LAPACK
3.6.1
LAPACK: Linear Algebra PACKage
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subroutine zlaqps | ( | integer | M, |
integer | N, | ||
integer | OFFSET, | ||
integer | NB, | ||
integer | KB, | ||
complex*16, dimension( lda, * ) | A, | ||
integer | LDA, | ||
integer, dimension( * ) | JPVT, | ||
complex*16, dimension( * ) | TAU, | ||
double precision, dimension( * ) | VN1, | ||
double precision, dimension( * ) | VN2, | ||
complex*16, dimension( * ) | AUXV, | ||
complex*16, dimension( ldf, * ) | F, | ||
integer | LDF | ||
) |
ZLAQPS computes a step of QR factorization with column pivoting of a real m-by-n matrix A by using BLAS level 3.
Download ZLAQPS + dependencies [TGZ] [ZIP] [TXT]
ZLAQPS computes a step of QR factorization with column pivoting of a complex M-by-N matrix A by using Blas-3. It tries to factorize NB columns from A starting from the row OFFSET+1, and updates all of the matrix with Blas-3 xGEMM. In some cases, due to catastrophic cancellations, it cannot factorize NB columns. Hence, the actual number of factorized columns is returned in KB. Block A(1:OFFSET,1:N) is accordingly pivoted, but not factorized.
[in] | M | M is INTEGER The number of rows of the matrix A. M >= 0. |
[in] | N | N is INTEGER The number of columns of the matrix A. N >= 0 |
[in] | OFFSET | OFFSET is INTEGER The number of rows of A that have been factorized in previous steps. |
[in] | NB | NB is INTEGER The number of columns to factorize. |
[out] | KB | KB is INTEGER The number of columns actually factorized. |
[in,out] | A | A is COMPLEX*16 array, dimension (LDA,N) On entry, the M-by-N matrix A. On exit, block A(OFFSET+1:M,1:KB) is the triangular factor obtained and block A(1:OFFSET,1:N) has been accordingly pivoted, but no factorized. The rest of the matrix, block A(OFFSET+1:M,KB+1:N) has been updated. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). |
[in,out] | JPVT | JPVT is INTEGER array, dimension (N) JPVT(I) = K <==> Column K of the full matrix A has been permuted into position I in AP. |
[out] | TAU | TAU is COMPLEX*16 array, dimension (KB) The scalar factors of the elementary reflectors. |
[in,out] | VN1 | VN1 is DOUBLE PRECISION array, dimension (N) The vector with the partial column norms. |
[in,out] | VN2 | VN2 is DOUBLE PRECISION array, dimension (N) The vector with the exact column norms. |
[in,out] | AUXV | AUXV is COMPLEX*16 array, dimension (NB) Auxiliar vector. |
[in,out] | F | F is COMPLEX*16 array, dimension (LDF,NB) Matrix F**H = L * Y**H * A. |
[in] | LDF | LDF is INTEGER The leading dimension of the array F. LDF >= max(1,N). |
Definition at line 179 of file zlaqps.f.