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MAGMA
1.5.0
Matrix Algebra for GPU and Multicore Architectures
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Functions | |
magma_int_t | magma_dgelqf (magma_int_t m, magma_int_t n, double *A, magma_int_t lda, double *tau, double *work, magma_int_t lwork, magma_int_t *info) |
DGELQF computes an LQ factorization of a DOUBLE_PRECISION M-by-N matrix A: A = L * Q. More... | |
magma_int_t | magma_dgelqf_gpu (magma_int_t m, magma_int_t n, double *dA, magma_int_t lda, double *tau, double *work, magma_int_t lwork, magma_int_t *info) |
DGELQF computes an LQ factorization of a DOUBLE_PRECISION M-by-N matrix dA: dA = L * Q. More... | |
magma_int_t magma_dgelqf | ( | magma_int_t | m, |
magma_int_t | n, | ||
double * | A, | ||
magma_int_t | lda, | ||
double * | tau, | ||
double * | work, | ||
magma_int_t | lwork, | ||
magma_int_t * | info | ||
) |
DGELQF computes an LQ factorization of a DOUBLE_PRECISION M-by-N matrix A: A = L * Q.
[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 elements on and below the diagonal of the array contain the m-by-min(m,n) lower trapezoidal matrix L (L is lower triangular if m <= n); the elements above the diagonal, with the array TAU, represent the orthogonal matrix Q as a product of elementary reflectors (see Further Details). Higher performance is achieved if A is in pinned memory, e.g. allocated using magma_malloc_pinned. |
[in] | lda | INTEGER The leading dimension of the array A. LDA >= max(1,M). |
[out] | tau | DOUBLE_PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors (see Further Details). |
[out] | work | (workspace) DOUBLE_PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. Higher performance is achieved if WORK is in pinned memory, e.g. allocated using magma_malloc_pinned. |
[in] | lwork | INTEGER The dimension of the array WORK. LWORK >= max(1,M). For optimum performance LWORK >= M*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. |
[out] | info | INTEGER
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The matrix Q is represented as a product of elementary reflectors
Q = H(k) . . . H(2) H(1), 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:n) is stored on exit in A(i,i+1:n), and tau in TAU(i).
magma_int_t magma_dgelqf_gpu | ( | magma_int_t | m, |
magma_int_t | n, | ||
double * | dA, | ||
magma_int_t | lda, | ||
double * | tau, | ||
double * | work, | ||
magma_int_t | lwork, | ||
magma_int_t * | info | ||
) |
DGELQF computes an LQ factorization of a DOUBLE_PRECISION M-by-N matrix dA: dA = L * Q.
[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 (LDA,N) On entry, the M-by-N matrix dA. On exit, the elements on and below the diagonal of the array contain the m-by-min(m,n) lower trapezoidal matrix L (L is lower triangular if m <= n); the elements above the diagonal, with the array TAU, represent the orthogonal matrix Q as a product of elementary reflectors (see Further Details). |
[in] | lda | INTEGER The leading dimension of the array dA. LDA >= max(1,M). |
[out] | tau | DOUBLE_PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors (see Further Details). |
[out] | work | (workspace) DOUBLE_PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. Higher performance is achieved if WORK is in pinned memory, e.g. allocated using magma_malloc_pinned. |
[in] | lwork | INTEGER The dimension of the array WORK. LWORK >= max(1,M). For optimum performance LWORK >= M*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. |
[out] | info | INTEGER
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The matrix Q is represented as a product of elementary reflectors
Q = H(k) . . . H(2) H(1), 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:n) is stored on exit in A(i,i+1:n), and tau in TAU(i).