PLASMA
2.8.0
PLASMA - Parallel Linear Algebra for Scalable Multi-core Architectures
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int PLASMA_cgels | ( | PLASMA_enum | trans, |
int | M, | ||
int | N, | ||
int | NRHS, | ||
PLASMA_Complex32_t * | A, | ||
int | LDA, | ||
PLASMA_desc * | descT, | ||
PLASMA_Complex32_t * | B, | ||
int | LDB | ||
) |
PLASMA_cgels - solves overdetermined or underdetermined linear systems involving an M-by-N matrix A using the QR or the LQ factorization of A. It is assumed that A has full rank. The following options are provided:
overdetermined system, i.e., solve the least squares problem: minimize || B - A*X ||.
underdetermined system A * X = B.
Several right hand side vectors B and solution vectors X can be handled in a single call; they are stored as the columns of the M-by-NRHS right hand side matrix B and the N-by-NRHS solution matrix X.
[in] | trans | Intended usage: = PlasmaNoTrans: the linear system involves A; = PlasmaConjTrans: the linear system involves A**H. Currently only PlasmaNoTrans is supported. |
[in] | M | The number of rows of the matrix A. M >= 0. |
[in] | N | The number of columns of the matrix A. N >= 0. |
[in] | NRHS | The number of right hand sides, i.e., the number of columns of the matrices B and X. NRHS >= 0. |
[in,out] | A | On entry, the M-by-N matrix A. On exit, if M >= N, A is overwritten by details of its QR factorization as returned by PLASMA_cgeqrf; if M < N, A is overwritten by details of its LQ factorization as returned by PLASMA_cgelqf. |
[in] | LDA | The leading dimension of the array A. LDA >= max(1,M). |
[out] | descT | On exit, auxiliary factorization data. |
[in,out] | B | On entry, the M-by-NRHS matrix B of right hand side vectors, stored columnwise; On exit, if return value = 0, B is overwritten by the solution vectors, stored columnwise: if M >= N, rows 1 to N of B contain the least squares solution vectors; the residual sum of squares for the solution in each column is given by the sum of squares of the modulus of elements N+1 to M in that column; if M < N, rows 1 to N of B contain the minimum norm solution vectors; |
[in] | LDB | The leading dimension of the array B. LDB >= MAX(1,M,N). |
PLASMA_SUCCESS | successful exit |
<0 | if -i, the i-th argument had an illegal value |