在 2020/8/10 下午11:31, Takashi Inoue 写道: > Hi All, > > Finally, I found the minimal condition of my problem. > Attached very simple code reproduce the problem. > You will get different result(fort.99) at time to time. > > Essential point is combination of power operation(**) > and "omp do schedule(dynamic,chunk-size)". > If we have operation ** in a do loop parallelized > with schedule(dynamic), result becomes unstable. > I don't know fundamental origin of this problem. > But, I believe this is unexpected abnormal behavior. > > As I wrote, my mingw-w64 is a x86_64 package of msys2. > I have not tested other versions of mingw-w64 yet. > So, I would be grateful if you could test on your system. > > Any comments and suggestions will be appreciated. >
You forgot to attach the program file. Would you please provide a C testcase instead? I know no FORTRAN, and I don't think many of us do. Or rather, would you please provide two operands to the power operator, which yield different results on mingw-w64 and FreeBSD etc.? Note in order to prevent round-off errors there should be at least 17 significant figures for IEEE 754 double-precision numbers. -- Best regards, LH_Mouse
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