Re: [PD] expr modulo negative
Hallo, Hans Roels hat gesagt: // Hans Roels wrote: Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? Not really: Pd also has a builting [% ] object, which behaves like the % in expr. Ciao -- Frank Barknecht _ __footils.org__ ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] expr modulo negative
Hans Roels wrote: Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? you also get a different result if you use [mod] or [%]. it's a feature. fgmasdr IOhannes Hans r ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] expr modulo negative
you can use pd [mod] object or [%] object. it's not the same for negative umber. expr % is the same than pd %. so i don't see any bug. Cyrille Hans Roels a écrit : Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? Hans r ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] expr modulo negative
[%] and [mod] treat the sign differently. [mod] is monotonic but [%] is symmetrical about zero. On Tue, 14 Oct 2008 13:45:50 +0100 Hans Roels [EMAIL PROTECTED] wrote: Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? Hans r ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Use the source ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] expr modulo negative
maybe someone could explain _what_ the difference is? that would be enlightening vor everybody. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] expr modulo negative
ok, so there is no expr function identical to the 'mod' object? Hans r At 13:09 14/10/2008, Frank Barknecht wrote: Hallo, Hans Roels hat gesagt: // Hans Roels wrote: Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? Not really: Pd also has a builting [% ] object, which behaves like the % in expr. Ciao -- Frank Barknecht _ __footils.org__ ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
[PD] expr modulo negative
Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? Hans r ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] expr modulo negative
I think that since Miller is a self-described math geek, the difference is
that [mod] behaves like the mathematical (mod n). [%] is the modulo operator
used by computer science.
If my memory serves me, in number theory and abstract algebra, the m (mod n)
notation is used to define a subset of the integers (called a congruence
class) which contains n-1 elements.
For example, 5 (mod 3) == 2. Likewise, -5 (mod 3) == -2 (mod 3) == 1 (mod 3)
== 1. Note that my use of == here represents congruence and not necessarily
equality.
See http://en.wikipedia.org/wiki/Modular_arithmetic for a much more informed
discussion of this topic.
~Kyle
On Tue, Oct 14, 2008 at 7:40 AM, Max [EMAIL PROTECTED] wrote:
maybe someone could explain _what_ the difference is?
that would be enlightening vor everybody.
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Re: [PD] expr modulo negative
thank you andy. i guess it is a bug anyway, not in the objects, but in the documentation. both open the same helppatch with no mention about the difference. max Am 14.10.2008 um 14:32 schrieb Andy Farnell: [%] and [mod] treat the sign differently. [mod] is monotonic but [%] is symmetrical about zero. On Tue, 14 Oct 2008 13:45:50 +0100 Hans Roels [EMAIL PROTECTED] wrote: Hello, If you want to calculate the modulo of a negative number, you get a different result if you use the 'mod' object or 'expr' with %. -1 4 || mod | 3 -1 4 | | expr $f1 % $f2 | -1 I guess this is a bug in expr ? Hans r ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/ listinfo/pd-list -- Use the source ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/ listinfo/pd-list PGP.sig Description: Signierter Teil der Nachricht ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
