NAG Library Function Document

nag_gen_real_mat_print (x04cac)

1

Purpose

2

Specification

3

Description

4

References

5

Arguments

1:    $\mathbf{order}$ – Nag_OrderTypeInput

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 $\mathbf{order}=\mathrm{Nag\_RowMajor}$. See Section 3.3.1.3 in How to Use the NAG Library and its Documentation for a more detailed explanation of the use of this argument.

Constraint: $\mathbf{order}=\mathrm{Nag\_RowMajor}$ or $\mathrm{Nag\_ColMajor}$.

2:    $\mathbf{matrix}$ – Nag_MatrixTypeInput

On entry: indicates the part of the matrix to be printed.

$\mathbf{matrix}=\mathrm{Nag\_GeneralMatrix}$

The whole of the rectangular matrix.

$\mathbf{matrix}=\mathrm{Nag\_LowerMatrix}$

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

$\mathbf{matrix}=\mathrm{Nag\_UpperMatrix}$

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

Constraint: $\mathbf{matrix}=\mathrm{Nag\_GeneralMatrix}$, $\mathrm{Nag\_LowerMatrix}$ or $\mathrm{Nag\_UpperMatrix}$.

3:    $\mathbf{diag}$ – Nag_DiagTypeInput

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

$\mathbf{diag}=\mathrm{Nag\_NonRefDiag}$

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

$\mathbf{diag}=\mathrm{Nag\_UnitDiag}$

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

$\mathbf{diag}=\mathrm{Nag\_NonUnitDiag}$

The diagonal elements of the matrix are referenced and printed.

If $\mathbf{matrix}=\mathrm{Nag\_GeneralMatrix}$, then diag must be set to $\mathrm{Nag\_NonUnitDiag}$.

Constraints:

• if $\mathbf{matrix}\ne \mathrm{Nag\_GeneralMatrix}$, $\mathbf{diag}=\mathrm{Nag\_NonRefDiag}$, $\mathrm{Nag\_UnitDiag}$ or $\mathrm{Nag\_NonUnitDiag}$;
• if $\mathbf{matrix}=\mathrm{Nag\_GeneralMatrix}$, $\mathbf{diag}=\mathrm{Nag\_NonUnitDiag}$.

4:    $\mathbf{m}$ – IntegerInput

5:    $\mathbf{n}$ – IntegerInput

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

If either m or n is less than $1$, nag_gen_real_mat_print (x04cac) will exit immediately after printing title; no row or column labels are printed.

6:    $\mathbf{a}\left[\mathit{dim}\right]$ – const doubleInput

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

• $\max \left(1,\mathbf{pda}\times \mathbf{n}\right)$ when $\mathbf{order}=\mathrm{Nag\_ColMajor}$;
• $\max \left(1,\mathbf{m}\times \mathbf{pda}\right)$ when $\mathbf{order}=\mathrm{Nag\_RowMajor}$.

The $\left(i,j\right)$th element of the matrix $A$ is stored in

• $\mathbf{a}\left[\left(j-1\right)\times \mathbf{pda}+i-1\right]$ when $\mathbf{order}=\mathrm{Nag\_ColMajor}$;
• $\mathbf{a}\left[\left(i-1\right)\times \mathbf{pda}+j-1\right]$ when $\mathbf{order}=\mathrm{Nag\_RowMajor}$.

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

7:    $\mathbf{pda}$ – IntegerInput

On entry: the stride separating row or column elements (depending on the value of order) in the array a.

Constraints:

• if $\mathbf{order}=\mathrm{Nag\_ColMajor}$, $\mathbf{pda}\ge \max \left(1,\mathbf{m}\right)$;
• if $\mathbf{order}=\mathrm{Nag\_RowMajor}$, $\mathbf{pda}\ge \max \left(1,\mathbf{n}\right)$.

8:    $\mathbf{title}$ – const char *Input

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

If $\mathbf{title}=\mathbf{NULL}$, 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:    $\mathbf{outfile}$ – 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:  $\mathbf{fail}$ – NagError *Input/Output

The NAG error argument (see Section 3.7 in How to Use the NAG Library and its Documentation).

6

Error Indicators and Warnings

NE_ALLOC_FAIL

Memory allocation failed.

NE_BAD_PARAM

On entry, argument $〈\mathit{\text{value}}〉$ 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 $〈\mathit{\text{value}}〉$ for appending.

NE_NOT_CLOSE_FILE

Cannot close file $〈\mathit{\text{value}}〉$.

NE_NOT_WRITE_FILE

Cannot open file $〈\mathit{\text{value}}〉$ for writing.

7

Accuracy

8

Parallelism and Performance

9

Further Comments

ncols = 80
indent = 0
labrow = Nag_IntegerLabels
labcol = Nag_IntegerLabels
form = 0

10

Example