tbmv(3)

NAME
tbmv - tbmv: triangular matrix-vector multiply

SYNOPSIS

  Functions
subroutine ctbmv (uplo, trans, diag, n, k, a, lda, x, incx)
CTBMV
subroutine dtbmv (uplo, trans, diag, n, k, a, lda, x, incx)
DTBMV
subroutine stbmv (uplo, trans, diag, n, k, a, lda, x, incx)
STBMV
subroutine ztbmv (uplo, trans, diag, n, k, a, lda, x, incx)
ZTBMV

Detailed Description

Function Documentation

  subroutine ctbmv (character uplo, character trans, character diag, integer n, integer k, complex, dimension(lda,*) a, integer lda, complex, dimension(*) x, integer incx)

CTBMV

Purpose:

     CTBMV  performs one of the matrix-vector operations
        x := A*x,   or   x := A**T*x,   or   x := A**H*x,
     where x is an n element vector and  A is an n by n unit, or non-unit,
     upper or lower triangular band matrix, with ( k + 1 ) diagonals.

Parameters
    UPLO

              UPLO is CHARACTER*1
               On entry, UPLO specifies whether the matrix is an upper or
               lower triangular matrix as follows:
                  UPLO = 'U' or 'u'   A is an upper triangular matrix.
                  UPLO = 'L' or 'l'   A is a lower triangular matrix.

    TRANS

              TRANS is CHARACTER*1
               On entry, TRANS specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'   x := A*x.
                  TRANS = 'T' or 't'   x := A**T*x.
                  TRANS = 'C' or 'c'   x := A**H*x.

    DIAG

              DIAG is CHARACTER*1
               On entry, DIAG specifies whether or not A is unit
               triangular as follows:
                  DIAG = 'U' or 'u'   A is assumed to be unit triangular.
                  DIAG = 'N' or 'n'   A is not assumed to be unit
                                      triangular.

    N

              N is INTEGER
               On entry, N specifies the order of the matrix A.
               N must be at least zero.

    K

              K is INTEGER
               On entry with UPLO = 'U' or 'u', K specifies the number of
               super-diagonals of the matrix A.
               On entry with UPLO = 'L' or 'l', K specifies the number of
               sub-diagonals of the matrix A.
               K must satisfy  0 .le. K.

    A

              A is COMPLEX array, dimension ( LDA, N ).
               Before entry with UPLO = 'U' or 'u', the leading ( k + 1 )
               by n part of the array A must contain the upper triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row
               ( k + 1 ) of the array, the first super-diagonal starting at
               position 2 in row k, and so on. The top left k by k triangle
               of the array A is not referenced.
               The following program segment will transfer an upper
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = K + 1 - J
                        DO 10, I = MAX( 1, J - K ), J
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Before entry with UPLO = 'L' or 'l', the leading ( k + 1 )
               by n part of the array A must contain the lower triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row 1 of
               the array, the first sub-diagonal starting at position 1 in
               row 2, and so on. The bottom right k by k triangle of the
               array A is not referenced.
               The following program segment will transfer a lower
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = 1 - J
                        DO 10, I = J, MIN( N, J + K )
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Note that when DIAG = 'U' or 'u' the elements of the array A
               corresponding to the diagonal elements of the matrix are not
               referenced, but are assumed to be unity.

    LDA

              LDA is INTEGER
               On entry, LDA specifies the first dimension of A as declared
               in the calling (sub) program. LDA must be at least
               ( k + 1 ).

    X

              X is COMPLEX array, dimension at least
               ( 1 + ( n - 1 )*abs( INCX ) ).
               Before entry, the incremented array X must contain the n
               element vector x. On exit, X is overwritten with the
               transformed vector x.

    INCX

              INCX is INTEGER
               On entry, INCX specifies the increment for the elements of
               X. INCX must not be zero.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Further Details:

      Level 2 Blas routine.
      The vector and matrix arguments are not referenced when N = 0, or M = 0
      -- Written on 22-October-1986.
         Jack Dongarra, Argonne National Lab.
         Jeremy Du Croz, Nag Central Office.
         Sven Hammarling, Nag Central Office.
         Richard Hanson, Sandia National Labs.

Definition at line 185 of file ctbmv.f.

  subroutine dtbmv (character uplo, character trans, character diag, integer n, integer k, double precision, dimension(lda,*) a, integer lda, double precision, dimension(*) x, integer incx)

DTBMV

Purpose:

     DTBMV  performs one of the matrix-vector operations
        x := A*x,   or   x := A**T*x,
     where x is an n element vector and  A is an n by n unit, or non-unit,
     upper or lower triangular band matrix, with ( k + 1 ) diagonals.

Parameters
    UPLO

              UPLO is CHARACTER*1
               On entry, UPLO specifies whether the matrix is an upper or
               lower triangular matrix as follows:
                  UPLO = 'U' or 'u'   A is an upper triangular matrix.
                  UPLO = 'L' or 'l'   A is a lower triangular matrix.

    TRANS

              TRANS is CHARACTER*1
               On entry, TRANS specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'   x := A*x.
                  TRANS = 'T' or 't'   x := A**T*x.
                  TRANS = 'C' or 'c'   x := A**T*x.

