[GHC] #7968: fft2 benchmark sometimes fails (nofib)

[GHC]

#7968: fft2 benchmark sometimes fails (nofib)
----------------------------------------+-----------------------------------
Reporter:  jstolarek                    |          Owner:                       
    Type:  bug                          |         Status:  new                  
Priority:  normal                       |      Component:  NoFib benchmark suite
 Version:  7.7                          |       Keywords:                       
      Os:  Linux                        |   Architecture:  x86_64 (amd64)       
 Failure:  Incorrect result at runtime  |      Blockedby:                       
Blocking:                               |        Related:                       
----------------------------------------+-----------------------------------
 I noticed that sometimes `fft2` program in nofib benchmark suite returns
 values that are slightly different from expected (see error message at the
 end of this report). The most worrying for me is that it sometimes works
 properly and sometimes fails, as if the correctness of result depended on
 some random factor.

 {{{
 ././fft2 512 < /dev/null
 expected stdout not matched by reality
 --- fft2.stdout7        2013-05-15 08:01:24.014049002 +0200
 +++ /tmp/runtest10927.1 2013-06-04 18:06:08.401977002 +0200
 @@ -1,3 +1,3 @@
 -result1 = 2.59635799135966e-12
 -result2 = 2.59635799135966e-12
 -result3 = 4.8279900966008427e-8
 +result1 = 2.6712796173433053e-12
 +result2 = 2.6712796173433053e-12
 +result3 = 4.827444399779779e-8

 real    0m0.055s
 user    0m0.049s
 sys     0m0.005s
 ././fft2 512 < /dev/null
 expected stdout not matched by reality
 --- fft2.stdout7        2013-05-15 08:01:24.014049002 +0200
 +++ /tmp/runtest10963.1 2013-06-04 18:06:08.507977002 +0200
 @@ -1,3 +1,3 @@
 -result1 = 2.59635799135966e-12
 -result2 = 2.59635799135966e-12
 -result3 = 4.8279900966008427e-8
 +result1 = 2.6712796173433053e-12
 +result2 = 2.6712796173433053e-12
 +result3 = 4.827444399779779e-8

 real    0m0.054s
 user    0m0.047s
 sys     0m0.005s
 ././fft2 512 < /dev/null
 expected stdout not matched by reality
 --- fft2.stdout7        2013-05-15 08:01:24.014049002 +0200
 +++ /tmp/runtest10999.1 2013-06-04 18:06:08.602977002 +0200
 @@ -1,3 +1,3 @@
 -result1 = 2.59635799135966e-12
 -result2 = 2.59635799135966e-12
 -result3 = 4.8279900966008427e-8
 +result1 = 2.6712796173433053e-12
 +result2 = 2.6712796173433053e-12
 +result3 = 4.827444399779779e-8

 real    0m0.052s
 user    0m0.044s
 sys     0m0.007s
 ././fft2 512 < /dev/null
 expected stdout not matched by reality
 --- fft2.stdout7        2013-05-15 08:01:24.014049002 +0200
 +++ /tmp/runtest11035.1 2013-06-04 18:06:08.712977002 +0200
 @@ -1,3 +1,3 @@
 -result1 = 2.59635799135966e-12
 -result2 = 2.59635799135966e-12
 -result3 = 4.8279900966008427e-8
 +result1 = 2.6712796173433053e-12
 +result2 = 2.6712796173433053e-12
 +result3 = 4.827444399779779e-8

 real    0m0.052s
 user    0m0.046s
 sys     0m0.006s
 ././fft2 512 < /dev/null
 expected stdout not matched by reality
 --- fft2.stdout7        2013-05-15 08:01:24.014049002 +0200
 +++ /tmp/runtest11071.1 2013-06-04 18:06:08.816977002 +0200
 @@ -1,3 +1,3 @@
 -result1 = 2.59635799135966e-12
 -result2 = 2.59635799135966e-12
 -result3 = 4.8279900966008427e-8
 +result1 = 2.6712796173433053e-12
 +result2 = 2.6712796173433053e-12
 +result3 = 4.827444399779779e-8
 make[2]: *** [runtests] Błąd 1
 Failed making all in fft2: 1
 make[1]: *** [all] Błąd 1
 Failed making all in spectral: 1
 make: *** [all] Błąd 1
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7968>
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