void	x04ccc (Nag_OrderType order, Nag_UploType uplo, Nag_DiagType diag, Integer n, const double a[], const char title, const char outfile, NagError *fail)

The function may be called by the names: x04ccc, nag_file_print_matrix_real_packed or nag_pack_real_mat_print.

3 Description

x04ccc prints a double triangular matrix stored in packed form. It is an easy-to-use driver for x04cdc. The function uses default values for the format in which numbers are printed, for labelling the rows and columns, and for output record length.

x04ccc 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: $uplo$ – Nag_UploType Input

On entry: indicates the type of the matrix to be printed

$uplo = Nag_Lower$: The matrix is lower triangular
$uplo = Nag_Upper$: The matrix is upper triangular

Constraint:

uplo = Nag_Lower

Nag_Upper

3: $diag$ – Nag_DiagType Input

On entry: indicates whether the diagonal elements of the matrix are to be printed.

$diag = Nag_NonRefDiag$: The diagonal elements of the matrix are not referenced and not printed.
$diag = Nag_UnitDiag$: The diagonal elements of the matrix are not referenced, but are assumed all to be unity, and are printed as such.
$diag = Nag_NonUnitDiag$: The diagonal elements of the matrix are referenced and printed.

Constraint:

diag = Nag_NonRefDiag

Nag_UnitDiag

Nag_NonUnitDiag

4: $n$ – Integer Input

On entry: the order of the matrix to be printed.

If n is less than

1

, x04ccc will exit immediately after printing title; no row or column labels are printed.

5: $a [\dim]$ – const double Input

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

\max (1, n \times (n + 1) / 2)

On entry: the matrix to be printed. Note that a must have space for the diagonal elements of the matrix, even if these are not stored.

The storage of elements

A_{i j}

depends on the order and uplo arguments as follows:

if $order = Nag_ColMajor$ and $uplo = Nag_Upper$ ,: $A_{i j}$ is stored in $a [(j - 1) \times j / 2 + i - 1]$ , for $i \leq j$ ;
if $order = Nag_ColMajor$ and $uplo = Nag_Lower$ ,: $A_{i j}$ is stored in $a [(2 n - j) \times (j - 1) / 2 + i - 1]$ , for $i \geq j$ ;
if $order = Nag_RowMajor$ and $uplo = Nag_Upper$ ,: $A_{i j}$ is stored in $a [(2 n - i) \times (i - 1) / 2 + j - 1]$ , for $i \leq j$ ;
if $order = Nag_RowMajor$ and $uplo = Nag_Lower$ ,: $A_{i j}$ is stored in $a [(i - 1) \times i / 2 + j - 1]$ , for $i \geq j$ .

diag = Nag_UnitDiag

, the diagonal elements of

A

are assumed to be

1

, and are not referenced; the same storage scheme is used whether

diag = Nag_NonUnitDiag

diag = Nag_UnitDiag

6: $title$ – 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.

7: $outfile$ – 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.

8: $fail$ – 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.