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LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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subroutine dgeqrs | ( | integer | m, |
integer | n, | ||
integer | nrhs, | ||
double precision, dimension( lda, * ) | a, | ||
integer | lda, | ||
double precision, dimension( * ) | tau, | ||
double precision, dimension( ldb, * ) | b, | ||
integer | ldb, | ||
double precision, dimension( lwork ) | work, | ||
integer | lwork, | ||
integer | info | ||
) |
DGEQRS
Solve the least squares problem min || A*X - B || using the QR factorization A = Q*R computed by DGEQRF.
[in] | M | M is INTEGER The number of rows of the matrix A. M >= 0. |
[in] | N | N is INTEGER The number of columns of the matrix A. M >= N >= 0. |
[in] | NRHS | NRHS is INTEGER The number of columns of B. NRHS >= 0. |
[in] | A | A is DOUBLE PRECISION array, dimension (LDA,N) Details of the QR factorization of the original matrix A as returned by DGEQRF. |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= M. |
[in] | TAU | TAU is DOUBLE PRECISION array, dimension (N) Details of the orthogonal matrix Q. |
[in,out] | B | B is DOUBLE PRECISION array, dimension (LDB,NRHS) On entry, the m-by-nrhs right hand side matrix B. On exit, the n-by-nrhs solution matrix X. |
[in] | LDB | LDB is INTEGER The leading dimension of the array B. LDB >= M. |
[out] | WORK | WORK is DOUBLE PRECISION array, dimension (LWORK) |
[in] | LWORK | LWORK is INTEGER The length of the array WORK. LWORK must be at least NRHS, and should be at least NRHS*NB, where NB is the block size for this environment. |
[out] | INFO | INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value |
Definition at line 119 of file dgeqrs.f.