write_options


option for Setting	option for Retrieving	Attribute Description
IMSL_SET_DEFAULTS		Use the default settings for all parameters
IMSL_SET_CENTERING	IMSL_GET_CENTERING	Horizontal centering
IMSL_SET_ROW_WRAP	IMSL_GET_ROW_WRAP	Row wrapping
IMSL_SET_PAGING	IMSL_GET_PAGING	Paging
IMSL_SET_NAN_CHAR	IMSL_GET_NAN_CHAR	Method for printing NaN (not a number)
IMSL_SET_TITLE_PAGE	IMSL_GET_TITLE_PAGE	Whether or not titles appear on each page
IMSL_SET_FORMAT	IMSL_GET_FORMAT	Default format for real and complex numbers

The function imsl_write_options allows the user to set or retrieve an option for printing a matrix. Options controlled by imsl_write_options are horizontal centering, method for printing large matrices, paging, method for printing in NaN (not a number), method for printing titles, and the default format for real and complex numbers. (NaN can be retrieved by functions imsl_f_machine and imsl_d_machine. For more information, see the description for imsl_f_machine.


Option	Value	Meaning
CENTERING	0 1	Matrix is left justified. Matrix is centered.
ROW_WRAP	0 m	A complete row is printed before the next row is printed. Wrapping is used if necessary. Here m is a positive integer. Let n1 be the maximum number of columns that fit across the page, as determined by the widths in the conversion specifications starting with column 1. First, columns 1 through n1 are printed for rows 1 through m. Let n2 be the maximum number of columns that fit across the page, starting with column n1 + 1. Second, columns n1+1 through n1 + n2 are printed for rows 1 through m. This continues until the last columns are printed for rows 1 through m. Printing continues in this fashion for the next m rows, etc.
PAGING	-2 -1 0 k	No paging occurs. Paging is on. Every invocation of a imsl_f_write_matrix function begins on a new page, and paging occurs within each invocation as is needed. Paging is on. The first invocation of a imsl_f_write_matrix function begins on a new page, and subsequent paging occurs as is needed. Paging occurs in the second and all subsequent calls to a imsl_f_write_matrix function only as needed. Turn paging on and set the number of lines printed on the current page to k lines. If k is greater than or equal to the page length, then the first invocation of a imsl_f_write_matrix function begins on a new page. In any case, subsequent paging occurs as is needed.
NAN_CHAR	0 1	. . . . . . . . . . is printed for NaN. A blank field is printed for NaN.
TITLE_PAGE	0 1	Title appears only on first page. Title appears on the first page and all continuation pages.
FORMAT	0 1 2	Format is "%10.4x". Format is "%12.6w". Format is "%22.5e".

The w conversion character used by the FORMAT option is a special conversion character that can be used to automatically select a pretty C conversion specification ending in either e, f, or d. 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.

The function imsl_write_options can be invoked repeatedly before using a write_matrix function to print a matrix. The matrix printing functions retrieve the values set by imsl_write_options to determine the printing options. It is not necessary to call imsl_write_options if a default value of a printing option is desired. The defaults are as follows:


Option	Default Value	Description
CENTERING	0	Left justified
ROW_WRAP	1000	Lines before wrapping
PAGING	-2	No paging
NAN_CHAR	0	. . . . . . . . . . . . . .
TITLE_PAGE	0	Title appears only on the first page
FORMAT	0	%10.4w

The following example illustrates the effect of imsl_write_options when printing a 3 × 4 real matrix A with IMSL function imsl_f_write_matrix, where aij = i + j∕10. The first call to imsl_write_options sets horizontal centering so that the matrix is printed centered horizontally on the page. In the next invocation of imsl_f_write_matrix, the left-justification option has been set via function imsl_write_options, so the matrix is left justified when printed.