 414 341 e[EMAIL PROTECTED] On 21/02/2007, at 10:32 AM, Rod Higgins wrote: Hi Robin, What exactly is a 'CF number'? It seems to be CF can store it as a string or a double / float depending on the way it is constructed or what methods are used on the var. I agree with Gareth in that CF needs to make untyped numbers in CF more consistent. The values generated from Gareth's code shouldn't happen and no I don't agree with the opinion it is a fault / known issue of the Java language, it is simply the way CF was written to use Java. They decided to go with a smaller memory footprint for storing numeric values. This is a very annoying issue when dealing with very small numbers in CF and has driven me nuts plenty of times before. Obviously using BigDecimal for every numeric in CF would use too much memory but maybe some option for the construction of 'CF numbers' so developers can choose to be more precise. Rod --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Andrew, To say that it has nothing to do with ColdFusion is incorrect - as a developer has come across the issue developing an application using ColdFusion. Sure it is an 'across the board of programming languages' issue - but that doesn't mean that Adobe cannot note the issue in its documentation and training guides - which is what Gareth was suggesting. Robin's suggestion looks to be the neatest solution so far. Steve On 2/20/07, Andrew Scott [EMAIL PROTECTED] wrote: Gareth, Again you have been politely told it has nothing to do with Coldfusion, if you are aware how Coldfusion works under the hood, then accept that it is a know problem not a bug then deal with it and move on. Complaining about CF is not going to change the fact that Java has the issue and not CF. Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 *From:* cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] *On Behalf Of *Gareth Edwards *Sent:* Tuesday, 20 February 2007 2:40 PM *To:* cfaussie@googlegroups.com *Subject:* [cfaussie] Re: Strange calculation behavior on CF 7.02 Indicating you know how Coldfusion works really proves nothing, I'm quite aware of how it all works. I'm just annoyed that Coldfusion doesn't deal with this situation better than it does. Once again, Javascript, although not strictly typed, is a typed language. If I could type in Coldfusion I would. Also, Coldfusion should get this one right, but it doesn't cfdump var=#1024.00-1024.10# returns -0.0 Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Hi Rod, Big Decimal has far more precision than a CF number (only 12 significant digits) and has built in rounding - you can set the precision with it's setScale(scale, rounding-mode) method. One point to note if you are using BigDecimal - you should use the string constructor i.e. init(0.1) because otherwise ColdFusion will convert the literal 0.1 to a ColdFusion number (with it's more limited precision) before passing it to Java. Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 e[EMAIL PROTECTED] or Direct: m+61 418 414 341 e[EMAIL PROTECTED] On 20/02/2007, at 6:43 PM, rod higgins wrote: If you use the java class and methods that handle these types of numbers I don't see the problem?? cfloop from=1 to=1000 index=i cfset diff = CreateObject(Java, java.math.BigDecimal).init(0.1) cfset a = CreateObject(Java, java.math.BigDecimal).init(RandRange(100,1)) cfset b = CreateObject(Java, java.math.BigDecimal).init(a*2) cfset c = CreateObject(Java, java.math.BigDecimal).init(val(a)) cfset c = c.add(diff) cfset d = a.subtract(b).add(c) cfoutput#a#-#b#+#c# = #d#br //cfoutput /cfloop It seems CF is using some sort of toString() value during the calculation at some stage?? hth Rod On Feb 20, 12:04 pm, Gareth Edwards [EMAIL PROTECTED] wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Steve, Gareth stated and I quote, It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. So as you see I am correct by saying it has nothing to do with CF, but yes I agree about some form of docs etc. And to expect CF not to have this problem is where he got our backs up, not that it should have been documented somewhere but his quote says it all. Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Steve Armstrong Sent: Tuesday, 20 February 2007 8:47 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Andrew, To say that it has nothing to do with ColdFusion is incorrect - as a developer has come across the issue developing an application using ColdFusion. Sure it is an 'across the board of programming languages' issue - but that doesn't mean that Adobe cannot note the issue in its documentation and training guides - which is what Gareth was suggesting. Robin's suggestion looks to be the neatest solution so far. Steve --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Hmm, interesting you used to be able to select that option in previous versionJ Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
What exactly is a 'CF number'? All simple CF variables are stored as strings. When used as numbers in an expression they have 12 significant digits according to the documentation, which I assume is a java Float (a Double would have more). As for a solution in CFML, I wouldn't mind an optional second argument to round(), fix(), ceil() etc that defaulted to 0 and specified the number of decimal places to round to (Excel VBA has this). I imagine that changing the type used to represent numbers internally or building rounding into all number handling may impact legacy cf apps and server performance - I would be against a change if either were true. Cheers, Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 e[EMAIL PROTECTED] or Direct: m+61 418 414 341 e[EMAIL PROTECTED] On 21/02/2007, at 10:32 AM, Rod Higgins wrote: Hi Robin, What exactly is a 'CF number'? It seems to be CF can store it as a string or a double / float depending on the way it is constructed or what methods are used on the var. I agree with Gareth in that CF needs to make untyped numbers in CF more consistent. The values generated from Gareth's code shouldn't happen and no I don't agree with the opinion it is a fault / known issue of the Java language, it is simply the way CF was written to use Java. They decided to go with a smaller memory footprint for storing numeric values. This is a very annoying issue when dealing with very small numbers in CF and has driven me nuts plenty of times before. Obviously using BigDecimal for every numeric in CF would use too much memory but maybe some option for the construction of 'CF numbers' so developers can choose to be more precise. Rod --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
