[Octave-bug-tracker] [bug #45507] acos returns different results on big input values on gcc 4.8

[Markus Mützel]

Follow-up Comment #56, bug #45507 (project octave):

These tests now appear as regressions on Windows 10 64bit:

D:\Repositories\Octave\test\octave-2017-09-17-18-08_clean_gcc7_2_qt5\octave-2017-09-17-18-08\share\octave\4.3.0+\etc\tests\libinterp\corefcn\mappers.cc-tst
***** test <*45507>
 x = [1, -1, i, -i] .* 1e150;
 v = [0, pi, pi/2, pi/2];
 assert (real (acos (x)), v);
!!!!! regression: http://octave.org/testfailure/?45507
ASSERT errors for:  assert (real (acos (x)),v)

  Location  |  Observed  |  Expected  |  Reason
    (1)         1.5708         0         Abs err 1.5708 exceeds tol 0
    (2)         1.5708       3.1416      Abs err 1.5708 exceeds tol 0
shared variables   scalar structure containing the fields:

    rt2 =  1.4142
    rt3 =  1.7321
[snip]
***** test <*45507>
 x = [1, -1, i, -i] .* 1e150;
 v = [0, pi, pi/2, -pi/2];
 assert (imag (acosh (x)), v);
!!!!! regression: http://octave.org/testfailure/?45507
ASSERT errors for:  assert (imag (acosh (x)),v)

  Location  |  Observed  |  Expected  |  Reason
    (4)           -0        -1.5708      Abs err 1.5708 exceeds tol 0
shared variables   scalar structure containing the fields:

    rt2 =  1.4142
    rt3 =  1.7321
***** test <*45507>
 x = [1, -1, i, -i] .* 1e150;
 v = [pi/2, -pi/2, 0, -0];
 assert (real (asin (x)), v);
!!!!! regression: http://octave.org/testfailure/?45507
ASSERT errors for:  assert (real (asin (x)),v)

  Location  |  Observed  |  Expected  |  Reason
    (1)           0          1.5708      Abs err 1.5708 exceeds tol 0
    (2)           0         -1.5708      Abs err 1.5708 exceeds tol 0
shared variables   scalar structure containing the fields:

    rt2 =  1.4142
    rt3 =  1.7321
***** test <*45507>
 x = [1, -1, i, -i] .* 1e150;
 v = [0, 0, pi/2, -pi/2];
 assert (imag (asinh (x)), v);
!!!!! regression: http://octave.org/testfailure/?45507
ASSERT errors for:  assert (imag (asinh (x)),v)

  Location  |  Observed  |  Expected  |  Reason
    (4)           0         -1.5708      Abs err 1.5708 exceeds tol 0
shared variables   scalar structure containing the fields:

    rt2 =  1.4142
    rt3 =  1.7321


This might be related to the other failing tests in bug #49091. However, those
are accuracy related and these tests are off by pi/2. So it might be a
different bug in mingw-w64.

I looked through a few older test runs on Windows (during the last 6 months)
and these tests seem to have always failed. Should these be marked as xtest
again?

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?45507>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/