# dlattb.f - Man Page

TESTING/LIN/dlattb.f

## Synopsis

### 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*N is INTEGER The order of the matrix to be generated.

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

*AB*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*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**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

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

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK