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NAG Toolbox: nag_file_print_matrix_real_band (x04ce)

 Contents

    1  Purpose
    2  Syntax
    7  Accuracy
    9  Example

Purpose

nag_file_print_matrix_real_band (x04ce) is an easy-to-use function to print a double band matrix stored in a packed two-dimensional array.

Syntax

[ifail] = x04ce(m, n, kl, ku, a, title)
[ifail] = nag_file_print_matrix_real_band(m, n, kl, ku, a, title)

Description

nag_file_print_matrix_real_band (x04ce) prints a double band matrix stored in a packed two-dimensional array. It is an easy-to-use driver for nag_file_print_matrix_real_band_comp (x04cf). The function uses default values for the format in which numbers are printed, for labelling the rows and columns, and for output record length.
nag_file_print_matrix_real_band (x04ce) will choose a format code such that numbers will be printed with an F8.4, an F11.4 or a 1PE13.4 format . The F8.4 code is chosen if the sizes of all the matrix elements to be printed lie between 0.001 and 1.0. The F11.4 code is chosen if the sizes of all the matrix elements to be printed lie between 0.001 and 9999.9999. Otherwise the 1PE13.4 code is chosen.
The matrix is printed with integer row and column labels, and with a maximum record length of 80.
The matrix is output to the unit defined by nag_file_set_unit_advisory (x04ab).

References

None.

Parameters

Compulsory Input Parameters

1:     m int64int32nag_int scalar
2:     n int64int32nag_int scalar
The number of rows and columns of the band matrix, respectively, to be printed.
If either m or n is less than 1, nag_file_print_matrix_real_band (x04ce) will exit immediately after printing title; no row or column labels are printed.
3:     kl int64int32nag_int scalar
The number of subdiagonals of the band matrix A.
Constraint: kl0.
4:     ku int64int32nag_int scalar
The number of superdiagonals of the band matrix A.
Constraint: ku0.
5:     alda: – double array
The first dimension of the array a must be at least kl+ku+1.
The second dimension of the array a must be at least max1,minm+ku,n.
The band matrix to be printed.
The matrix is stored in rows 1 to kl+ku+1, more precisely, the element Aij must be stored in
aku+1+i-jj  for ​max1,j-kuiminm,j+kl. 
6:     title – string
A title to be printed above the matrix.
If title=' ', 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

None.

Output Parameters

1:     ifail int64int32nag_int scalar
ifail=0 unless the function detects an error (see Error Indicators and Warnings).

Error Indicators and Warnings

Errors or warnings detected by the function:
   ifail=1
On entry,kl<0.
   ifail=2
On entry,ku<0.
   ifail=3
On entry,lda<kl+ku+1.
   ifail=-99
An unexpected error has been triggered by this routine. Please contact NAG.
   ifail=-399
Your licence key may have expired or may not have been installed correctly.
   ifail=-999
Dynamic memory allocation failed.

Accuracy

Not applicable.

Further Comments

A call to nag_file_print_matrix_real_band (x04ce) is equivalent to a call to nag_file_print_matrix_real_band_comp (x04cf) with the following argument values:

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

Example

The example program calls nag_file_print_matrix_real_band (x04ce) to print a 5 by 5 band matrix with one subdiagonal and one superdiagonal.
function x04ce_example


fprintf('x04ce example results\n\n');

% Banded matrix (tridiagonal) A in banded storage format
m  = int64(5);
n  = m;
kl = int64(1);
ku = kl;
% diagonals are stored as rows and columns are preserved.
a  = [ 0, 12, 13, 14, 15;
      21, 22, 23, 24, 25;
      31, 32, 33, 34,  0];

mtitle = 'Band Matrix:';
[ifail] = x04ce(m, n, kl, ku, a, mtitle);


x04ce example results

 Band Matrix:
             1          2          3          4          5
 1     21.0000    12.0000
 2     31.0000    22.0000    13.0000
 3                32.0000    23.0000    14.0000
 4                           33.0000    24.0000    15.0000
 5                                      34.0000    25.0000

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Chapter Contents
Chapter Introduction
NAG Toolbox

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