Mantis - ALGLIB
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ID: Category: Severity: Reproducibility: Date Submitted: Last Update:
689 General minor always 2017-03-14 12:49 2017-10-24 13:19
Reporter: smani Platform:  
Assigned To: SergeyB OS:  
Priority: normal OS Version:  
Status: assigned Product Version: 3.10.0  
Product Build: Resolution: open  
Projection: none      
ETA: none Fixed in Version:  
Programming language: C++
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
Steps To Reproduce:
Additional Information:
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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++
2017-10-24 13:19 SergeyB Status new => assigned
2017-10-24 13:19 SergeyB Assigned To => SergeyB

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