LOL, that was sent to the wrong list. Sorry for the confusion. Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Wednesday, 21 February 2007 1:41 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Andrew, What option? Cheers Gareth. Andrew Scott wrote: Hmm, interesting you used to be able to select that option in previous versionJ Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
not having a working CF server handy at the moment to test, I'm just curious you're not getting grief with treating strings as numbers, are you? perhaps a val( #ListFirst(Trim(a),.)#.00 ) is needed? just a quick thought b On 2/20/07, Gareth Edwards [EMAIL PROTECTED] wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
If it were a string, and it was having troubles the end result should be consistent. Check this out. 9314-18628+9314.1 = 0.1 4730-9460+4730.1 = 0.1 9913-19826+9913.1 = 0.1 3913-7826+3913.1 = 0.0 6770-13540+6770.1 = 0.1 3000-6000+3000.1 = 0.0 Cheers Gareth. Barry Beattie wrote: not having a working CF server handy at the moment to test, I'm just curious you're not getting grief with treating strings as numbers, are you? perhaps a val( "#ListFirst(Trim(a),".")#.00" ) is needed? just a quick thought b On 2/20/07, Gareth Edwards [EMAIL PROTECTED] wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from="1" to="1000" index="i" cfset a = RandRange(1,2) cfset b = a*2 cfset c = "#ListFirst(Trim(a),".")#.00" cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Just an update... the new code below does the same thing.
cfset a = 0
cfset b = 0
cfset c = 0
cfloop from="1" to="1000" index="i"
cfset a = RandRange(100,1)
cfset b = a*2
cfset c = val("#ListFirst(Trim(a),".")#.00")
cfset c = c + 0.1
cfset d = a - b + c
cfoutput#a#-#b#+#c# = #d#br //cfoutput
/cfloop
Barry Beattie wrote:
not having a working CF server handy at the moment to test, I'm just curious
you're not getting grief with treating strings as numbers, are you?
perhaps a val( "#ListFirst(Trim(a),".")#.00" ) is needed?
just a quick thought
b
On 2/20/07, Gareth Edwards [EMAIL PROTECTED] wrote:
If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know)
Run this script below, and tell me if you get the same results for each
line. The way I see it, d should equal 0.1 on every row. But this isn't
the case. Is this a bug introduced by Coldfusion 7.02?
cfset a = 0
cfset b = 0
cfset c = 0
cfloop from="1" to="1000" index="i"
cfset a = RandRange(1,2)
cfset b = a*2
cfset c = "#ListFirst(Trim(a),".")#.00"
cfset c = c + 0.1
cfset d = a - val(b) + val(c)
cfoutput#d#br //cfoutput
/cfloop
Cheers
Gareth.
--~--~-~--~~~---~--~~
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[cfaussie] Re: Strange calculation behavior on CF 7.02
They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. Cheers Gareth. Ryan Sabir wrote: They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from="1" to="1000" index="i" cfset a = RandRange(1,2) cfset b = a*2 cfset c = "#ListFirst(Trim(a),".")#.00" cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
I just tried it on an old CF5 server and it did the same thing. It's nothing to do with data typing. The underlying calculation to work out what X * 0.1 is, will always have some degree of rounding error due to the way those numbers are stored in memory. From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:37 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. Cheers Gareth. Ryan Sabir wrote: They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
What about 7.01 or 7.00? or 6.1 or 6? CF5 is not a fair comparison. Cheers Gareth. Ryan Sabir wrote: I just tried it on anold CF5 server and it did the same thing. It's nothing to do with data typing. The underlying calculation to work out whatX * 0.1 is, will always have some degree of rounding error due to the way those numbers are stored in memory. From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:37 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. Cheers Gareth. Ryan Sabir wrote: They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from="1" to="1000" index="i" cfset a = RandRange(1,2) cfset b = a*2 cfset c = "#ListFirst(Trim(a),".")#.00" cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
AFAIK this has always been an issue. I usually deal with it by using integers where possible, as in store and calculate prices in cents not dollars - don't have much call for anything more complicated than that. B) Gareth Edwards wrote: What about 7.01 or 7.00? or 6.1 or 6? CF5 is not a fair comparison. Cheers Gareth. Ryan Sabir wrote: I just tried it on an old CF5 server and it did the same thing. It's nothing to do with data typing. The underlying calculation to work out what X * 0.1 is, will always have some degree of rounding error due to the way those numbers are stored in memory. *From:* cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] *On Behalf Of *Gareth Edwards *Sent:* Tuesday, 20 February 2007 12:37 PM *To:* cfaussie@googlegroups.com *Subject:* [cfaussie] Re: Strange calculation behavior on CF 7.02 It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. Cheers Gareth. Ryan Sabir wrote: They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Just remembered I had a 6.1 server lying around. And yes it did the same thing: 0.1 0.1 0.1 0.09985 0.09985 0.1 0.09985 0.1 0.1 0.09985 0.1 0.09985 0.09985 0.09985 0.1 0.1 0.1 0.1 0.09985 0.1 There's lots of references to this common problem, e.g.: http://www.regdeveloper.co.uk/2006/08/12/floating_point_approximation/ As to why you are seeing different results in different CF versions... not sure. But if you code to expect the rounding errors, then it won't matter. From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:53 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 What about 7.01 or 7.00? or 6.1 or 6? CF5 is not a fair comparison. Cheers Gareth. Ryan Sabir wrote: I just tried it on an old CF5 server and it did the same thing. It's nothing to do with data typing. The underlying calculation to work out what X * 0.1 is, will always have some degree of rounding error due to the way those numbers are stored in memory. From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:37 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. Cheers Gareth. Ryan Sabir wrote: They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
