0000293: SVD Algorithhm crashes on array bounds

Viewing Issue Simple Details [ Jump to Notes ]

[ View Advanced ] [ Issue History ] [ Print ]

Category

Severity

Reproducibility

Date Submitted

Last Update

0000293

[ALGLIB] Linear algebra

crash

always

2010-02-07 22:26

2010-02-08 10:38

Reporter

wvd_vegt

View Status

public

Assigned To

SergeyB

Priority

normal

Resolution

no change required

Status

resolved

Product Version

2.3.0

Summary

0000293: SVD Algorithhm crashes on array bounds

Description

Hi,

When i try to run an SVD the routine crashes on an array index out of bounds in

Test method LsaTest.LsaTests.TestDecompose threw exception: System.IndexOutOfRangeException: De index ligt buiten de matrixgrenzen..

The error comes from the loop

                for(i_=1; i_<=nmip1;i_++)
                {
                    t[i_] = a[i,i_+i1_];
                }

where the i_ index runs from 0 to 25 (in the alglib svd test code) where the array is only 25 elements and start at 0 (so the index should run from 0..24).

Additional Information

Callstack:

alglib.lq.lqdecomposition(Double[,]& a, Int32 m, Int32 n, Double[]& tau) in Alglib\lq.cs: line 285

alglib.svd.svddecomposition(Double[,] a, Int32 m, Int32 n, Int32 uneeded, Int32 vtneeded, Int32 additionalmemory, Double[]& w, Double[,]& u, Double[,]& vt) in
Alglib\svd.cs: line 517

--<rest is from my test probject.
Lsa.NET.Lsa.Decompose() in C:\Documents and Settings\veg\Mijn documenten\Visual Studio 2008\Projects\Lsa\lsa\Lsa.cs: line 942
LsaTest.LsaTests.TestDecompose() in C:\Documents and Settings\veg\Mijn documenten\Visual Studio 2008\Projects\Lsa\lsatest\LsaTests.cs: line 175

As you can see I compiled and ran a vs2k8 unit test (copied the code from the alglib test into it).

Programming language

Attached Files

Relationships

Notes
(0000045) SergeyB (administrator) 2010-02-08 10:38	It is not a bug. alglib.svd.svddecomposition is an obsolete routine which uses old 1-based notation from LAPACK. It accepts matrix with [1..N,1..N] numeration, not with [0..N-1,0..N-1] indexes. It was left for backward compatibility, new users should use rmatrixsvd which uses modern 0-based array indexes. P.S. looks like it is better to purge it from next release...

Issue History
Date Modified	Username	Field	Change
2010-02-07 22:26	wvd_vegt	New Issue
2010-02-07 22:26	wvd_vegt	Programming language	=> C#
2010-02-08 10:30	SergeyB	Status	new => assigned
2010-02-08 10:30	SergeyB	Assigned To	=> SergeyB
2010-02-08 10:33	SergeyB	Category	Statistics => Linear algebra
2010-02-08 10:38	SergeyB	Note Added: 0000045
2010-02-08 10:38	SergeyB	Status	assigned => resolved
2010-02-08 10:38	SergeyB	Resolution	open => no change required

Mantis 1.1.6[^]