cqrt17.f - Man Page

TESTING/LIN/cqrt17.f

Synopsis

Functions/Subroutines

real function cqrt17 (trans, iresid, m, n, nrhs, a, lda, x, ldx, b, ldb, c, work, lwork)
CQRT17

Function/Subroutine Documentation

real function cqrt17 (character trans, integer iresid, integer m, integer n, integer nrhs, complex, dimension( lda, * ) a, integer lda, complex, dimension( ldx, * ) x, integer ldx, complex, dimension( ldb, * ) b, integer ldb, complex, dimension( ldb, * ) c, complex, dimension( lwork ) work, integer lwork)

CQRT17

Purpose:

 CQRT17 computes the ratio

    norm(R**H * op(A)) / ( norm(A) * alpha * max(M,N,NRHS) * EPS ),

 where R = B - op(A)*X, op(A) is A or A**H, depending on TRANS, EPS
 is the machine epsilon, and

    alpha = norm(B) if IRESID = 1 (zero-residual problem)
    alpha = norm(R) if IRESID = 2 (otherwise).

 The norm used is the 1-norm.
Parameters

TRANS

          TRANS is CHARACTER*1
          Specifies whether or not the transpose of A is used.
          = 'N':  No transpose, op(A) = A.
          = 'C':  Conjugate transpose, op(A) = A**H.

IRESID

          IRESID is INTEGER
          IRESID = 1 indicates zero-residual problem.
          IRESID = 2 indicates non-zero residual.

M

          M is INTEGER
          The number of rows of the matrix A.
          If TRANS = 'N', the number of rows of the matrix B.
          If TRANS = 'C', the number of rows of the matrix X.

N

          N is INTEGER
          The number of columns of the matrix  A.
          If TRANS = 'N', the number of rows of the matrix X.
          If TRANS = 'C', the number of rows of the matrix B.

NRHS

          NRHS is INTEGER
          The number of columns of the matrices X and B.

A

          A is COMPLEX array, dimension (LDA,N)
          The m-by-n matrix A.

LDA

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

X

          X is COMPLEX array, dimension (LDX,NRHS)
          If TRANS = 'N', the n-by-nrhs matrix X.
          If TRANS = 'C', the m-by-nrhs matrix X.

LDX

          LDX is INTEGER
          The leading dimension of the array X.
          If TRANS = 'N', LDX >= N.
          If TRANS = 'C', LDX >= M.

B

          B is COMPLEX array, dimension (LDB,NRHS)
          If TRANS = 'N', the m-by-nrhs matrix B.
          If TRANS = 'C', the n-by-nrhs matrix B.

LDB

          LDB is INTEGER
          The leading dimension of the array B.
          If TRANS = 'N', LDB >= M.
          If TRANS = 'C', LDB >= N.

C

          C is COMPLEX array, dimension (LDB,NRHS)

WORK

          WORK is COMPLEX array, dimension (LWORK)

LWORK

          LWORK is INTEGER
          The length of the array WORK.  LWORK >= NRHS*(M+N).
Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 151 of file cqrt17.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page cqrt17(3) is an alias of cqrt17.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK