PLASMA  2.8.0
PLASMA - Parallel Linear Algebra for Scalable Multi-core Architectures
int PLASMA_zcgels_Tile ( PLASMA_enum  trans,
PLASMA_desc A,
PLASMA_desc T,
PLASMA_desc B,
PLASMA_desc X,
int *  ITER 
)

PLASMA_zcgels_Tile - Solves overdetermined or underdetermined linear system of equations using the tile QR or the tile LQ factorization and mixed-precision iterative refinement. Tile equivalent of PLASMA_zcgesv(). Operates on matrices stored by tiles. All matrices are passed through descriptors. All dimensions are taken from the descriptors.

Parameters
[in]transIntended usage: = PlasmaNoTrans: the linear system involves A; = PlasmaConjTrans: the linear system involves A**H. Currently only PlasmaNoTrans is supported.
[in,out]A
  • If the iterative refinement converged, A is not modified;
  • otherwise, it fell back to double precision solution, and on exit the M-by-N matrix A contains: if M >= N, A is overwritten by details of its QR factorization as returned by PLASMA_zgeqrf; if M < N, A is overwritten by details of its LQ factorization as returned by PLASMA_zgelqf.
[out]TOn exit:
  • if the iterative refinement converged, T is not modified;
  • otherwise, it fell back to double precision solution, and then T is an auxiliary factorization data.
[in,out]BOn 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]BThe descriptor of the M-by-NRHS matrix B of right hand side vectors, stored columnwise. Not modified.
[in,out]XOn entry, it's only the descriptor where to store the result. On exit, if return value = 0, X is the solution vectors, stored columnwise: if M >= N, rows 1 to N of X 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 X contain the minimum norm solution vectors;
[out]ITERIf > 0, ITER is the number of the current iteration in the iterative refinement process. -ITERMAX-1, if the refinment step failed and the double precision factorization has been used.
Returns
Return values
PLASMA_SUCCESSsuccessful exit
See also
PLASMA_zcgels
PLASMA_zcgels_Tile_Async
PLASMA_dsgels_Tile
PLASMA_zgels_Tile