On 03/06/2013, Irek Szczesniak wrote: > 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).
Discard any so-called "high-precision scientific software" which does not verify experimentally at run time the actual precision used for operations and operands. Such software is junk. Who would run an experiment without controls? Adequate software will diagnose the situation, emit a message which gives both the expected and the actually-encountered precision, and then exit without attempting computation in a degraded environment. Better software will perform the diagnosis, emit a message, and offer options such as: quit, proceed "full speed" at lower precision, or proceed but use the available precision to "emulate" higher precision. Now about ranting: please identify "the NIH lists". [valgrind-users] and [valgrind-developers] are world-wide forums. A reasonable guess is the National Institutes of Health of the United States of America, http://www.nih.gov, but finding "the NIH lists" requires further digging. [Lacking a citation, one can also read NIH as "Not Invented Here."] While I have encountered cases where more than 53 bits of precision truly are required, many many projects use wider precision as a crutch in order to avoid actual numerical analysis. Some of those projects still get junk results without knowing. Do the numerical analysis! I too would like memcheck to support 80-bit and 128-bit floating point. However, there are competing products which do so already. Purify from Rational Software is one, Insure++ from Parasoft may be another. Yes, they cost money; a license can cost less than the burdened cost of one laboratory assistant for one month. So, buy a license; and if necessary then share with co-workers or neighboring projects. -- ------------------------------------------------------------------------------ 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
