write_matrix

IMSL C Math Library

write_matrix

Prints a rectangular matrix (or vector) stored in contiguous memory locations.

Synopsis

#include <imsl.h>

void imsl_f_write_matrix (char *title, int nra, int nca, float a[], …, 0)

For int a[], use imsl_i_write_matrix.

For double a[], use imsl_d_write_matrix.

For f_complex a[], use imsl_c_write_matrix.

For d_complex a[], use imsl_z_write_matrix.

Required Arguments

char *title (Input)
The matrix title. Use \n within a title to create a new line. Long titles are automatically wrapped.

int nra (Input)
The number of rows in the matrix.

int nca (Input)
The number of columns in the matrix.

float a[] (Input)
Array of size nra × nca containing the matrix to be printed.

Synopsis with Optional Arguments

#include <imsl.h>

void imsl_f_write_matrix (char *title, int nra, int nca, float a[],

IMSL_TRANSPOSE,

IMSL_A_COL_DIM, int a_col_dim,

IMSL_PRINT_ALL,

IMSL_PRINT_LOWER,

IMSL_PRINT_UPPER,

IMSL_PRINT_LOWER_NO_DIAG,

IMSL_PRINT_UPPER_NO_DIAG,

IMSL_WRITE_FORMAT, char *fmt,

IMSL_ROW_LABELS, char *rlabel[],

IMSL_NO_ROW_LABELS,

IMSL_ROW_NUMBER,

IMSL_ROW_NUMBER_ZERO,

IMSL_COL_LABELS, char *clabel[],

IMSL_NO_COL_LABELS,

IMSL_COL_NUMBER,

IMSL_COL_NUMBER_ZERO,

IMSL_RETURN_STRING, char **string,

IMSL_WRITE_TO_CONSOLE,

Optional Arguments

IMSL_TRANSPOSE
Print aT.

IMSL_A_COL_DIM, int a_col_dim (Input)
The column dimension of a.
Default: a_col_dim = nca

IMSL_PRINT_ALL, or

IMSL_PRINT_LOWER, or

IMSL_PRINT_UPPER, or

IMSL_PRINT_LOWER_NO_DIAG, or

IMSL_PRINT_UPPER_NO_DIAG
Exactly one of these optional arguments can be specified in order to indicate that either a triangular part of the matrix or the entire matrix is to be printed. If omitted, the entire matrix is printed.


Keyword	Action
IMSL_PRINT_ALL	The entire matrix is printed (the default).
IMSL_PRINT_LOWER	The lower triangle of the matrix is printed, including the diagonal.
IMSL_PRINT_UPPER	The upper triangle of the matrix is printed, including the diagonal.
IMSL_PRINT_LOWER_NO_DIAG	The lower triangle of the matrix is printed, without the diagonal.
IMSL_PRINT_UPPER_NO_DIAG	The upper triangle of the matrix is printed, without the diagonal.

IMSL_WRITE_FORMAT, char *fmt (Input)
Character string containing a list of C conversion specifications (formats) to be used when printing the matrix. Any list of C conversion specifications suitable for the data type may be given. For example, fmt = "%10.3f" specifies the conversion character f for the entire matrix. (For the conversion character f, the matrix must be of type float, double, f_complex, or d_complex). Alternatively, fmt = "%10.3e%10.3e%10.3f%10.3f%10.3f" specifies the conversion character e for columns 1 and 2 and the conversion character f for columns 3, 4, and 5. (For complex matrices, two conversion specifications are required for each column of the matrix so the conversion character e is used in column 1. The conversion character f is used in column 2 and the real part of column 3.) If the end of fmt is encountered and if some columns of the matrix remain, format control continues with the first conversion specification in fmt.

Aside from restarting the format from the beginning, other exceptions to the usual C formatting rules are as follows:

Characters not associated with a conversion specification are not allowed. For example, in the format fmt = "1%d2%d", the characters 1 and 2 are not allowed and result in an error.

A conversion character d can be used for floating-point values (matrices of type float, double, f_complex, or d_complex). The integer part of the floating-point value is printed.

For printing numbers whose magnitudes are unknown, the conversion character g is useful; however, the decimal points will generally not be aligned when printing a column of numbers. The w (or W) conversion character is a special conversion character used by this function to select a conversion specification so that the decimal points will be aligned. The conversion specification ending with w is specified as "%n.dw". Here, n is the field width and d is the number of significant digits generally printed. Valid values for n are 3, 4, …, 40. Valid values for d are 1, 2, …, n-2. If fmt specifies one conversion specification ending with w, all elements of a are examined to determine one conversion specification for printing.

If fmt specifies more than one conversion specification, separate conversion specifications are generated for each conversion specification ending with w. Set fmt = "10.4w" if you want a single conversion specification selected automatically with field width 10 and with four significant digits.

IMSL_NO_ROW_LABELS, or

IMSL_ROW_NUMBER, or

IMSL_ROW_NUMBER_ZERO, or

IMSL_ROW_LABELS, char *rlabel[] (Input)
If IMSL_ROW_LABELS is specified, rlabel is a vector of length nra containing pointers to the character strings comprising the row labels. Here, nra is the number of rows in the printed matrix. Use \n within a label to create a new line. Long labels are automatically wrapped. If no row labels are desired, use the IMSL_NO_ROW_LABELS optional argument. If the numbers 1, 2, …, nra are desired, use the IMSL_ROW_NUMBER optional argument. If the numbers 1, 2, …, nra − 1 are desired, use the IMSL_ROW_NUMBER_ZERO optional argument. If none of these optional arguments is used, the numbers 1, 2, 3, …, nra are used for the row labels by default whenever nra > 1.
If nra = 1, the default is no row labels.