    DIAG

              DIAG is CHARACTER*1
               On entry, DIAG specifies whether or not A is unit
               triangular as follows:
                  DIAG = 'U' or 'u'   A is assumed to be unit triangular.
                  DIAG = 'N' or 'n'   A is not assumed to be unit
                                      triangular.

    N

              N is INTEGER
               On entry, N specifies the order of the matrix A.
               N must be at least zero.

    K

              K is INTEGER
               On entry with UPLO = 'U' or 'u', K specifies the number of
               super-diagonals of the matrix A.
               On entry with UPLO = 'L' or 'l', K specifies the number of
               sub-diagonals of the matrix A.
               K must satisfy  0 .le. K.

    A

              A is DOUBLE PRECISION array, dimension ( LDA, N )
               Before entry with UPLO = 'U' or 'u', the leading ( k + 1 )
               by n part of the array A must contain the upper triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row
               ( k + 1 ) of the array, the first super-diagonal starting at
               position 2 in row k, and so on. The top left k by k triangle
               of the array A is not referenced.
               The following program segment will transfer an upper
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = K + 1 - J
                        DO 10, I = MAX( 1, J - K ), J
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Before entry with UPLO = 'L' or 'l', the leading ( k + 1 )
               by n part of the array A must contain the lower triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row 1 of
               the array, the first sub-diagonal starting at position 1 in
               row 2, and so on. The bottom right k by k triangle of the
               array A is not referenced.
               The following program segment will transfer a lower
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = 1 - J
                        DO 10, I = J, MIN( N, J + K )
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Note that when DIAG = 'U' or 'u' the elements of the array A
               corresponding to the diagonal elements of the matrix are not
               referenced, but are assumed to be unity.

    LDA

              LDA is INTEGER
               On entry, LDA specifies the first dimension of A as declared
               in the calling (sub) program. LDA must be at least
               ( k + 1 ).

    X

              X is DOUBLE PRECISION array, dimension at least
               ( 1 + ( n - 1 )*abs( INCX ) ).
               Before entry, the incremented array X must contain the n
               element vector x. On exit, X is overwritten with the
               transformed vector x.

    INCX

              INCX is INTEGER
               On entry, INCX specifies the increment for the elements of
               X. INCX must not be zero.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Further Details:

      Level 2 Blas routine.
      The vector and matrix arguments are not referenced when N = 0, or M = 0
      -- Written on 22-October-1986.
         Jack Dongarra, Argonne National Lab.
         Jeremy Du Croz, Nag Central Office.
         Sven Hammarling, Nag Central Office.
         Richard Hanson, Sandia National Labs.

Definition at line 185 of file dtbmv.f.

  subroutine stbmv (character uplo, character trans, character diag, integer n, integer k, real, dimension(lda,*) a, integer lda, real, dimension(*) x, integer incx)

STBMV

Purpose:

     STBMV  performs one of the matrix-vector operations
        x := A*x,   or   x := A**T*x,
     where x is an n element vector and  A is an n by n unit, or non-unit,
     upper or lower triangular band matrix, with ( k + 1 ) diagonals.

Parameters
    UPLO

              UPLO is CHARACTER*1
               On entry, UPLO specifies whether the matrix is an upper or
               lower triangular matrix as follows:
                  UPLO = 'U' or 'u'   A is an upper triangular matrix.
                  UPLO = 'L' or 'l'   A is a lower triangular matrix.

    TRANS

              TRANS is CHARACTER*1
               On entry, TRANS specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'   x := A*x.
                  TRANS = 'T' or 't'   x := A**T*x.
                  TRANS = 'C' or 'c'   x := A**T*x.

    DIAG

              DIAG is CHARACTER*1
               On entry, DIAG specifies whether or not A is unit
               triangular as follows:
                  DIAG = 'U' or 'u'   A is assumed to be unit triangular.
                  DIAG = 'N' or 'n'   A is not assumed to be unit
                                      triangular.

    N

              N is INTEGER
               On entry, N specifies the order of the matrix A.
               N must be at least zero.

    K

              K is INTEGER
               On entry with UPLO = 'U' or 'u', K specifies the number of
               super-diagonals of the matrix A.
               On entry with UPLO = 'L' or 'l', K specifies the number of
               sub-diagonals of the matrix A.
               K must satisfy  0 .le. K.

    A

              A is REAL array, dimension ( LDA, N )
               Before entry with UPLO = 'U' or 'u', the leading ( k + 1 )
               by n part of the array A must contain the upper triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row
               ( k + 1 ) of the array, the first super-diagonal starting at
               position 2 in row k, and so on. The top left k by k triangle
               of the array A is not referenced.
               The following program segment will transfer an upper
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = K + 1 - J
                        DO 10, I = MAX( 1, J - K ), J
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Before entry with UPLO = 'L' or 'l', the leading ( k + 1 )
               by n part of the array A must contain the lower triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row 1 of
               the array, the first sub-diagonal starting at position 1 in
               row 2, and so on. The bottom right k by k triangle of the
               array A is not referenced.
               The following program segment will transfer a lower
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = 1 - J
                        DO 10, I = J, MIN( N, J + K )
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Note that when DIAG = 'U' or 'u' the elements of the array A
               corresponding to the diagonal elements of the matrix are not
               referenced, but are assumed to be unity.

