ML_DGELQF – Computes an LQ factorization of a real M-by-N matrix A

Block SymbolLicensing group: MATRIX

Function Description
The output references yA, yTAU and yWORK are always set to the corresponding input references uA, uTAU and uWORK. If HLD = on then nothing is computed otherwise the LAPACK function DGELQF is called internally:

DGELQF(M, N, uA, LDA, uTAU, uWORK, LWORK, info);

where parameters of DGELQF are set in the following way:

M is number of rows of the matrix referenced by uA.
N is number of columns of the matrix referenced by uA.
LDA is the leading dimension of the matrix referenced by uA.
LWORK is number of elements of the vector referenced by uWORK.
info is return code from the function DGELQF.

The error flag E is set to on if:

the reference uA or uTAU or uWORK is not defined (i.e. input uA or uTAU or uWORK is not connected),
number of elements of the vector referenced by uTAU is less than the minimum of number of rows and number of columns of the matrix referenced by uA.
the call of the function DGELQF returns error using the function XERBLA, see the return code info and system log.

See LAPACK documentation [8] for more details.

Inputs

uA	Input reference to matrix A	Reference
uTAU	Input reference to vector of scalar factors of the elementary reflectors	Reference
uWORK	Input reference to working vector WORK	Reference
HLD	Hold	Bool

Outputs

yA	Output reference to matrix A	Reference
yTAU	Output reference to vector of scalar factors of the elementary reflectors	Reference
yWORK	Output reference to working vector WORK	Reference
E	Error indicator	Bool
info	LAPACK function result info. If info = -i, the i=th argument had an illegal value	Long (I32)

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