F06 Chapter Contents
F06 Chapter Introduction
NAG Library Manual

# NAG Library Routine DocumentF06THF

Note:  before using this routine, please read the Users' Note for your implementation to check the interpretation of bold italicised terms and other implementation-dependent details.

## 1  Purpose

F06THF forms the complex $m$ by $n$ rectangular or trapezoidal matrix $A$ given by

## 2  Specification

 SUBROUTINE F06THF ( MATRIX, M, N, CON, DIAG, A, LDA)
 INTEGER M, N, LDA COMPLEX (KIND=nag_wp) CON, DIAG, A(LDA,*) CHARACTER(1) MATRIX

None.
None.

## 5  Parameters

1:     MATRIX – CHARACTER(1)Input
On entry: the matrix type.
${\mathbf{MATRIX}}=\text{'G'}$
General matrix.
${\mathbf{MATRIX}}=\text{'U'}$
Upper trapezoidal matrix (upper triangular if $m=n$).
${\mathbf{MATRIX}}=\text{'L'}$
Lower trapezoidal matrix (lower triangular if $m=n$).
Constraint: ${\mathbf{MATRIX}}=\text{'G'}$, $\text{'U'}$ or $\text{'L'}$.
2:     M – INTEGERInput
On entry: $m$, the number of rows of the matrix $A$.
Constraint: ${\mathbf{M}}\ge 0$.
3:     N – INTEGERInput
On entry: $n$, the number of columns of the matrix $A$.
Constraint: ${\mathbf{N}}\ge 0$.
4:     CON – COMPLEX (KIND=nag_wp)Input
On entry: the value to be assigned to the off-diagonal elements of $A$.
5:     DIAG – COMPLEX (KIND=nag_wp)Input
On entry: the value to be assigned to the diagonal elements of $A$.
6:     A(LDA,$*$) – COMPLEX (KIND=nag_wp) arrayOutput
Note: the second dimension of the array A must be at least ${\mathbf{N}}$.
On exit: the $m$ by $n$ general or trapezoidal matrix $A$.
• If ${\mathbf{MATRIX}}=\text{'U'}$, $A$ is upper trapezoidal and the elements of the array below the diagonal are not referenced.
• If ${\mathbf{MATRIX}}=\text{'L'}$, $A$ is lower trapezoidal and the elements of the array above the diagonal are not referenced.
7:     LDA – INTEGERInput
On entry: the first dimension of the array A as declared in the (sub)program from which F06THF is called.
Constraint: ${\mathbf{LDA}}\ge \mathrm{max}\phantom{\rule{0.125em}{0ex}}\left(1,{\mathbf{M}}\right)$.

None.

Not applicable.