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MAGMA
1.5.0
Matrix Algebra for GPU and Multicore Architectures
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Functions | |
magma_int_t | magma_dgeqp3 (magma_int_t m, magma_int_t n, double *A, magma_int_t lda, magma_int_t *jpvt, double *tau, double *work, magma_int_t lwork, magma_int_t *info) |
DGEQP3 computes a QR factorization with column pivoting of a matrix A: A*P = Q*R using Level 3 BLAS. More... | |
magma_int_t | magma_dgeqp3_gpu (magma_int_t m, magma_int_t n, double *dA, magma_int_t ldda, magma_int_t *jpvt, double *tau, double *dwork, magma_int_t lwork, magma_int_t *info) |
DGEQP3 computes a QR factorization with column pivoting of a matrix A: A*P = Q*R using Level 3 BLAS. More... | |
magma_int_t magma_dgeqp3 | ( | magma_int_t | m, |
magma_int_t | n, | ||
double * | A, | ||
magma_int_t | lda, | ||
magma_int_t * | jpvt, | ||
double * | tau, | ||
double * | work, | ||
magma_int_t | lwork, | ||
magma_int_t * | info | ||
) |
DGEQP3 computes a QR factorization with column pivoting of a matrix A: A*P = Q*R using Level 3 BLAS.
[in] | m | INTEGER The number of rows of the matrix A. M >= 0. |
[in] | n | INTEGER The number of columns of the matrix A. N >= 0. |
[in,out] | A | DOUBLE_PRECISION array, dimension (LDA,N) On entry, the M-by-N matrix A. On exit, the upper triangle of the array contains the min(M,N)-by-N upper trapezoidal matrix R; the elements below the diagonal, together with the array TAU, represent the unitary matrix Q as a product of min(M,N) elementary reflectors. |
[in] | lda | INTEGER The leading dimension of the array A. LDA >= max(1,M). |
[in,out] | jpvt | INTEGER array, dimension (N) On entry, if JPVT(J).ne.0, the J-th column of A is permuted to the front of A*P (a leading column); if JPVT(J)=0, the J-th column of A is a free column. On exit, if JPVT(J)=K, then the J-th column of A*P was the the K-th column of A. |
[out] | tau | DOUBLE_PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors. |
[out] | work | (workspace) DOUBLE_PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO=0, WORK(1) returns the optimal LWORK. |
[in] | lwork | INTEGER The dimension of the array WORK. For [sd]geqp3, LWORK >= (N+1)*NB + 2*N; for [cz]geqp3, LWORK >= (N+1)*NB, where NB is the optimal blocksize. If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA. |
rwork | (workspace, for [cz]geqp3 only) DOUBLE PRECISION array, dimension (2*N) | |
[out] | info | INTEGER
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The matrix Q is represented as a product of elementary reflectors
Q = H(1) H(2) . . . H(k), where k = min(m,n).
Each H(i) has the form
H(i) = I - tau * v * v'
where tau is a real scalar, and v is a real vector with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i), and tau in TAU(i).
magma_int_t magma_dgeqp3_gpu | ( | magma_int_t | m, |
magma_int_t | n, | ||
double * | dA, | ||
magma_int_t | ldda, | ||
magma_int_t * | jpvt, | ||
double * | tau, | ||
double * | dwork, | ||
magma_int_t | lwork, | ||
magma_int_t * | info | ||
) |
DGEQP3 computes a QR factorization with column pivoting of a matrix A: A*P = Q*R using Level 3 BLAS.
[in] | m | INTEGER The number of rows of the matrix A. M >= 0. |
[in] | n | INTEGER The number of columns of the matrix A. N >= 0. |
[in,out] | dA | DOUBLE_PRECISION array on the GPU, dimension (LDDA,N) On entry, the M-by-N matrix A. On exit, the upper triangle of the array contains the min(M,N)-by-N upper trapezoidal matrix R; the elements below the diagonal, together with the array TAU, represent the unitary matrix Q as a product of min(M,N) elementary reflectors. |
[in] | ldda | INTEGER The leading dimension of the array A. LDDA >= max(1,M). |
[in,out] | jpvt | INTEGER array, dimension (N) On entry, if JPVT(J).ne.0, the J-th column of A is permuted to the front of A*P (a leading column); if JPVT(J)=0, the J-th column of A is a free column. On exit, if JPVT(J)=K, then the J-th column of A*P was the the K-th column of A. |
[out] | tau | DOUBLE_PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors. |
[out] | dwork | (workspace) DOUBLE_PRECISION array on the GPU, dimension (MAX(1,LWORK)) On exit, if INFO=0, WORK(1) returns the optimal LWORK. |
[in] | lwork | INTEGER The dimension of the array WORK. For [sd]geqp3, LWORK >= (N+1)*NB + 2*N; for [cz]geqp3, LWORK >= (N+1)*NB, where NB is the optimal blocksize. If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA. |
rwork | (workspace, for [cz]geqp3 only) DOUBLE PRECISION array, dimension (2*N) | |
[out] | info | INTEGER
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The matrix Q is represented as a product of elementary reflectors
Q = H(1) H(2) . . . H(k), where k = min(m,n).
Each H(i) has the form
H(i) = I - tau * v * v'
where tau is a real scalar, and v is a real vector with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i), and tau in TAU(i).