IMSL_NO_COL_LABELS, or

IMSL_COL_NUMBER, or

IMSL_COL_NUMBER_ZERO, or

IMSL_COL_LABELS, char *clabel[] (Input)
If IMSL_COL_LABELS is specified, clabel is a vector of length nca + 1 containing pointers to the character strings comprising the column headings. The heading for the row labels is clabel[0], and clabel[i], i = 1, …, nca, is the heading for the i-th column. Use \n within a label to create a new line. Long labels are automatically wrapped. If no column labels are desired, use the IMSL_NO_COL_LABELS optional argument. If the numbers 1, 2, …, nca, are desired, use the IMSL_COL_NUMBER optional argument. If the numbers 0, 1, …, nca − 1 are desired, use the IMSL_COL_NUMBER_ZERO optional argument. If none of these optional arguments is used, the numbers 1, 2, 3, …, nca are used for the column labels by default whenever nca > 1.
If nca = 1, the default is no column labels.

IMSL_RETURN_STRING, char **string (Output)
The address of a pointer to a NULL-terminated string containing the matrix to be printed. Lines are new-line separated and the last line does not have a trailing new-line character. Typically char *string is declared, and &string is used as the argument.

IMSL_WRITE_TO_CONSOLE
This matrix is printed to a console window. If a console has not been allocated, a default console (80 × 24, white on black, no scrollbars) is created.

Description

The function imsl_write_matrix prints a real rectangular matrix (stored in a) with optional row and column labels (specified by rlabel and clabel, respectively, regardless of whether a or aT is printed). An optional format, fmt, may be used to specify a conversion specification for each column of the matrix.

In addition, the write matrix functions can restrict printing to the elements of the upper or lower triangles of a matrix via the IMSL_TRIANGLE option. Generally, the IMSL_TRIANGLE option is used with symmetric matrices, but this is not required. Vectors can be printed by specifying a row or column dimension of 1.

Output is written to the file specified by the function imsl_output_file. The default output file is standard output (corresponding to the file pointer stdout).

A page width of 78 characters is used. Page width and page length can be reset by invoking function imsl_page.

Horizontal centering, the method for printing large matrices, paging, the method for printing NaN (Not a Number), and whether or not a title is printed on each page can be selected by invoking function imsl_write_options.

Examples

Example 1

This example is representative of the most common situation in which no optional arguments are given.

#include <imsl.h>

#define NRA 3

#define NCA 4

int main()

{

int i, j;

f_complex a[NRA][NCA];

for (i = 0; i < NRA; i++) {

for (j = 0; j < NCA; j++) {

a[i][j].re = (i+1+(j+1)*0.1);

a[i][j].im = -a[i][j].re+100;

}

/* Write matrix */

imsl_c_write_matrix ("matrix\na", NRA, NCA, (f_complex *)a, 0);

}

Output

matrix

1 2 3

1 ( 1.1, 98.9) ( 1.2, 98.8) ( 1.3, 98.7)

2 ( 2.1, 97.9) ( 2.2, 97.8) ( 2.3, 97.7)

3 ( 3.1, 96.9) ( 3.2, 96.8) ( 3.3, 96.7)

1 ( 1.4, 98.6)

2 ( 2.4, 97.6)

3 ( 3.4, 96.6)

Example 2

In this example, some of the optional arguments available in the write_matrix functions are demonstrated.

#include <imsl.h>

#define NRA 3

#define NCA 4

int main()

{

int i, j;

float a[NRA][NCA];

char *fmt = "%10.6W";

char *rlabel[] = {"row 1", "row 2", "row 3"};

char *clabel[] = { "", "col 1", "col 2", "col 3", "col 4"};

for (i = 0; i < NRA; i++) {

for (j = 0; j < NCA; j++) {

a[i][j] = (i+1+(j+1)*0.1);

}

/* Write matrix */

imsl_f_write_matrix ("matrix\na", NRA, NCA, (float *)a,

IMSL_WRITE_FORMAT, fmt,

IMSL_ROW_LABELS, rlabel,

IMSL_COL_LABELS, clabel,

IMSL_PRINT_UPPER_NO_DIAG,

0);

}

Output

matrix

col 2 col 3 col 4

row 1 1.2 1.3 1.4

row 2 2.3 2.4

row 3 3.4

Example 3

In this example, a row vector of length four is printed.

#include <imsl.h>

#define NRA 1

#define NCA 4

int main()

{

int i;

float a[NCA];

char *clabel[] = {"", "col 1", "col 2", "col 3", "col 4"};

for (i = 0; i < NCA; i++) {

a[i] = i + 1;

}

/* Write matrix */

imsl_f_write_matrix ("matrix\na", NRA, NCA, a,

IMSL_COL_LABELS, clabel,

0);

}

Output

matrix

col 1 col 2 col 3 col 4

1 2 3 4