So why the mixed result? Cheers Gareth. Ryan Sabir wrote: Just remembered I had a 6.1 server lying around. And yes it did the same thing: 0.1 0.1 0.1 0.09985 0.09985 0.1 0.09985 0.1 0.1 0.09985 0.1 0.09985 0.09985 0.09985 0.1 0.1 0.1 0.1 0.09985 0.1 There's lots of references to this common problem, e.g.: http://www.regdeveloper.co.uk/2006/08/12/floating_point_approximation/ As to why you are seeing different results in different CF versions... not sure. But if you code to expect the rounding errors, then it won't matter. From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:53 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 What about 7.01 or 7.00? or 6.1 or 6? CF5 is not a fair comparison. Cheers Gareth. Ryan Sabir wrote: I just tried it on anold CF5 server and it did the same thing. It's nothing to do with data typing. The underlying calculation to work out whatX * 0.1 is, will always have some degree of rounding error due to the way those numbers are stored in memory. From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:37 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 It hasn't been a problem previously, why would it be a problem now? CFML is not a strong typed language and there for should evaluate situations like this correctly. Cheers Gareth. Ryan Sabir wrote: They looks like pretty standard floating point rounding errors. You get them in any programming language where you deal with fractions. The trick is to expect that this will happen and plan your application around it. -Original Message- From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 12:05 PM To: CFAussie Mailing List Subject: [cfaussie] Strange calculation behavior on CF 7.02 If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from="1" to="1000" index="i" cfset a = RandRange(1,2) cfset b = a*2 cfset c = "#ListFirst(Trim(a),".")#.00" cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Now you show me in the Coldfusion Documentation where this is outlined as a known issue? Cheers Gareth. Ryan Sabir wrote: Doesn't really matter why... Maybe there's a gremlin that lives in the last 0.00015 of every floating point number. Every now and then he will wake up and mess up your number, and sometime's he'll stay asleep. Write your code expecting he might pop round for a visit, and he won't bother you. If you really want to find out why, then you'll need to do some pretty hard core maths to work out how fractions are represented in binary. I prefer to leave that to the geeks who work at Intel and AMD while I get on with my work. From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:11 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 So why the mixed result? Cheers Gareth. Ryan Sabir wrote: Just remembered I had a 6.1 server lying around. And yes it did the same thing: 0.1 0.1 0.1 0.09985 0.09985 0.1 0.09985 0.1 0.1 0.09985 0.1 0.09985 0.09985 0.09985 0.1 0.1 0.1 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Gareth, You have been politely told that this is not a bug, and it does occur on every know programming language that I have ever used. Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:42 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Now you show me in the Coldfusion Documentation where this is outlined as a known issue? Cheers Gareth. Ryan Sabir wrote: Doesn't really matter why... Maybe there's a gremlin that lives in the last 0.00015 of every floating point number. Every now and then he will wake up and mess up your number, and sometime's he'll stay asleep. Write your code expecting he might pop round for a visit, and he won't bother you. If you really want to find out why, then you'll need to do some pretty hard core maths to work out how fractions are represented in binary. I prefer to leave that to the geeks who work at Intel and AMD while I get on with my work. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
I think your missing the point Andrew... Coldfusion is not strongly typed, so one would assume that a simple calculation between a integer and a decimal would come back correctly. Cheers Gareth Andrew Scott wrote: Gareth, You have been politely told that this is not a bug, and it does occur on every know programming language that I have ever used. Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone:+613 8676 4223 Mobile: 0404 998 273 From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:42 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Now you show me in the Coldfusion Documentation where this is outlined as a known issue? Cheers Gareth. Ryan Sabir wrote: Doesn't really matter why... Maybe there's a gremlin that lives in the last 0.00015 of every floating point number. Every now and then he will wake up and mess up your number, and sometime's he'll stay asleep. Write your code expecting he might pop round for a visit, and he won't bother you. If you really want to find out why, then you'll need to do some pretty hard core maths to work out how fractions are represented in binary. I prefer to leave that to the geeks who work at Intel and AMD while I get on with my work. