# NAG FL Interfacex04daf (print_​matrix_​complex_​gen)

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## 1Purpose

x04daf is an easy-to-use routine to print a complex matrix stored in a two-dimensional array.

## 2Specification

Fortran Interface
 Subroutine x04daf ( diag, m, n, a, lda,
 Integer, Intent (In) :: m, n, lda Integer, Intent (Inout) :: ifail Complex (Kind=nag_wp), Intent (In) :: a(lda,*) Character (*), Intent (In) :: title Character (1), Intent (In) :: matrix, diag
#include <nag.h>
 void x04daf_ (const char *matrix, const char *diag, const Integer *m, const Integer *n, const Complex a[], const Integer *lda, const char *title, Integer *ifail, const Charlen length_matrix, const Charlen length_diag, const Charlen length_title)
The routine may be called by the names x04daf or nagf_file_print_matrix_complex_gen.

## 3Description

x04daf prints a complex matrix. It is an easy-to-use driver for x04dbf. The routine uses default values for the format in which numbers are printed, for labelling the rows and columns, and for output record length.
x04daf will choose a format code such that numbers will be printed with an $\mathrm{F}8.4$, an $\mathrm{F}11.4$ or a $1\mathrm{PE}13.4$ format. The $\mathrm{F}8.4$ code is chosen if the sizes of all the matrix elements to be printed lie between $0.001$ and $1.0$. The $\mathrm{F}11.4$ code is chosen if the sizes of all the matrix elements to be printed lie between $0.001$ and $9999.9999$. Otherwise the $1\mathrm{PE}13.4$ code is chosen. The chosen code is used to print each complex element of the matrix with the real part above the imaginary part.
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 x04abf.

None.

## 5Arguments

1: $\mathbf{matrix}$Character(1) Input
On entry: 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: $\mathbf{diag}$Character(1) Input
On entry: 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: $\mathbf{m}$Integer Input
4: $\mathbf{n}$Integer Input
On entry: the number of rows and columns of the matrix, respectively, to be printed.
If either m or n is less than $1$, x04daf will exit immediately after printing title; no row or column labels are printed.
5: $\mathbf{a}\left({\mathbf{lda}},*\right)$Complex (Kind=nag_wp) array Input
Note: the second dimension of the array a must be at least $\mathrm{max}\phantom{\rule{0.125em}{0ex}}\left(1,{\mathbf{n}}\right)$.
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.
6: $\mathbf{lda}$Integer Input
On entry: the first dimension of the array a as declared in the (sub)program from which x04daf is called.
Constraint: ${\mathbf{lda}}\ge \mathrm{max}\phantom{\rule{0.125em}{0ex}}\left(1,{\mathbf{m}}\right)$.
7: $\mathbf{title}$Character(*) Input
On entry: a title to be printed above the matrix.
If , 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.
8: $\mathbf{ifail}$Integer Input/Output
On entry: ifail must be set to $0$, $-1$ or $1$ to set behaviour on detection of an error; these values have no effect when no error is detected.
A value of $0$ causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of $-1$ means that an error message is printed while a value of $1$ means that it is not.
If halting is not appropriate, the value $-1$ or $1$ is recommended. If message printing is undesirable, then the value $1$ is recommended. Otherwise, the value $0$ is recommended. When the value $-\mathbf{1}$ or $\mathbf{1}$ is used it is essential to test the value of ifail on exit.
On exit: ${\mathbf{ifail}}={\mathbf{0}}$ unless the routine detects an error or a warning has been flagged (see Section 6).

## 6Error Indicators and Warnings

If on entry ${\mathbf{ifail}}=0$ or $-1$, explanatory error messages are output on the current error message unit (as defined by x04aaf).
Errors or warnings detected by the routine:
${\mathbf{ifail}}=1$
On entry, matrix is not valid: ${\mathbf{matrix}}=⟨\mathit{\text{value}}⟩$.
${\mathbf{ifail}}=2$
On entry, ${\mathbf{matrix}}=⟨\mathit{\text{value}}⟩$, but diag is not valid: ${\mathbf{diag}}=⟨\mathit{\text{value}}⟩$.
${\mathbf{ifail}}=3$
On entry, ${\mathbf{m}}=⟨\mathit{\text{value}}⟩$ and ${\mathbf{lda}}=⟨\mathit{\text{value}}⟩$.
Constraint: ${\mathbf{m}}\le {\mathbf{lda}}$.
${\mathbf{ifail}}=-99$
See Section 7 in the Introduction to the NAG Library FL Interface for further information.
${\mathbf{ifail}}=-399$
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library FL Interface for further information.
${\mathbf{ifail}}=-999$
Dynamic memory allocation failed.
See Section 9 in the Introduction to the NAG Library FL Interface for further information.

Not applicable.

## 8Parallelism and Performance

x04daf is not threaded in any implementation.

A call to x04daf is equivalent to a call to x04dbf with the following argument values:
• ${\mathbf{ncols}}=80$
• ${\mathbf{indent}}=0$
• ${\mathbf{labrow}}=\text{'I'}$
• ${\mathbf{labcol}}=\text{'I'}$
• ${\mathbf{usefrm}}=\text{'A'}$

## 10Example

This example program calls x04daf twice, first to print a $4×3$ rectangular matrix, and then to print a $4×4$ lower triangular matrix.

### 10.1Program Text

Program Text (x04dafe.f90)

None.

### 10.3Program Results

Program Results (x04dafe.r)