bugGNU Scientific Library - Bugs: bug #24162, solve_cyc_tridiag_nonsym does not...


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bug #24162: solve_cyc_tridiag_nonsym does not respect solution vector's stride

Submitter:  Paul Accisano <shiningmasamune>
Submitted:  Fri 29 Aug 2008 05:30:10 PM UTC
Category:  Runtime error Severity:  4 - Important
Operating System:  Status:  Fixed
Assigned to:  bjg Open/Closed:  Closed
Release:  1.11

Sat 30 Aug 2008 01:26:10 PM UTC, comment #1: 

Thanks for the bug report, I've committed your fix to the repository and extended the tests to check non-unit strides.


-Deleted Account- <bjg>
Fri 29 Aug 2008 05:30:10 PM UTC, original submission:  

The function solve_cyc_tridiag_nonsym in linalg_tridiag.c does not respect the stride for the x (solution) vector.  Line 403 reads:

x[N-1] = zb[N-1]/alpha[N-1];

when it should be

x[x_stride * (N-1)] = zb[N-1]/alpha[N-1];

In addition, Line 423 reads:

x[i] -= vx/(1 + vw)*w[i];

when it should be

x[x_stride * i] -= vx/(1 + vw)*w[i];

Those are the only two instances I could find.  After fixing them, the function appears to operate correctly.

Paul Accisano <shiningmasamune>


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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2008-08-30 bjg StatusNone Fixed
        Assigned toNone bjg
        Open/ClosedOpen Closed
    2008-08-30 bjg Severity3 - Normal 4 - Important

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