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Here's a technote from Sun, regarding Java.. the underlying subsystem of ColdFusion: http://java.sun.com/developer/JDCTechTips/2001/tt0807.html I wouldn't expect this to be in the CF documentation. It's not Adobe's problem. From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:42 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Now you show me in the Coldfusion Documentation where this is outlined as a known issue? Cheers Gareth. Ryan Sabir wrote: Doesn't really matter why... Maybe there's a gremlin that lives in the last 0.00015 of every floating point number. Every now and then he will wake up and mess up your number, and sometime's he'll stay asleep. Write your code expecting he might pop round for a visit, and he won't bother you. If you really want to find out why, then you'll need to do some pretty hard core maths to work out how fractions are represented in binary. I prefer to leave that to the geeks who work at Intel and AMD while I get on with my work. From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:11 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 So why the mixed result? Cheers Gareth. Ryan Sabir wrote: Just remembered I had a 6.1 server lying around. And yes it did the same thing: 0.1 0.1 0.1 0.09985 0.09985 0.1 0.09985 0.1 0.1 0.09985 0.1 0.09985 0.09985 0.09985 0.1 0.1 0.1 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Who's missing my point? One shouldn't have to worry about typing in Coldfusion. If in an evaluation a decimal is found amongst integers, it should still calculate correctly. Whether it does this by making the other values decimals, I don't care, but Coldfusion is a plain English language, and it not typed, there for if one reads cfdump var="#1024-1024.1#" as -0.1 I think that is what coldfusion should return. Cheers Gareth. Ryan Sabir wrote: Here's a technote from Sun, regarding Java.. the underlying subsystem of ColdFusion: http://java.sun.com/developer/JDCTechTips/2001/tt0807.html I wouldn't expect this to be in the CF documentation. It's not Adobe's problem. From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:42 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Now you show me in the Coldfusion Documentation where this is outlined as a known issue? Cheers Gareth. Ryan Sabir wrote: Doesn't really matter why... Maybe there's a gremlin that lives in the last 0.00015 of every floating point number. Every now and then he will wake up and mess up your number, and sometime's he'll stay asleep. Write your code expecting he might pop round for a visit, and he won't bother you. If you really want to find out why, then you'll need to do some pretty hard core maths to work out how fractions are represented in binary. I prefer to leave that to the geeks who work at Intel and AMD while I get on with my work. From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:11 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 So why the mixed result? Cheers Gareth. Ryan Sabir wrote: Just remembered I had a 6.1 server lying around. And yes it did the same thing: 0.1 0.1 0.1 0.09985 0.09985 0.1 0.09985 0.1 0.1 0.09985 0.1 0.09985 0.09985 0.09985 0.1 0.1 0.1 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Gareth, I think you are missing the point, whether coldfusion is a typed language or not. The underlying technology of CF has a problem with what your asking. Now just a fresher in how CF works for you, Coldfusion will always try to treat everything as a numerical value first if this throws an exception it is then treated as a string. Now because CF has that, that doesn't mean that I see variable=1024-1024.1 and treat the example as you are asking why. Because of the problem that Ryan has stated to you, and it doesn't matter what language you are in, it will be the same problem. If I write that in JS I should expect the same thing as your asking, but I know that there is a chance of that floating point rearing its ugly head. And that Gareth is a fact of life as a program. Deal with it or move on, Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 2:14 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Who's missing my point? One shouldn't have to worry about typing in Coldfusion. If in an evaluation a decimal is found amongst integers, it should still calculate correctly. Whether it does this by making the other values decimals, I don't care, but Coldfusion is a plain English language, and it not typed, there for if one reads cfdump var=#1024-1024.1# as -0.1 I think that is what coldfusion should return. Cheers Gareth. Ryan Sabir wrote: Here's a technote from Sun, regarding Java.. the underlying subsystem of ColdFusion: http://java.sun.com/developer/JDCTechTips/2001/tt0807.html I wouldn't expect this to be in the CF documentation. It's not Adobe's problem. _ From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:42 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 Now you show me in the Coldfusion Documentation where this is outlined as a known issue? Cheers Gareth. Ryan Sabir wrote: Doesn't really matter why... Maybe there's a gremlin that lives in the last 0.00015 of every floating point number. Every now and then he will wake up and mess up your number, and sometime's he'll stay asleep. Write your code expecting he might pop round for a visit, and he won't bother you. If you really want to find out why, then you'll need to do some pretty hard core maths to work out how fractions are represented in binary. I prefer to leave that to the geeks who work at Intel and AMD while I get on with my work. _ From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Gareth Edwards Sent: Tuesday, 20 February 2007 1:11 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 So why the mixed result? Cheers Gareth. Ryan Sabir wrote: Just remembered I had a 6.1 server lying around. And yes it did the same thing: 0.1 0.1 0.1 0.09985 0.09985 0.1 0.09985 0.1 0.1 0.09985 0.1 0.09985 0.09985 0.09985 0.1 0.1 0.1 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Indicating you know how Coldfusion works really proves nothing, I'm
quite aware of how it all works. I'm just annoyed that Coldfusion
doesn't deal with this situation better than it does.
