getrs(3)

NAME
getrs - getrs: triangular solve using factor

SYNOPSIS

  Functions
subroutine cgetrs (trans, n, nrhs, a, lda, ipiv, b, ldb, info)
CGETRS
subroutine dgetrs (trans, n, nrhs, a, lda, ipiv, b, ldb, info)
DGETRS
subroutine sgetrs (trans, n, nrhs, a, lda, ipiv, b, ldb, info)
SGETRS
subroutine zgetrs (trans, n, nrhs, a, lda, ipiv, b, ldb, info)
ZGETRS

Detailed Description

Function Documentation

  subroutine cgetrs (character trans, integer n, integer nrhs, complex, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, complex, dimension( ldb, * ) b, integer ldb, integer info)

CGETRS

Purpose:

     CGETRS solves a system of linear equations
        A * X = B,  A**T * X = B,  or  A**H * X = B
     with a general N-by-N matrix A using the LU factorization computed
     by CGETRF.

Parameters
    TRANS

              TRANS is CHARACTER*1
              Specifies the form of the system of equations:
              = 'N':  A * X = B     (No transpose)
              = 'T':  A**T * X = B  (Transpose)
              = 'C':  A**H * X = B  (Conjugate transpose)

    N

              N is INTEGER
              The order of the matrix A.  N >= 0.

    NRHS

              NRHS is INTEGER
              The number of right hand sides, i.e., the number of columns
              of the matrix B.  NRHS >= 0.

    A

              A is COMPLEX array, dimension (LDA,N)
              The factors L and U from the factorization A = P*L*U
              as computed by CGETRF.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,N).

    IPIV

              IPIV is INTEGER array, dimension (N)
              The pivot indices from CGETRF; for 1<=i<=N, row i of the
              matrix was interchanged with row IPIV(i).

    B

              B is COMPLEX array, dimension (LDB,NRHS)
              On entry, the right hand side matrix B.
              On exit, the solution matrix X.

    LDB

              LDB is INTEGER
              The leading dimension of the array B.  LDB >= max(1,N).

    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 120 of file cgetrs.f.

  subroutine dgetrs (character trans, integer n, integer nrhs, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision, dimension( ldb, * ) b, integer ldb, integer info)

DGETRS

Purpose:

     DGETRS solves a system of linear equations
        A * X = B  or  A**T * X = B
     with a general N-by-N matrix A using the LU factorization computed
     by DGETRF.

Parameters
    TRANS

              TRANS is CHARACTER*1
              Specifies the form of the system of equations:
              = 'N':  A * X = B  (No transpose)
              = 'T':  A**T* X = B  (Transpose)
              = 'C':  A**T* X = B  (Conjugate transpose = Transpose)

    N

              N is INTEGER
              The order of the matrix A.  N >= 0.

    NRHS

              NRHS is INTEGER
              The number of right hand sides, i.e., the number of columns
              of the matrix B.  NRHS >= 0.

    A

              A is DOUBLE PRECISION array, dimension (LDA,N)
              The factors L and U from the factorization A = P*L*U
              as computed by DGETRF.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,N).

    IPIV

              IPIV is INTEGER array, dimension (N)
              The pivot indices from DGETRF; for 1<=i<=N, row i of the
              matrix was interchanged with row IPIV(i).

    B

              B is DOUBLE PRECISION array, dimension (LDB,NRHS)
              On entry, the right hand side matrix B.
              On exit, the solution matrix X.

    LDB

              LDB is INTEGER
              The leading dimension of the array B.  LDB >= max(1,N).

    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 120 of file dgetrs.f.

  subroutine sgetrs (character trans, integer n, integer nrhs, real, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, real, dimension( ldb, * ) b, integer ldb, integer info)

SGETRS

Purpose:

     SGETRS solves a system of linear equations
        A * X = B  or  A**T * X = B
     with a general N-by-N matrix A using the LU factorization computed
     by SGETRF.

Parameters
    TRANS

              TRANS is CHARACTER*1
              Specifies the form of the system of equations:
              = 'N':  A * X = B  (No transpose)
              = 'T':  A**T* X = B  (Transpose)
              = 'C':  A**T* X = B  (Conjugate transpose = Transpose)

    N

              N is INTEGER
              The order of the matrix A.  N >= 0.

    NRHS

              NRHS is INTEGER
              The number of right hand sides, i.e., the number of columns
              of the matrix B.  NRHS >= 0.

    A

              A is REAL array, dimension (LDA,N)
              The factors L and U from the factorization A = P*L*U
              as computed by SGETRF.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,N).

    IPIV

              IPIV is INTEGER array, dimension (N)
              The pivot indices from SGETRF; for 1<=i<=N, row i of the
              matrix was interchanged with row IPIV(i).

    B

              B is REAL array, dimension (LDB,NRHS)
              On entry, the right hand side matrix B.
              On exit, the solution matrix X.

    LDB

              LDB is INTEGER
              The leading dimension of the array B.  LDB >= max(1,N).

    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 120 of file sgetrs.f.

  subroutine zgetrs (character trans, integer n, integer nrhs, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, complex*16, dimension( ldb, * ) b, integer ldb, integer info)

ZGETRS

Purpose:

     ZGETRS solves a system of linear equations
        A * X = B,  A**T * X = B,  or  A**H * X = B
     with a general N-by-N matrix A using the LU factorization computed
     by ZGETRF.

Parameters
    TRANS

              TRANS is CHARACTER*1
              Specifies the form of the system of equations:
              = 'N':  A * X = B     (No transpose)
              = 'T':  A**T * X = B  (Transpose)
              = 'C':  A**H * X = B  (Conjugate transpose)

    N

              N is INTEGER
              The order of the matrix A.  N >= 0.

    NRHS

              NRHS is INTEGER
              The number of right hand sides, i.e., the number of columns
              of the matrix B.  NRHS >= 0.

    A

              A is COMPLEX*16 array, dimension (LDA,N)
              The factors L and U from the factorization A = P*L*U
              as computed by ZGETRF.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,N).

    IPIV

              IPIV is INTEGER array, dimension (N)
              The pivot indices from ZGETRF; for 1<=i<=N, row i of the
              matrix was interchanged with row IPIV(i).

    B

              B is COMPLEX*16 array, dimension (LDB,NRHS)
              On entry, the right hand side matrix B.
              On exit, the solution matrix X.

    LDB

              LDB is INTEGER
              The leading dimension of the array B.  LDB >= max(1,N).

    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 120 of file zgetrs.f.

Author

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