Computes a step of QR factorization with column pivoting of a real
nmatrix A by using BLAS level 3.
The routine computes a step of
QRfactorization with column pivoting of a real
Aby using BLAS level 3. The routine tries to factorize
Astarting from the row
offset+1, and updates all of the matrix with BLAS level 3 routine
In some cases, due to catastrophic cancellations,
NBcolumns. Hence, the actual number of factorized columns is returned in
is accordingly pivoted, but not factorized.
- INTEGER. The number of rows of the matrixA..m≥0
- INTEGER. The number of columns of the matrixA..n≥0
- INTEGER. The number of rows ofAthat have been factorized in previous steps.
- INTEGER. The number of columns to factorize.
- REALforslaqpsDOUBLE PRECISIONfordlaqpsCOMPLEXforclaqpsDOUBLE COMPLEXforzlaqpsArray,DIMENSION(lda,n).On entry, them-by-nmatrixA.
- INTEGER. The leading dimension of the arraya.lda