Once again, _javascript_, although not strictly typed, is a typed
language. If I could type in Coldfusion I would.
Also, Coldfusion should get this one right, but it doesn't cfdump
var="#1024.00-1024.10#" returns -0.0
Cheers
Gareth.
Andrew Scott wrote:
Gareth,
I
think you are missing the point, whether coldfusion is a typed
language or not. The underlying technology of CF has a problem with
what your
asking.
Now
just a fresher in how CF works for you, Coldfusion will
always try to treat everything as a numerical value first if this
throws an exception
it is then treated as a string. Now because CF has that, that doesnt
mean that
I see variable=1024-1024.1 and treat the example as you are asking why.
Because
of the problem that Ryan has stated to you, and it doesnt matter what
language
you are in, it will be the same problem. If I write that in JS I should
expect
the same thing as your asking, but I know that there is a chance of
that
floating point rearing its ugly head.
And
that Gareth is a fact of life as a program. Deal with it or
move on,
Andrew Scott
Senior Coldfusion Developer
Aegeon Pty. Ltd.
www.aegeon.com.au
Phone:+613 8676 4223
Mobile:
0404 998
273
From:
cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com] On
Behalf Of Gareth
Edwards
Sent: Tuesday, 20 February 2007 2:14 PM
To: cfaussie@googlegroups.com
Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02
Who's missing my point? One shouldn't have to
worry about
typing in Coldfusion. If in an evaluation a decimal is found amongst
integers,
it should still calculate correctly. Whether it does this by making the
other
values decimals, I don't care, but Coldfusion is a plain English
language, and
it not typed, there for if one reads cfdump
var="#1024-1024.1#" as -0.1 I think that is what coldfusion
should return.
Cheers
Gareth.
Ryan Sabir wrote:
Here's
a technote
from Sun, regarding Java.. the underlying subsystem of ColdFusion:
http://java.sun.com/developer/JDCTechTips/2001/tt0807.html
I
wouldn't expect
this to be in the CF documentation. It's not Adobe's problem.
From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com]
On
Behalf Of Gareth Edwards
Sent: Tuesday, 20 February 2007 1:42 PM
To: cfaussie@googlegroups.com
Subject: [cfaussie] Re: Strange calculation behavior on CF
7.02
Now you show me in the Coldfusion
Documentation where
this is outlined as a known issue?
Cheers
Gareth.
Ryan Sabir wrote:
Doesn't
really
matter why... Maybe there's a gremlin that lives in the last
0.00015 of
every floating point number. Every now and then he will wake up and
mess up
your number, and sometime's he'll stay asleep. Write your code
expecting he
might pop round for a visit, and he won't bother you.
If
you really want
to find out why, then you'll need to do some pretty hard core maths to
work out
how fractions are represented in binary. I prefer to leave that to the
geeks
who work at Intel and AMD while I get on with my work.
From: cfaussie@googlegroups.com [mailto:cfaussie@googlegroups.com]
On
Behalf Of Gareth Edwards
Sent: Tuesday, 20 February 2007 1:11 PM
To: cfaussie@googlegroups.com
Subject: [cfaussie] Re: Strange calculation behavior on CF
7.02
So why the mixed result?
Cheers
Gareth.
