[Octave-bug-tracker] [bug #53319] tests: 'test tfqmr.m' fails about 5% of the time

[Mike Miller]

URL:
  <http://savannah.gnu.org/bugs/?53319>

                 Summary: tests: 'test tfqmr.m' fails about 5% of the time
                 Project: GNU Octave
            Submitted by: mtmiller
            Submitted on: Sat 10 Mar 2018 05:01:51 PM PST
                Category: Test Suite
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Inaccurate Result
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: GNU/Linux

    _______________________________________________________

Details:

Test #4 in the newly added function file tfqmr.m fails on its random input
about 5% of the time (about 4-6 times out of 100).

Example:


***** test
 n = 10;
 tol = 1e-8;
 a = (2 * sprand (n, n, .1) - 1) + 1i * (2 * sprand (n, n, .1) - 1);
 A = a + 2 * eye (n);
 b = sum (A, 2);
 [x, flag, relres, iter, resvec] = tfqmr (A, b, tol, [], diag (diag (A)));
 assert (x, ones (size (b)), 1e-7);
!!!!! test failed
ASSERT errors for:  assert (x,ones (size (b)),1e-7)

  Location  |  Observed  |  Expected  |  Reason
    (1)      1-2.1148e-08i      1         Abs err 1.154e-07 exceeds tol 1e-07
by 2e-08
    (10)     1+5.4148e-08i      1         Abs err 1.101e-07 exceeds tol 1e-07
by 1e-08



The largest absolute error I have seen so far is 1.6043e-07 out of a few
thousand trials.

Cc: cdf, cristianodorigo




    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?53319>

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