----- Original Message ----- > Unfortunately the assessment that there are only "small changes" or > "unimportant differences" is plain wrong. In complex calculations > (i.e. no one line "hello sin() world" demo apps) which rely on the > wider datatypes the lack of precision will cause major malfunctions > and render the applications defunct. There are enough examples for > this kind of problems (and enough complains about valgrind in the NIH > lists).
Hi There are two issues here. Emulation of long double and exact emulation of x87 double. Adding the first of those to Valgrind seems reasonable to me, but I would be most put out if Valgrind were made much slower by adding exact x87 emulation. Other than the 2 cases that you cite, can you name any other major uses of long double? As a somewhat non-scientific measure, I used google to search for 'double C++ -"long double"' and it had about 13 million hits [that's a search for double and C++ exclusing long double]. I then searched for '"long double" C++' and had about 300 thousand hits. I for one do not accept your assertion that most scientific and engineering software is written using long double precision. And to be a bit more precise 64bit double has 53bits of precision, or about 1.1e-16 ULP 80bit floating point has 64bits, or about 5.4e-20 ULP I've run many thousands of electronic circuit simulations (hardly a "demo app"; there is a small amount of code using long double) under Valgrind and my observation is that over 90% have no detectable difference, around 10% have insignificant differences and a handful have major differences. A+ Paul ------------------------------------------------------------------------------ Symantec Endpoint Protection 12 positioned as A LEADER in The Forrester Wave(TM): Endpoint Security, Q1 2013 and "remains a good choice" in the endpoint security space. For insight on selecting the right partner to tackle endpoint security challenges, access the full report. http://p.sf.net/sfu/symantec-dev2dev _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