Ryan Sabir wrote:
Just
remembered I
had a 6.1 server lying around. And yes it did the same thing:
0.1
0.1
0.1
0.09985
0.09985
0.1
0.09985
0.1
0.1
0.09985
0.1
0.09985
0.09985
0.09985
0.1
0.1
0.1
--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
It's easier to see the pattern without the random stuff and the extra additions and subtractions, note val() etc have nothing to do with it: cfloop from=1 to=1 index=a cfset c = a + 0.1 cfset d = a - c cfoutput#a# - #c# = #d#br//cfoutput /cfloop 1019 - 1019.1 = -0.1 1020 - 1020.1 = -0.1 1021 - 1021.1 = -0.1 1022 - 1022.1 = -0.1 1023 - 1023.1 = -0.1 1024 - 1024.1 = -0.0 1025 - 1025.1 = -0.0 1026 - 1026.1 = -0.0 1027 - 1027.1 = -0.0 1028 - 1028.1 = -0.0 ... 4090 - 4090.1 = -0.0 4091 - 4091.1 = -0.0 4092 - 4092.1 = -0.0 4093 - 4093.1 = -0.0 4094 - 4094.1 = -0.0 4095 - 4095.1 = -0.0 4096 - 4096.1 = -0.1 4097 - 4097.1 = -0.1 4098 - 4098.1 = -0.1 4099 - 4099.1 = -0.1 4100 - 4100.1 = -0.1 4101 - 4101.1 = -0.1 4102 - 4102.1 = -0.1 4103 - 4103.1 = -0.1 4104 - 4104.1 = -0.1 I get errors for the range 1024 = a 4096. Note 1024 = 2 ^ 10 and 4096 = 2 ^ 12 - significant numbers in the binary world. These sorts of errors are caused because you cannot represent all fractional amounts in a finite number of binary digits - for instance 0.1 is an endlessly repeating 1100110011001100... pattern in binary (just like 1/3 is an endlessly repeating series in decimal). Replace 0.1 in the above code with 0.125 (1/8) or another fraction that can be represented in a finite number of binary digits and you'll see the error disappears, or if you use 0.7 you'll see the error kick in at a = 8192 (2 ^ 13). Without further analysis, it's probably something to do with the way negative numbers (see two's complement) are represented in binary, and the point in the repeating sequence of binary digits where a Java floating point number runs out of precision. As Ryan suggested, these rounding errors happen on any digital computer/language and your code needs to deal with them gracefully. Cheers, Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 e[EMAIL PROTECTED] or Direct: m+61 418 414 341 e[EMAIL PROTECTED] On 20/02/2007, at 12:04 PM, Gareth Edwards wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Sorry to complain about it, it just seems strange, I won't complain anymore. Does it do the same thing in Actionscript? (don't have time to check right now) What do you think is the best way to handle this in coldfusion? Also, I'm curious, how many people on this list are aware of this issue? Cheers Gareth. Robin Hilliard wrote: It's easier to see the pattern without the random stuff and the extra additions and subtractions, note val() etc have nothing to do with it: cfloop from="1" to="1" index="a" cfset c = a + 0.1 cfset d = a - c cfoutput#a# - #c# = #d#br//cfoutput /cfloop 1019 - 1019.1 = -0.1 1020 - 1020.1 = -0.1 1021 - 1021.1 = -0.1 1022 - 1022.1 = -0.1 1023 - 1023.1 = -0.1 1024 - 1024.1 = -0.0 1025 - 1025.1 = -0.0 1026 - 1026.1 = -0.0 1027 - 1027.1 = -0.0 1028 - 1028.1 = -0.0 ... 4090 - 4090.1 = -0.0 4091 - 4091.1 = -0.0 4092 - 4092.1 = -0.0 4093 - 4093.1 = -0.0 4094 - 4094.1 = -0.0 4095 - 4095.1 = -0.0 4096 - 4096.1 = -0.1 4097 - 4097.1 = -0.1 4098 - 4098.1 = -0.1 4099 - 4099.1 = -0.1 4100 - 4100.1 = -0.1 4101 - 4101.1 = -0.1 4102 - 4102.1 = -0.1 4103 - 4103.1 = -0.1 4104 - 4104.1 = -0.1 I get errors for the range 1024 = a 4096. Note 1024 = 2 ^ 10 and 4096 = 2 ^ 12 - significant numbers in the binary world. These sorts of errors are caused because you cannot represent all fractional amounts in a finite number of binary digits - for instance 0.1 is an endlessly repeating 1100110011001100... pattern in binary (just like 1/3 is an endlessly repeating series in decimal). Replace 0.1 in the above code with 0.125 (1/8) or another fraction that can be represented in a finite number of binary digits and you'll see the error disappears, or if you use 0.7 you'll see the error kick in at a = 8192 (2 ^ 13). Without further analysis, it's probably something to do with the way negative numbers (see "two's complement") are represented in binary, and the point in the repeating sequence of binary digits where a Java floating point number runs out of precision. As Ryan suggested, these rounding errors happen on any digital computer/language and your code needs to deal with them gracefully. Cheers, Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 e[EMAIL PROTECTED] or Direct: m+61 418 414 341 e[EMAIL PROTECTED] On 20/02/2007, at 12:04 PM, Gareth Edwards wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from="1" to="1000" index="i" cfset a = RandRange(1,2) cfset b = a*2 cfset c = "#ListFirst(Trim(a),".")#.00" cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
