GNU Octave - Bugs: bug #57475, svds warns about ill-condition...

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bug #57475: svds warns about ill-condition input with NaNs rather than issuing error

Submitter:	CH <atcl>
Submitted:	Wed 25 Dec 2019 10:12:57 AM UTC


Category:	Octave Function	Severity:	3 - Normal
Priority:	5 - Normal	Item Group:	Missed Error or Warning
Status:	Confirmed	Assigned to:	None
Originator Name:		Open/Closed: *	Open
Release: *	dev	Operating System: *	Any
Fixed Release:	None	Planned Release:	None

* Mandatory Fields

Add a New Comment Rich Markup

Thu 26 Dec 2019 06:46:53 PM UTC, comment #1:

For reference, the behavior on the development version of Octave which is about to become version 6.1 is a little less scary:

x = svds(nan*ones(3),2)
warning: svds: returning fewer singular values than requested
warning: called from
svds at line 230 column 7

x = [](0x1)

Still, it would be better if the warning message was more precise about the problem (NaN). For reference, Matlab issues the same error for either of your examples (badly-conditioned matrix with Info or NaN present).

Rik <rik5>

Wed 25 Dec 2019 10:12:57 AM UTC, original submission:

Calling svds on NaN matrix requesting a set number of singular values less than largest dimension of the argument matrix returns:

svds(nan*ones(3),2)
DLASCL: parameter number 4 is invalid
error: Fortran procedure terminated by call to XERBLA
error: called from
eigs at line 285 column 20
svds at line 187 column 9

while requesting all singular values gives:

svds(nan*ones(3),3)
error: eig: EIG: matrix contains Inf or NaN values
error: called from
eigs at line 277 column 22
svds at line 187 column 9

Does the first error messagee need to be fixed?

Best

CH <atcl>

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Follow 3 latest changes.

Date	Changed by	Updated Field	Previous Value	Replaced by
2019-12-26	rik5	Status	None	Confirmed
		Release	5.1.0	dev
		Summary	svds returns unusual error	svds warns about ill-condition input with NaNs rather than issuing error

GNU Octave - Bugs: bug #57475, svds warns about ill-condition...

bug #57475: svds warns about ill-condition input with NaNs rather than issuing error

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