# NAG FL Interfacex04ebf (print_​matrix_​integer_​comp)

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## 1Purpose

x04ebf prints an integer matrix stored in a two-dimensional array.

## 2Specification

Fortran Interface
 Subroutine x04ebf ( diag, m, n, a, lda, form,
 Integer, Intent (In) :: m, n, a(lda,*), lda, ncols, indent Integer, Intent (Inout) :: ifail Character (*), Intent (In) :: form, title, rlabs(*), clabs(*) Character (1), Intent (In) :: matrix, diag, labrow, labcol
#include <nag.h>
 void x04ebf_ (const char *matrix, const char *diag, const Integer *m, const Integer *n, const Integer a[], const Integer *lda, const char *form, const char *title, const char *labrow, const char rlabs[], const char *labcol, const char clabs[], const Integer *ncols, const Integer *indent, Integer *ifail, const Charlen length_matrix, const Charlen length_diag, const Charlen length_form, const Charlen length_title, const Charlen length_labrow, const Charlen length_rlabs, const Charlen length_labcol, const Charlen length_clabs)
The routine may be called by the names x04ebf or nagf_file_print_matrix_integer_comp.

## 3Description

x04ebf prints an integer matrix, or part of it, using a format specifier supplied by you. 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 $1$, x04ebf will exit immediately after printing title; no row or column labels are printed.
5: $\mathbf{a}\left({\mathbf{lda}},*\right)$Integer 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 x04ebf is called.
Constraint: ${\mathbf{lda}}\ge \mathrm{max}\phantom{\rule{0.125em}{0ex}}\left(1,{\mathbf{m}}\right)$.
7: $\mathbf{form}$Character(*) Input
On entry: a valid Fortran format code. This may be any format code allowed on the system, whether it is standard Fortran or not. form is used to print elements of the matrix $A$. It may or may not be enclosed in brackets. Examples of valid values for form are $\text{'}\mathrm{I6}\text{'}$, $\text{'}\mathrm{I4,2X}\text{'}$.
In addition, there is a special code which forces x04ebf to choose its own format code:
x04ebf will choose a format code such that numbers will be printed using the smallest edit descriptor that is large enough to hold all the numbers to be printed.
${\mathbf{form}}=\text{'MATLAB'}$ followed by any of the above, e.g., ${\mathbf{form}}=\text{'MATLABI6'}$, ${\mathbf{form}}=\text{'MATLAB*'}$
x04ebf will print the matrix such that it can be input into MATLAB. Elements of the matrix will be printed with format specified by the format code following ‘MATLAB’. title will be used as the name of the matrix.
Constraint: the character length of the format specifier in form must be $\text{}\le 80$.
8: $\mathbf{title}$Character(*) Input
On entry: a title to be printed above the matrix, or name of the matrix.
If , no title (and no blank line) will be printed.
If title contains more than ncols characters, the contents of title will be wrapped onto more than one line, with the break after ncols characters.
Any trailing blank characters in title are ignored.
If printing in MATLAB mode, title will be used as the name of the matrix.
9: $\mathbf{labrow}$Character(1) Input
On entry: indicates the type of labelling to be applied to the rows of the matrix, except in MATLAB mode where labrow is ignored.
${\mathbf{labrow}}=\text{'N'}$
Prints no row labels.
${\mathbf{labrow}}=\text{'I'}$
Prints integer row labels.
${\mathbf{labrow}}=\text{'C'}$
Prints character labels, which must be supplied in array rlabs.
Constraint: ${\mathbf{labrow}}=\text{'N'}$, $\text{'I'}$ or $\text{'C'}$.
10: $\mathbf{rlabs}\left(*\right)$Character(*) array Input
Note: the dimension of the array rlabs must be at least ${\mathbf{m}}$ if ${\mathbf{labrow}}=\text{'C'}$, and at least $1$ otherwise.
