ML_DGEBRD – Reduces a general real matrix to bidiagonal form by an orthogonal transformation

Block SymbolLicensing group: MATRIX

Function Description
The output references yA, yD, yE, yTAUQ, yTAUP and yWORK are always set to the corresponding input references uA, uD, uE, uTAUQ, uTAUP and uWORK. If HLD = on then nothing is computed otherwise the LAPACK function DGEBRD is called internally:

DGEBRD(M, N, uA, LDA, uD, uE, uTAUQ, uTAUP, uWORK, info);

where parameters of DGEBRD 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.
info is return code from the function DGEBRD.

The error flag E is set to on if:

the reference uA or uD or uE or uTAUQ or uTAUP or uWORK is not defined (i.e. input uA or uD or uE or uTAUQ or uTAUP or uWORK is not connected),
number of elements of any vector referenced by uD, uTAUQ and uTAUP is less than MINMN, where MINMN is minimum from M and N,
number of elements of the vector referenced by uE is less than $MINMN - 1$ ,
the call of the function DGEBRD returns error using the function XERBLA, see the return code info and system log.

See LAPACK documentation [10] for more details.

This block does not propagate the signal quality. More information can be found in the 1.4 section.

Input

uA	Input reference to matrix A	Reference
uD	Diagonal elements of the bidiagonal matrix B	Reference
uE	Off-diagonal elements of the bidiagonal matrix B	Reference
uTAUQ	Reference to a vector of scalar factors of the elementary reflectors which represent the orthogonal matrix Q	Reference
uTAUP	Reference to a vector of scalar factors of the elementary reflectors which represent the orthogonal matrix P	Reference
uWORK	Input reference to working vector WORK	Reference
HLD	Hold	Bool

Output

yA	Output reference to matrix A	Reference
yD	Output reference to D	Reference
yE	Output reference to E	Reference
yTAUQ	Output reference to TAUQ	Reference
yTAUP	Output reference to TAUP	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)

[Previous] [Back to top] [Up] [Next]