NAG Toolbox: nag_file_print_matrix_real_gen (x04ca)

Purpose

Syntax

Description

References

Parameters

Compulsory Input Parameters

1:     $\mathrm{matrix}$ – string (length ≥ 1)

Indicates the part of the matrix to be printed.

$\mathbf{matrix}=\text{'G'}$

The whole of the rectangular matrix.

$\mathbf{matrix}=\text{'L'}$

The lower triangle of the matrix, or the lower trapezium if the matrix has more rows than columns.

$\mathbf{matrix}=\text{'U'}$

The upper triangle of the matrix, or the upper trapezium if the matrix has more columns than rows.

Constraint: $\mathbf{matrix}=\text{'G'}$, $\text{'L'}$ or $\text{'U'}$.

2:     $\mathrm{diag}$ – string (length ≥ 1)

Unless $\mathbf{matrix}=\text{'G'}$, diag must specify whether the diagonal elements of the matrix are to be printed.

$\mathbf{diag}=\text{'B'}$

The diagonal elements of the matrix are not referenced and not printed.

$\mathbf{diag}=\text{'U'}$

The diagonal elements of the matrix are not referenced, but are assumed all to be unity, and are printed as such.

$\mathbf{diag}=\text{'N'}$

The diagonal elements of the matrix are referenced and printed.

If $\mathbf{matrix}=\text{'G'}$, then diag need not be set.

Constraint: if $\mathbf{matrix}\ne \text{'G'}$, $\mathbf{diag}=\text{'B'}$, $\text{'U'}$ or $\text{'N'}$.

3:     $\mathrm{a}\left(\mathit{lda},:\right)$ – double array

The first dimension of the array a must be at least $\max \left(1,\mathbf{m}\right)$.

The second dimension of the array a must be at least $\max \left(1,\mathbf{n}\right)$.

The matrix to be printed. Only the elements that will be referred to, as specified by arguments matrix and diag, need be set.

4:     $\mathrm{title}$ – string

A title to be printed above the matrix.

If $\mathbf{title}=\text{' '}$, no title (and no blank line) will be printed.

If title contains more than $80$ characters, the contents of title will be wrapped onto more than one line, with the break after $80$ characters.

Any trailing blank characters in title are ignored.

Optional Input Parameters

1:     $\mathrm{m}$ – int64int32nag_int scalar

2:     $\mathrm{n}$ – int64int32nag_int scalar

Default: the first dimension of the array a and the second dimension of the array a.

The number of rows and columns of the matrix, respectively, to be printed.

If either m or n is less than $1$, nag_file_print_matrix_real_gen (x04ca) will exit immediately after printing title; no row or column labels are printed.

Output Parameters

1:     $\mathrm{ifail}$ – int64int32nag_int scalar

$\mathbf{ifail}=\mathbf{0}$ unless the function detects an error (see Error Indicators and Warnings).

Error Indicators and Warnings

   $\mathbf{ifail}=1$

On entry,

$\mathbf{matrix}\ne \text{'G'}$, $\text{'L'}$ or $\text{'U'}$.

   $\mathbf{ifail}=2$

On entry,

$\mathbf{matrix}=\text{'L'}$ or $\text{'U'}$, but $\mathbf{diag}\ne \text{'N'}$, $\text{'U'}$ or $\text{'B'}$.

   $\mathbf{ifail}=3$

On entry,

$\mathit{lda}<\mathbf{m}$.

   $\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

   $\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

   $\mathbf{ifail}=-999$

Dynamic memory allocation failed.

Accuracy

Further Comments

ncols = 80
indent = 0
labrow = 'I'
labcol = 'I'
form = ' '

Example

Open in the MATLAB editor: x04ca_example

function x04ca_example


fprintf('x04ca example results\n\n');

nmax = 5;
a = zeros(nmax,nmax);

for i = 1:nmax
  a(i,:) = [1:nmax] + 10*i;
end

% First matrix : 3x5 general matrix 
mtitle = 'Example 1:';
matrix = 'General';
diag   = ' ';

[ifail] = x04ca( ...
                 matrix, diag, a(1:3,:), mtitle);

fprintf('\n');
% Second matrix : 5x5 non-unit lower triangular 
mtitle = 'Example 2:';
matrix = 'Lower';
diag   = 'Non-unit';

[ifail] = x04ca( ...
                 matrix, diag, a, mtitle);

x04ca example results

 Example 1:
             1          2          3          4          5
 1     11.0000    12.0000    13.0000    14.0000    15.0000
 2     21.0000    22.0000    23.0000    24.0000    25.0000
 3     31.0000    32.0000    33.0000    34.0000    35.0000

 Example 2:
             1          2          3          4          5
 1     11.0000
 2     21.0000    22.0000
 3     31.0000    32.0000    33.0000
 4     41.0000    42.0000    43.0000    44.0000
 5     51.0000    52.0000    53.0000    54.0000    55.0000