Argument Descriptions

The style of the argument descriptions is illustrated by the following example from LA_GESV:

A

(input/output) REAL or COMPLEX square array, shape (:,:).
On entry, the matrix $A$.
On exit, the factors $L$ and $U$ from the factorization $A=P L U$; the unit diagonal elements of $L$ are not stored.

B

(input/output) REAL or COMPLEX array, shape (:,:) with $size({\bf B},1)$ = $size({\bf A},1)$ or shape $(:)$ with $size({\bf B})=size({\bf A},1)$.
On entry, the matrix $B$.
On exit, the solution matrix $X$.

IPIV

Optional (output) INTEGER array, shape $(:)$ with $size({\bf IPIV})=size({\bf A},1)$.
The pivot indices that define the permutation matrix $P$; row $i$ of the matrix was interchanged with row ${\bf IPIV}_i\:$.

INFO

Optional (output) INTEGER


If ${\bf INFO}$ is not present and an error occurs, then the program is terminated with an error message.

The description of each argument gives:

• a classification of the argument as (input), (input/output), (output), (input or output)^3.1;
  
• the type of the argument;
  
• (for an array) its shape;
  
• the use of the argument on entry and/or on exit;
  
• (for a scalar input argument) any constraints that the supplied values must satisfy;
  
• (for optional input arguments) a default value.