On entry: if ${\mathbf{labrow}}=\text{'C'}$, rlabs must contain labels for the rows of the matrix, except in MATLAB mode where rlabs is ignored.
Labels are right-justified when output, in a field which is as wide as necessary to hold the longest row label. Note that this field width is subtracted from the number of usable columns, ncols.
11: $\mathbf{labcol}$Character(1) Input
On entry: indicates the type of labelling to be applied to the columns of the matrix, except in MATLAB mode where labcol is ignored.
${\mathbf{labcol}}=\text{'N'}$
Prints no column labels.
${\mathbf{labcol}}=\text{'I'}$
Prints integer column labels.
${\mathbf{labcol}}=\text{'C'}$
Prints character labels, which must be supplied in array clabs.
Constraint: ${\mathbf{labcol}}=\text{'N'}$, $\text{'I'}$ or $\text{'C'}$.
12: $\mathbf{clabs}\left(*\right)$Character(*) array Input
Note: the dimension of the array clabs must be at least ${\mathbf{n}}$ if ${\mathbf{labcol}}=\text{'C'}$, and at least $1$ otherwise.
On entry: if ${\mathbf{labcol}}=\text{'C'}$, clabs must contain labels for the columns of the matrix, except in MATLAB mode where clabs is ignored.
Labels are right-justified when output. Any label that is too long for the column width, which is determined by form, is truncated.
13: $\mathbf{ncols}$Integer Input
On entry: the maximum output record length. If the number of columns of the matrix is too large to be accommodated in ncols characters, the matrix will be printed in parts, containing the largest possible number of matrix columns, and each part separated by a blank line.
ncols must be large enough to hold at least one column of the matrix using the format specifier in form. If a value less than $0$ or greater than $132$ is supplied for ncols, then the value $80$ is used instead.
14: $\mathbf{indent}$Integer Input
On entry: the number of columns by which the matrix (and any title and labels) should be indented. The effective value of ncols is reduced by indent columns. If a value less than $0$ or greater than ncols is supplied for indent, the value $0$ is used instead.
15: $\mathbf{ifail}$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: ${\mathbf{m}}\le {\mathbf{lda}}$.
${\mathbf{ifail}}=4$
The string $⟨\mathit{\text{value}}⟩$ has not been recognized as a valid format.
${\mathbf{ifail}}=5$
The string $⟨\mathit{\text{value}}⟩$ has not been recognized as a valid format.
${\mathbf{ifail}}=6$
On entry, either labrow or labcol is not valid ${\mathbf{labrow}}=⟨\mathit{\text{value}}⟩$, ${\mathbf{labcol}}=⟨\mathit{\text{value}}⟩$.
${\mathbf{ifail}}=7$
On entry, ${\mathbf{ncols}}-{\mathbf{indent}}$ is not wide enough to hold at least one matrix column: ${\mathbf{ncols}}=⟨\mathit{\text{value}}⟩$, ${\mathbf{indent}}=⟨\mathit{\text{value}}⟩$.
${\mathbf{ifail}}=-99$
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

x04ebf is not threaded in any implementation.

x04ebf may be used to print a vector, either as a row or as a column. The following code fragment illustrates possible calls.
```      Integer a(4)
Character*1 rlabs(1), clabs(1)
!     Print vector A as a column vector.
lda = 4
ifail = 0
Call x04ebf('G','X',4,1,a,lda,' ',' ','I',rlabs, &
'N',clabs,80,0,ifail)
!     Print vector A as a row vector.
lda = 1
ifail = 0
Call x04ebf('G','X',1,4,a,lda,' ',' ','N',rlabs, &
'I',clabs,80,0,ifail)```

## 10Example

This example calls x04ebf twice, first to print a $3×5$ rectangular matrix, and next to print a $5×5$ upper triangular matrix; various options for labelling and formatting are illustrated.

### 10.1Program Text

Program Text (x04ebfe.f90)

None.

### 10.3Program Results

Program Results (x04ebfe.r)