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Re: Problems with GAMMA functions?


Jerry DeLisle wrote:
Thomas Koenig wrote:
On Mon, 2007-10-08 at 13:28 +0200, Angelo Graziosi wrote:

I have tried the test gfc_gamma_test_c302m.F
(http://gcc.gnu.org/ml/fortran/2007-10/msg00096.html) on GNU/Linux kubuntu
Feisty 7.04 with GFortran 20071008-129121 and it still fails:

We are now using the gamma functions provided by the respective C libraries. Looking at the gcc-testresults failures, and at your report, it seems as if the quality of existing gamma functions is rather low.

At the least, we should

- relax the tolerances in gamma_5.f90 to something that doesn't fail
  on as many systems

- note in the documentation that the GAMMA functions are sometimes
  inaccurate, and people may be better off using an external
  gamma function.

Maybe we should also provide our own, higher-quality gamma function,
but I don't see that in the 4.3 timeframe (not if I have to do
it, at least :-)

Thomas


The test case is failing for me on x86-64-Gnu-linux. I suspect it is tolerance as you suggest.

Jerry

I should add that it passes with -m32 and fails with -m64. I will have to investigate further later.

Jerry


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