to part answer that, what were you doing to bring this matter to your attention? On 2/20/07, Gareth Edwards [EMAIL PROTECTED] wrote: Sorry to complain about it, it just seems strange, I won't complain anymore. Does it do the same thing in Actionscript? (don't have time to check right now) What do you think is the best way to handle this in coldfusion? Also, I'm curious, how many people on this list are aware of this issue? Cheers Gareth. Robin Hilliard wrote: It's easier to see the pattern without the random stuff and the extra additions and subtractions, note val() etc have nothing to do with it: cfloop from=1 to=1 index=a cfset c = a + 0.1 cfset d = a - c cfoutput#a# - #c# = #d#br//cfoutput /cfloop 1019 - 1019.1 = -0.1 1020 - 1020.1 = -0.1 1021 - 1021.1 = -0.1 1022 - 1022.1 = -0.1 1023 - 1023.1 = -0.1 1024 - 1024.1 = -0.0 1025 - 1025.1 = -0.0 1026 - 1026.1 = -0.0 1027 - 1027.1 = -0.0 1028 - 1028.1 = -0.0 ... 4090 - 4090.1 = -0.0 4091 - 4091.1 = -0.0 4092 - 4092.1 = -0.0 4093 - 4093.1 = -0.0 4094 - 4094.1 = -0.0 4095 - 4095.1 = -0.0 4096 - 4096.1 = -0.1 4097 - 4097.1 = -0.1 4098 - 4098.1 = -0.1 4099 - 4099.1 = -0.1 4100 - 4100.1 = -0.1 4101 - 4101.1 = -0.1 4102 - 4102.1 = -0.1 4103 - 4103.1 = -0.1 4104 - 4104.1 = -0.1 I get errors for the range 1024 = a 4096. Note 1024 = 2 ^ 10 and 4096 = 2 ^ 12 - significant numbers in the binary world. These sorts of errors are caused because you cannot represent all fractional amounts in a finite number of binary digits - for instance 0.1 is an endlessly repeating 1100110011001100... pattern in binary (just like 1/3 is an endlessly repeating series in decimal). Replace 0.1 in the above code with 0.125 (1/8) or another fraction that can be represented in a finite number of binary digits and you'll see the error disappears, or if you use 0.7 you'll see the error kick in at a = 8192 (2 ^ 13). Without further analysis, it's probably something to do with the way negative numbers (see two's complement) are represented in binary, and the point in the repeating sequence of binary digits where a Java floating point number runs out of precision. As Ryan suggested, these rounding errors happen on any digital computer/language and your code needs to deal with them gracefully. Cheers, Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w +61 7 5451 0362 m +61 419 677 151 f +61 3 9923 6261 e [EMAIL PROTECTED] or Direct: m +61 418 414 341 e [EMAIL PROTECTED] On 20/02/2007, at 12:04 PM, Gareth Edwards wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Our teacher gave us the low down on this issue in the first week of my C unit. You probably dont hear about it too much in CF land as its so losely typed. cheers Drew Peacock -Original Message- From: Gareth Edwards [EMAIL PROTECTED] To: cfaussie@googlegroups.com Date: Tue, 20 Feb 2007 14:27:34 +1000 Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 !DOCTYPE html PUBLIC -//W3C//DTD HTML 4.01 Transitional//EN html head meta content=text/html;charset=ISO-8859-1 http-equiv=Content-Type /head body bgcolor=#ff text=#00 Sorry to complain about it, it just seems strange, I won't complain anymore. Does it do the same thing in Actionscript? (don't have time to check right now)br br What do you think is the best way to handle this in coldfusion?br br Also, I'm curious, how many people on this list are aware of this issue?br br Cheersbr Gareth.br br Robin Hilliard wrote: blockquote cite=mid:[EMAIL PROTECTED] type=cite pre wrap=It's easier to see the pattern without the random stuff and the extra additions and subtractions, note val() etc have nothing to do with it: lt;cfloop from=1 to=1 index=agt; lt;cfset c = a + 0.1gt; lt;cfset d = a - cgt; lt;cfoutputgt;#a# - #c# = #d#lt;br/gt;lt;/cfoutputgt; lt;/cfloopgt; 1019 - 1019.1 = -0.1 1020 - 1020.1 = -0.1 1021 - 1021.1 = -0.1 1022 - 1022.1 = -0.1 1023 - 1023.1 = -0.1 1024 - 1024.1 = -0.0 1025 - 1025.1 = -0.0 1026 - 1026.1 = -0.0 1027 - 1027.1 = -0.0 1028 - 1028.1 = -0.0 ... 4090 - 4090.1 = -0.0 4091 - 4091.1 = -0.0 4092 - 4092.1 = -0.0 4093 - 4093.1 = -0.0 4094 - 4094.1 = -0.0 4095 - 4095.1 = -0.0 4096 - 4096.1 = -0.1 4097 - 4097.1 = -0.1 4098 - 4098.1 = -0.1 4099 - 4099.1 = -0.1 4100 - 4100.1 = -0.1 4101 - 4101.1 = -0.1 4102 - 4102.1 = -0.1 4103 - 4103.1 = -0.1 4104 - 4104.1 = -0.1 I get errors for the range 1024 lt;= a lt; 4096. Note 1024 = 2 ^ 10 and 4096 = 2 ^ 12 - significant numbers in the binary world. These sorts of errors are caused because you cannot represent all fractional amounts in a finite number of binary digits - for instance 0.1 is an endlessly repeating 1100110011001100... pattern in binary (just like 1/3 is an endlessly repeating series in decimal). Replace 0.1 in the above code with 0.125 (1/8) or another fraction that can be represented in a finite number of binary digits and you'll see the error disappears, or if you use 0.7 you'll see the error kick in at a gt;= 8192 (2 ^ 13). Without further analysis, it's probably something to do with the way negative numbers (see two's complement) are represented in binary, and the point in the repeating sequence of binary digits where a Java floating point number runs out of precision. As Ryan suggested, these