void	x04cec (Nag_OrderType order, Integer m, Integer n, Integer kl, Integer ku, const double a[], Integer pda, const char title, const char outfile, NagError *fail)

The function may be called by the names: x04cec, nag_file_print_matrix_real_band or nag_band_real_mat_print.

3 Description

x04cec prints a double band matrix stored in packed form. It is an easy-to-use driver for x04cfc. The function uses default values for the format in which numbers are printed, for labelling the rows and columns, and for output record length.

x04cec will choose a format code such that numbers will be printed with a

% 8.4 f

, a

% 11.4 f

or a

% 13.4 e

format. The

% 8.4 f

code is chosen if the sizes of all the matrix elements to be printed lie between

0.001

and

1.0

. The

% 11.4 f

code is chosen if the sizes of all the matrix elements to be printed lie between

0.001

and

9999.9999

. Otherwise the

% 13.4 e

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 file specified by outfile or, by default, to standard output.

4 References

None.

5 Arguments

1: $order$ – Nag_OrderType Input

On entry: the order argument specifies the two-dimensional storage scheme being used, i.e., row-major ordering or column-major ordering. C language defined storage is specified by

order = Nag_RowMajor

. See Section 3.1.3 in the Introduction to the NAG Library CL Interface for a more detailed explanation of the use of this argument.

Constraint:

order = Nag_RowMajor

Nag_ColMajor

2: $m$ – Integer Input

3: $n$ – Integer Input

On entry: the number of rows and columns of the band matrix, respectively, to be printed.

If either m or n is less than

1

, x04cec will exit immediately after printing title; no row or column labels are printed.

4: $kl$ – Integer Input

On entry: the number of subdiagonals of the band matrix

A

Constraint:

kl \geq 0

5: $ku$ – Integer Input

On entry: the number of superdiagonals of the band matrix

A

Constraint:

ku \geq 0

6: $a [\dim]$ – const double Input

Note: the dimension, dim, of the array a must be at least

$\max (1, pda \times n)$ when $order = Nag_ColMajor$ ;
$\max (1, m \times pda)$ when $order = Nag_RowMajor$ .

On entry: the band matrix to be printed.

This is stored as a notional two-dimensional array with row elements or column elements stored contiguously. The storage of elements

A_{i j}

, for row

i = 1, \dots, m

and column

j = \max (1, i - k_{l}), \dots, \min (n, i + k_{u})

, depends on the order argument as follows:

if $order = Nag_ColMajor$ , $A_{i j}$ is stored as $a [(j - 1) \times pda + ku + i - j]$ ;
if $order = Nag_RowMajor$ , $A_{i j}$ is stored as $a [(i - 1) \times pda + kl + j - i]$ .

7: $pda$ – Integer Input

On entry: the stride separating row or column elements (depending on the value of order) of the matrix

A

in the array a.

Constraint:

pda \geq kl + ku + 1

8: $title$ – const char * Input

On entry: a title to be printed above the matrix.

title = NULL

, 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.

9: $outfile$ – const char * Input

On entry: the name of a file to which output will be directed. If outfile is NULL the output will be directed to standard output.

10: $fail$ – NagError * Input/Output

The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).

6 Error Indicators and Warnings

NE_ALLOC_FAIL: Memory allocation failed.
NE_BAD_PARAM: On entry, argument $⟨ value ⟩$ had an illegal value.
NE_INTERNAL_ERROR: An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.
NE_NOT_APPEND_FILE: Cannot open file $⟨ value ⟩$ for appending.
NE_NOT_CLOSE_FILE: Cannot close file $⟨ value ⟩$ .
NE_NOT_WRITE_FILE: Cannot open file $⟨ value ⟩$ for writing.