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ID Category Severity Reproducibility Date Submitted Last Update
0000689 [ALGLIB] General minor always 2017-03-14 12:49 2017-03-14 12:49
Reporter smani View Status public  
Assigned To
Priority normal Resolution open  
Status new   Product Version 3.10.0
Summary 0000689: GCC7: Test failure on i686
Description The ReportCorrectnessTest of the linlsqr test fails on i686 when building with GCC7 (7.0.1 20170309) on Fedora rawhide. The failure occurs in the below section of test_c.cpp (some debug prints were added). The output of this snippet is:

ReportCorrectnessTest::Fail
1 0
TNorm=8107.5250330521303113;RNorm=8107.5250330521294018;S.R2=8107.525033052130;

-----------
/*
 * check, that RNorm is't more than S.R2
 * and difference between S.R2 and TNorm
 * is't more than 'eps'(here S.R2=||rk||,
 * calculated by the algorithm for LSQR, and
 * TNorm=||A*S.x-b||, calculated by test function).
 */
if( ae_fp_greater(s.r2,rnorm)||ae_fp_greater(ae_fabs(s.r2-tnorm, _state),eps) )
{
    if( !silent )
    {
        printf("ReportCorrectnessTest::Fail\n");
        printf("%d %d\n", ae_fp_greater(s.r2,rnorm), ae_fp_greater(ae_fabs(s.r2-tnorm, _state),eps));
        printf("TNorm=%0.16f;RNorm=%0.16f;S.R2=%0.12f;\n",
            (double)(tnorm),
            (double)(rnorm),
            (double)(s.r2));
    }
    result = ae_true;
    ae_frame_leave(_state);
    return result;
}
-----------

By the way, the comment is also a bit confusing. If "is't" actually means "isn't", then the comment states that the test should verify:
rNorm < s.r2 <=> s.r2 > rNorm
|s.r2 - tNorm| < eps

but as far as I see the code fails if:
a) ae_fp_greater(s.r2,rnorm) <=> s.r2 > rNorm
b) ae_fp_greater(ae_fabs(s.r2-tnorm, _state),eps) <=> |s.r2 - tnorm| > eps

So a) matches the comment, but b) does not (and if "is't" means "is", then the opposite is true).


The build is using the following flags:
-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m32 -march=i686 -fasynchronous-unwind-tables -fPIC

Build log is here:
https://koji.fedoraproject.org/koji/getfile?taskID=18371905&name=build.log

Other arches build correctly:
https://koji.fedoraproject.org/koji/taskinfo?taskID=18371900
Additional Information
Programming language C++
Attached Files

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- Issue History
Date Modified Username Field Change
2017-03-14 12:49 smani New Issue
2017-03-14 12:49 smani Programming language => C++


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