rounding errors happen on any digital computer/language and your code needs to deal with them gracefully. Cheers, Robin __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training a class=moz-txt-link-freetext href=http://www.rocketboots.com.au;http://www.rocketboots.com.au/a For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 ea class=moz-txt-link-abbreviated href=mailto:[EMAIL PROTECTED][EMAIL PROTECTED]/a or Direct: m+61 418 414 341 ea class=moz-txt-link-abbreviated href=mailto:[EMAIL PROTECTED][EMAIL PROTECTED]/a On 20/02/2007, at 12:04 PM, Gareth Edwards wrote: /pre blockquote type=cite pre wrap=If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? lt;cfset a = 0gt; lt;cfset b = 0gt; lt;cfset c = 0gt; lt;cfloop from=1 to=1000 index=igt; lt;cfset a = RandRange(1,2)gt; lt;cfset b = a*2gt; lt;cfset c = #ListFirst(Trim(a),.)#.00gt; lt;cfset c = c + 0.1gt; lt;cfset d = a - val(b) + val(c)gt; lt;cfoutputgt;#d#lt;br /gt;lt;/cfoutputgt; lt;/cfloopgt; Cheers Gareth. /pre /blockquote pre wrap=! /pre /blockquote br br /body /html br --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Restrict the decimal paces and force a round off! Andrew Scott Senior Coldfusion Developer Aegeon Pty. Ltd. www.aegeon.com.au Phone: +613 8676 4223 Mobile: 0404 998 273 --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
Do you get the same issue with punch cards? Maybe that's an option:P What is it your trying to do in the first place? Or were you just having an I wonder what would happen if... moment? Steve _ From: cfaussie@googlegroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Robin Hilliard Sent: Tuesday, 20 February 2007 3:54 PM To: cfaussie@googlegroups.com Subject: [cfaussie] Re: Strange calculation behavior on CF 7.02 On 20/02/2007, at 3:27 PM, Gareth Edwards wrote: Sorry to complain about it, Don't worry, you were somewhat provoked over the course of the thread (I would recommend the more frequent posters on cfaussie buy a copy of Parent Effectiveness Training by Dr. Thomas R. Gordon ISBN 0609806939 to find out how to peacefully turn a confrontation into a win/win situation for everyone), the original question was fair enough :) it just seems strange, I won't complain anymore. Does it do the same thing in Actionscript? (don't have time to check right now) It should. What do you think is the best way to handle this in coldfusion? If you only wanted to nearest 0.1 you could say: nice = round(possiblyyuck * 10) / 10 Also, I'm curious, how many people on this list are aware of this issue? Developers doing floating point calculations in any programming language comes across it sooner or later - on a digital computer*. Cheers, Robin * The only mechanical computer I've seen (not working) that wouldn't run into this is the _analog_ computer that used to be in the basement of the computer science faculty at Sydney Uni, preserved by the late Prof. Alan Bromley. This was the sort of thing they used for the Apollo program - it looked like a big grey tote board - you'd actually wire up a differential equation with patch leads, set the inputs using dials, the current would flow and you'd read the results from an oscilloscope. __ Robin Hilliard Director - RocketBoots Pty Ltd Consulting . Recruitment . Software Licensing . Training http://www.rocketboots.com.au For schedule/availability call Pamela Higgins: w+61 7 5451 0362 m+61 419 677 151 f+61 3 9923 6261 e[EMAIL PROTECTED] or Direct: m+61 418 414 341 e[EMAIL PROTECTED] --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
[cfaussie] Re: Strange calculation behavior on CF 7.02
If you use the java class and methods that handle these types of numbers I don't see the problem?? cfloop from=1 to=1000 index=i cfset diff = CreateObject(Java, java.math.BigDecimal).init(0.1) cfset a = CreateObject(Java, java.math.BigDecimal).init(RandRange(100,1)) cfset b = CreateObject(Java, java.math.BigDecimal).init(a*2) cfset c = CreateObject(Java, java.math.BigDecimal).init(val(a)) cfset c = c.add(diff) cfset d = a.subtract(b).add(c) cfoutput#a#-#b#+#c# = #d#br //cfoutput /cfloop It seems CF is using some sort of toString() value during the calculation at some stage?? hth Rod On Feb 20, 12:04 pm, Gareth Edwards [EMAIL PROTECTED] wrote: If you are running coldfusion 7.02, or maybe 7.01 or 7.0? (don't know) Run this script below, and tell me if you get the same results for each line. The way I see it, d should equal 0.1 on every row. But this isn't the case. Is this a bug introduced by Coldfusion 7.02? cfset a = 0 cfset b = 0 cfset c = 0 cfloop from=1 to=1000 index=i cfset a = RandRange(1,2) cfset b = a*2 cfset c = #ListFirst(Trim(a),.)#.00 cfset c = c + 0.1 cfset d = a - val(b) + val(c) cfoutput#d#br //cfoutput /cfloop Cheers Gareth. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups cfaussie group. To post to this group, send email to cfaussie@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfaussie?hl=en -~--~~~~--~~--~--~---
