0000293: SVD Algorithhm crashes on array bounds

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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

Platform

Status

resolved

Projection

none

OS Version

ETA

none

Fixed in Version

Product Version

2.3.0

Target Version

Product Build

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).

Steps To Reproduce

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

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