dlattb.f3

Usage

Functions/Subroutines

subroutine dlattb (imat, uplo, trans, diag, iseed, n, kd, ab, ldab, b, work, info)
DLATTB

Function/Subroutine Documentation

subroutine dlattb (integer imat, character uplo, character trans, character diag, integer, dimension( 4 ) iseed, integer n, integer kd, double precision, dimension( ldab, * ) ab, integer ldab, double precision, dimension( * ) b, double precision, dimension( * ) work, integer info)

DLATTB

Purpose:

!>
!> DLATTB generates a triangular test matrix in 2-dimensional storage.
!> IMAT and UPLO uniquely specify the properties of the test matrix,
!> which is returned in the array A.
!>

Parameters

IMAT

!>          IMAT is INTEGER
!>          An integer key describing which matrix to generate for this
!>          path.
!>

UPLO

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

TRANS

!>          TRANS is CHARACTER*1
!>          Specifies whether the matrix or its transpose will be used.
!>          = 'N':  No transpose
!>          = 'T':  Transpose
!>          = 'C':  Conjugate transpose (= transpose)
!>

DIAG

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

ISEED

!>          ISEED is INTEGER array, dimension (4)
!>          The seed vector for the random number generator (used in
!>          DLATMS).  Modified on exit.
!>

!>          N is INTEGER
!>          The order of the matrix to be generated.
!>

!>          KD is INTEGER
!>          The number of superdiagonals or subdiagonals of the banded
!>          triangular matrix A.  KD >= 0.
!>

!>          AB is DOUBLE PRECISION array, dimension (LDAB,N)
!>          The upper or lower triangular banded matrix A, stored in the
!>          first KD+1 rows of AB.  Let j be a column of A, 1<=j<=n.
!>          If UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j.
!>          If UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+kd).
!>

LDAB

!>          LDAB is INTEGER
!>          The leading dimension of the array AB.  LDAB >= KD+1.
!>

!>          B is DOUBLE PRECISION array, dimension (N)
!>

WORK

!>          WORK is DOUBLE PRECISION array, dimension (2*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 133 of file dlattb.f.