dlaqps(3) [debian man page]
dlaqps.f(3) LAPACK dlaqps.f(3) NAME
dlaqps.f - SYNOPSIS
Functions/Subroutines subroutine dlaqps (M, N, OFFSET, NB, KB, A, LDA, JPVT, TAU, VN1, VN2, AUXV, F, LDF) DLAQPS Function/Subroutine Documentation subroutine dlaqps (integerM, integerN, integerOFFSET, integerNB, integerKB, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, double precision, dimension( * )TAU, double precision, dimension( * )VN1, double precision, dimension( * )VN2, double precision, dimension( * )AUXV, double precision, dimension( ldf, * )F, integerLDF) DLAQPS Purpose: DLAQPS computes a step of QR factorization with column pivoting of a real 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. Parameters: M M is INTEGER The number of rows of the matrix A. M >= 0. N N is INTEGER The number of columns of the matrix A. N >= 0 OFFSET OFFSET is INTEGER The number of rows of A that have been factorized in previous steps. NB NB is INTEGER The number of columns to factorize. KB KB is INTEGER The number of columns actually factorized. A A is DOUBLE PRECISION 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. LDA LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). 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. TAU TAU is DOUBLE PRECISION array, dimension (KB) The scalar factors of the elementary reflectors. VN1 VN1 is DOUBLE PRECISION array, dimension (N) The vector with the partial column norms. VN2 VN2 is DOUBLE PRECISION array, dimension (N) The vector with the exact column norms. AUXV AUXV is DOUBLE PRECISION array, dimension (NB) Auxiliar vector. F F is DOUBLE PRECISION array, dimension (LDF,NB) Matrix F**T = L*Y**T*A. LDF LDF is INTEGER The leading dimension of the array F. LDF >= max(1,N). Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: November 2011 Contributors: G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain X. Sun, Computer Science Dept., Duke University, USA Partial column norm updating strategy modified on April 2011 Z. Drmac and Z. Bujanovic, Dept. of Mathematics, University of Zagreb, Croatia. References: LAPACK Working Note 176 Definition at line 177 of file dlaqps.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.1 Sun May 26 2013 dlaqps.f(3)
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zlaqps.f(3) LAPACK zlaqps.f(3) NAME
zlaqps.f - SYNOPSIS
Functions/Subroutines subroutine zlaqps (M, N, OFFSET, NB, KB, A, LDA, JPVT, TAU, VN1, VN2, AUXV, F, LDF) ZLAQPS Function/Subroutine Documentation subroutine zlaqps (integerM, integerN, integerOFFSET, integerNB, integerKB, complex*16, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, complex*16, dimension( * )TAU, double precision, dimension( * )VN1, double precision, dimension( * )VN2, complex*16, dimension( * )AUXV, complex*16, dimension( ldf, * )F, integerLDF) ZLAQPS Purpose: 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. Parameters: M M is INTEGER The number of rows of the matrix A. M >= 0. N N is INTEGER The number of columns of the matrix A. N >= 0 OFFSET OFFSET is INTEGER The number of rows of A that have been factorized in previous steps. NB NB is INTEGER The number of columns to factorize. KB KB is INTEGER The number of columns actually factorized. 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. LDA LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). 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. TAU TAU is COMPLEX*16 array, dimension (KB) The scalar factors of the elementary reflectors. VN1 VN1 is DOUBLE PRECISION array, dimension (N) The vector with the partial column norms. VN2 VN2 is DOUBLE PRECISION array, dimension (N) The vector with the exact column norms. AUXV AUXV is COMPLEX*16 array, dimension (NB) Auxiliar vector. F F is COMPLEX*16 array, dimension (LDF,NB) Matrix F**H = L * Y**H * A. LDF LDF is INTEGER The leading dimension of the array F. LDF >= max(1,N). Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: November 2011 Contributors: G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain X. Sun, Computer Science Dept., Duke University, USA Partial column norm updating strategy modified on April 2011 Z. Drmac and Z. Bujanovic, Dept. of Mathematics, University of Zagreb, Croatia. References: LAPACK Working Note 176 Definition at line 177 of file zlaqps.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.1 Sun May 26 2013 zlaqps.f(3)