    LDA

              LDA is INTEGER
               On entry, LDA specifies the first dimension of A as declared
               in the calling (sub) program. LDA must be at least
               ( k + 1 ).

    X

              X is REAL array, dimension at least
               ( 1 + ( n - 1 )*abs( INCX ) ).
               Before entry, the incremented array X must contain the n
               element vector x. On exit, X is overwritten with the
               transformed vector x.

    INCX

              INCX is INTEGER
               On entry, INCX specifies the increment for the elements of
               X. INCX must not be zero.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Further Details:

      Level 2 Blas routine.
      The vector and matrix arguments are not referenced when N = 0, or M = 0
      -- Written on 22-October-1986.
         Jack Dongarra, Argonne National Lab.
         Jeremy Du Croz, Nag Central Office.
         Sven Hammarling, Nag Central Office.
         Richard Hanson, Sandia National Labs.

Definition at line 185 of file stbmv.f.

  subroutine ztbmv (character uplo, character trans, character diag, integer n, integer k, complex*16, dimension(lda,*) a, integer lda, complex*16, dimension(*) x, integer incx)

ZTBMV

Purpose:

     ZTBMV  performs one of the matrix-vector operations
        x := A*x,   or   x := A**T*x,   or   x := A**H*x,
     where x is an n element vector and  A is an n by n unit, or non-unit,
     upper or lower triangular band matrix, with ( k + 1 ) diagonals.

Parameters
    UPLO

              UPLO is CHARACTER*1
               On entry, UPLO specifies whether the matrix is an upper or
               lower triangular matrix as follows:
                  UPLO = 'U' or 'u'   A is an upper triangular matrix.
                  UPLO = 'L' or 'l'   A is a lower triangular matrix.

    TRANS

              TRANS is CHARACTER*1
               On entry, TRANS specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'   x := A*x.
                  TRANS = 'T' or 't'   x := A**T*x.
                  TRANS = 'C' or 'c'   x := A**H*x.

    DIAG

              DIAG is CHARACTER*1
               On entry, DIAG specifies whether or not A is unit
               triangular as follows:
                  DIAG = 'U' or 'u'   A is assumed to be unit triangular.
                  DIAG = 'N' or 'n'   A is not assumed to be unit
                                      triangular.

    N

              N is INTEGER
               On entry, N specifies the order of the matrix A.
               N must be at least zero.

    K

              K is INTEGER
               On entry with UPLO = 'U' or 'u', K specifies the number of
               super-diagonals of the matrix A.
               On entry with UPLO = 'L' or 'l', K specifies the number of
               sub-diagonals of the matrix A.
               K must satisfy  0 .le. K.

    A

              A is COMPLEX*16 array, dimension ( LDA, N ).
               Before entry with UPLO = 'U' or 'u', the leading ( k + 1 )
               by n part of the array A must contain the upper triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row
               ( k + 1 ) of the array, the first super-diagonal starting at
               position 2 in row k, and so on. The top left k by k triangle
               of the array A is not referenced.
               The following program segment will transfer an upper
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = K + 1 - J
                        DO 10, I = MAX( 1, J - K ), J
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Before entry with UPLO = 'L' or 'l', the leading ( k + 1 )
               by n part of the array A must contain the lower triangular
               band part of the matrix of coefficients, supplied column by
               column, with the leading diagonal of the matrix in row 1 of
               the array, the first sub-diagonal starting at position 1 in
               row 2, and so on. The bottom right k by k triangle of the
               array A is not referenced.
               The following program segment will transfer a lower
               triangular band matrix from conventional full matrix storage
               to band storage:
                     DO 20, J = 1, N
                        M = 1 - J
                        DO 10, I = J, MIN( N, J + K )
                           A( M + I, J ) = matrix( I, J )
                  10    CONTINUE
                  20 CONTINUE
               Note that when DIAG = 'U' or 'u' the elements of the array A
               corresponding to the diagonal elements of the matrix are not
               referenced, but are assumed to be unity.

    LDA

              LDA is INTEGER
               On entry, LDA specifies the first dimension of A as declared
               in the calling (sub) program. LDA must be at least
               ( k + 1 ).

    X

              X is COMPLEX*16 array, dimension at least
               ( 1 + ( n - 1 )*abs( INCX ) ).
               Before entry, the incremented array X must contain the n
               element vector x. On exit, X is overwritten with the
               transformed vector x.

    INCX

              INCX is INTEGER
               On entry, INCX specifies the increment for the elements of
               X. INCX must not be zero.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Further Details:

      Level 2 Blas routine.
      The vector and matrix arguments are not referenced when N = 0, or M = 0
      -- Written on 22-October-1986.
         Jack Dongarra, Argonne National Lab.
         Jeremy Du Croz, Nag Central Office.
         Sven Hammarling, Nag Central Office.
         Richard Hanson, Sandia National Labs.

Definition at line 185 of file ztbmv.f.

Author

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