trti2(3)

NAME
trti2 - trti2: triangular inverse, level 2

SYNOPSIS

  Functions
subroutine ctrti2 (uplo, diag, n, a, lda, info)
CTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).
subroutine dtrti2 (uplo, diag, n, a, lda, info)
DTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).
subroutine strti2 (uplo, diag, n, a, lda, info)
STRTI2 computes the inverse of a triangular matrix (unblocked algorithm).
subroutine ztrti2 (uplo, diag, n, a, lda, info)
ZTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Detailed Description

Function Documentation

  subroutine ctrti2 (character uplo, character diag, integer n, complex, dimension( lda, * ) a, integer lda, integer info)

CTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Purpose:

    !>
    !> CTRTI2 computes the inverse of a complex upper or lower triangular
    !> matrix.
    !>
    !> This is the Level 2 BLAS version of the algorithm.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>          Specifies whether the matrix A is upper or lower triangular.
    !>          = 'U':  Upper triangular
    !>          = 'L':  Lower triangular
    !>

    DIAG

    !>          DIAG is CHARACTER*1
    !>          Specifies whether or not the matrix A is unit triangular.
    !>          = 'N':  Non-unit triangular
    !>          = 'U':  Unit triangular
    !>

    N

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

    A

    !>          A is COMPLEX array, dimension (LDA,N)
    !>          On entry, the triangular matrix A.  If UPLO = 'U', the
    !>          leading n by n upper triangular part of the array A contains
    !>          the upper triangular matrix, and the strictly lower
    !>          triangular part of A is not referenced.  If UPLO = 'L', the
    !>          leading n by n lower triangular part of the array A contains
    !>          the lower triangular matrix, and the strictly upper
    !>          triangular part of A is not referenced.  If DIAG = 'U', the
    !>          diagonal elements of A are also not referenced and are
    !>          assumed to be 1.
    !>
    !>          On exit, the (triangular) inverse of the original matrix, in
    !>          the same storage format.
    !>

    LDA

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

    INFO

    !>          INFO is INTEGER
    !>          = 0: successful exit
    !>          < 0: if INFO = -k, the k-th argument had an illegal value
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 109 of file ctrti2.f.

  subroutine dtrti2 (character uplo, character diag, integer n, double precision, dimension( lda, * ) a, integer lda, integer info)

DTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Purpose:

    !>
    !> DTRTI2 computes the inverse of a real upper or lower triangular
    !> matrix.
    !>
    !> This is the Level 2 BLAS version of the algorithm.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>          Specifies whether the matrix A is upper or lower triangular.
    !>          = 'U':  Upper triangular
    !>          = 'L':  Lower triangular
    !>

    DIAG

    !>          DIAG is CHARACTER*1
    !>          Specifies whether or not the matrix A is unit triangular.
    !>          = 'N':  Non-unit triangular
    !>          = 'U':  Unit triangular
    !>

    N

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

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA,N)
    !>          On entry, the triangular matrix A.  If UPLO = 'U', the
    !>          leading n by n upper triangular part of the array A contains
    !>          the upper triangular matrix, and the strictly lower
    !>          triangular part of A is not referenced.  If UPLO = 'L', the
    !>          leading n by n lower triangular part of the array A contains
    !>          the lower triangular matrix, and the strictly upper
    !>          triangular part of A is not referenced.  If DIAG = 'U', the
    !>          diagonal elements of A are also not referenced and are
    !>          assumed to be 1.
    !>
    !>          On exit, the (triangular) inverse of the original matrix, in
    !>          the same storage format.
    !>

    LDA

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

    INFO

    !>          INFO is INTEGER
    !>          = 0: successful exit
    !>          < 0: if INFO = -k, the k-th argument had an illegal value
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 109 of file dtrti2.f.

  subroutine strti2 (character uplo, character diag, integer n, real, dimension( lda, * ) a, integer lda, integer info)

STRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Purpose:

    !>
    !> STRTI2 computes the inverse of a real upper or lower triangular
    !> matrix.
    !>
    !> This is the Level 2 BLAS version of the algorithm.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>          Specifies whether the matrix A is upper or lower triangular.
    !>          = 'U':  Upper triangular
    !>          = 'L':  Lower triangular
    !>

    DIAG

    !>          DIAG is CHARACTER*1
    !>          Specifies whether or not the matrix A is unit triangular.
    !>          = 'N':  Non-unit triangular
    !>          = 'U':  Unit triangular
    !>

    N

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

    A

    !>          A is REAL array, dimension (LDA,N)
    !>          On entry, the triangular matrix A.  If UPLO = 'U', the
    !>          leading n by n upper triangular part of the array A contains
    !>          the upper triangular matrix, and the strictly lower
    !>          triangular part of A is not referenced.  If UPLO = 'L', the
    !>          leading n by n lower triangular part of the array A contains
    !>          the lower triangular matrix, and the strictly upper
    !>          triangular part of A is not referenced.  If DIAG = 'U', the
    !>          diagonal elements of A are also not referenced and are
    !>          assumed to be 1.
    !>
    !>          On exit, the (triangular) inverse of the original matrix, in
    !>          the same storage format.
    !>

    LDA

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

    INFO

    !>          INFO is INTEGER
    !>          = 0: successful exit
    !>          < 0: if INFO = -k, the k-th argument had an illegal value
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 109 of file strti2.f.

  subroutine ztrti2 (character uplo, character diag, integer n, complex*16, dimension( lda, * ) a, integer lda, integer info)

ZTRTI2 computes the inverse of a triangular matrix (unblocked algorithm).

Purpose:

    !>
    !> ZTRTI2 computes the inverse of a complex upper or lower triangular
    !> matrix.
    !>
    !> This is the Level 2 BLAS version of the algorithm.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>          Specifies whether the matrix A is upper or lower triangular.
    !>          = 'U':  Upper triangular
    !>          = 'L':  Lower triangular
    !>

    DIAG

    !>          DIAG is CHARACTER*1
    !>          Specifies whether or not the matrix A is unit triangular.
    !>          = 'N':  Non-unit triangular
    !>          = 'U':  Unit triangular
    !>

    N

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

    A

    !>          A is COMPLEX*16 array, dimension (LDA,N)
    !>          On entry, the triangular matrix A.  If UPLO = 'U', the
    !>          leading n by n upper triangular part of the array A contains
    !>          the upper triangular matrix, and the strictly lower
    !>          triangular part of A is not referenced.  If UPLO = 'L', the
    !>          leading n by n lower triangular part of the array A contains
    !>          the lower triangular matrix, and the strictly upper
    !>          triangular part of A is not referenced.  If DIAG = 'U', the
    !>          diagonal elements of A are also not referenced and are
    !>          assumed to be 1.
    !>
    !>          On exit, the (triangular) inverse of the original matrix, in
    !>          the same storage format.
    !>

    LDA

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

    INFO

    !>          INFO is INTEGER
    !>          = 0: successful exit
    !>          < 0: if INFO = -k, the k-th argument had an illegal value
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 109 of file ztrti2.f.

Author

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