# cgeqrs.f - Man Page

SRC/DEPRECATED/cgeqrs.f

## Synopsis

### Functions/Subroutines

subroutine **cgeqrs** (m, n, nrhs, a, lda, tau, b, ldb, work, lwork, info)**CGEQRS**

## Function/Subroutine Documentation

### subroutine cgeqrs (integer m, integer n, integer nrhs, complex, dimension( lda, * ) a, integer lda, complex, dimension( * ) tau, complex, dimension( ldb, * ) b, integer ldb, complex, dimension( lwork ) work, integer lwork, integer info)

**CGEQRS**

**Purpose:**

Solve the least squares problem min || A*X - B || using the QR factorization A = Q*R computed by CGEQRF.

**Parameters***M*M is INTEGER The number of rows of the matrix A. M >= 0.

*N*N is INTEGER The number of columns of the matrix A. M >= N >= 0.

*NRHS*NRHS is INTEGER The number of columns of B. NRHS >= 0.

*A*A is COMPLEX array, dimension (LDA,N) Details of the QR factorization of the original matrix A as returned by CGEQRF.

*LDA*LDA is INTEGER The leading dimension of the array A. LDA >= M.

*TAU*TAU is COMPLEX array, dimension (N) Details of the orthogonal matrix Q.

*B*B is COMPLEX array, dimension (LDB,NRHS) On entry, the m-by-nrhs right hand side matrix B. On exit, the n-by-nrhs solution matrix X.

*LDB*LDB is INTEGER The leading dimension of the array B. LDB >= M.

*WORK*WORK is COMPLEX array, dimension (LWORK)

*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.

*INFO*INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value

**Author**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **119** of file **cgeqrs.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page cgeqrs(3) is an alias of cgeqrs.f(3).

Tue Nov 28 2023 12:08:41 Version 3.12.0 LAPACK