Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Tue, Nov 30, 2010 at 12:29 AM, Shane Harrelson wrote: > > I've written two articles about this topic that summarize the problem and how it may be fixed: - http://www.exploringbinary.com/fifteen-digits-dont-round-trip-through-sqlite-reals/ This covers the original

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Tue, Nov 30, 2010 at 12:29 AM, Shane Harrelson wrote: > It turns out the same problem exists on Linux (I used sqlite3-3.7.3.bin); for example: sqlite> create table t1(d float); sqlite> insert into t1 values(9.87e+31); sqlite> select * from t1; 9.870001e+31 So it

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Mon, Nov 29, 2010 at 3:04 PM, Rick Regan <exploringbin...@gmail.com>wrote: > So the question remains -- why does the Windows build get it wrong? > I think I figured it out. It is due to the use of extended precision. In sqlite3.c, if you change "#define LONGDOUBLE

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Sun, Nov 28, 2010 at 8:55 AM, Black, Michael (IS) wrote: > > I find it interesting though that the math is different between the two > compilers...I wonder which is actually "correct" ?? > > > I ran a GMP version of the section of code we've highlighted, converting

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Mon, Nov 29, 2010 at 10:08 AM, Doug Currie wrote: > > The Grisu2 strings do "round trip" correctly, which I think is where this > thread started. > > Grisu addresses the "floating-point to decimal to floating-point" round-trip. The bug I found (it will become a bug

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Sun, Nov 28, 2010 at 8:09 PM, Doug Currie wrote: > The paper compares the performance of sprintf from glibc 2.11 and Grisu. I > don't know if glibc sprintf is based on Gay's code; at one point I thought > it was, but I cannot find an authoritative reference. > > In any

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Sun, Nov 28, 2010 at 5:52 PM, Doug Currie wrote: > > There is a new publication on this subject that may be of interest to those > looking at providing solutions: > > http://portal.acm.org/citation.cfm?id=1806623 > > It (Grisu2) works without bignums if you are willing

Re: [sqlite] Some floats of 15 digits or less do not round-trip

On Sun, Nov 28, 2010 at 4:01 PM, Doug Currie <doug.cur...@gmail.com> wrote: > On Nov 28, 2010, at 11:18 AM, Rick Regan wrote: > > > Michael, > > Thanks for the very thorough analysis. > > This is a difficult problem; fortunately it was solved 20 years ago... > &g

Re: [sqlite] Some floats of 15 digits or less do not round-trip

BTW, I get the CORRECT result when running the precompiled command line on Linux: SQLite version 3.7.3 Enter ".help" for instructions Enter SQL statements terminated with a ";" sqlite> create table t1(d float); sqlite> insert into t1 values(8.948471e15); sqlite> select * from t1; 8.948471e+15

Re: [sqlite] Some floats of 15 digits or less do not round-trip

Michael, Thanks for the very thorough analysis. Yes, sorry, I forgot to state I was running on Windows. The results I got came from running the command window (the precompiled Windows binary sqlite-3_7_3.zip). I also got the same results from compiling the amalgamation

[sqlite] Some floats of 15 digits or less do not round-trip

onversion was not. (This is different than the issue of bug http://www.sqlite.org/src/tktview?name=1248e6cda8 .) Rick Regan -- Check out my blog: http://www.exploringbinary.com ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman