NAG Library Routine Document
X04DEF is an easy-to-use routine to print a
band matrix stored in a packed two-dimensional array.
||M, N, KL, KU, LDA, IFAIL
X04DEF prints a
band matrix stored in
It is an easy-to-use driver for X04DFF
. The routine uses default values for the format in which numbers are printed, for labelling the rows and columns, and for output record length.
X04DEF will choose a format code such that numbers will be printed with
an , an or a format.
code is chosen if the sizes of all the matrix elements to be printed lie between and . The
code is chosen if the sizes of all the matrix elements to be printed lie between and . Otherwise the
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 .
The matrix is output to the unit defined by X04ABF
- 1: M – INTEGERInput
- 2: N – INTEGERInput
: the number of rows and columns of the band matrix, respectively, to be printed.
If either M
is less than
, X04DEF will exit immediately after printing TITLE
; no row or column labels are printed.
- 3: KL – INTEGERInput
On entry: the number of subdiagonals of the band matrix .
- 4: KU – INTEGERInput
On entry: the number of superdiagonals of the band matrix .
- 5: A(LDA,) – COMPLEX (KIND=nag_wp) arrayInput
the second dimension of the array A
must be at least
: the band matrix to be printed.
The matrix is stored in rows
, more precisely, the element
must be stored in
- 6: LDA – INTEGERInput
: the first dimension of the array A
as declared in the (sub)program from which X04DEF is called.
- 7: TITLE – CHARACTER(*)Input
: a title to be printed above the matrix.
If , no title (and no blank line) will be printed.
contains more than
characters, the contents of TITLE
will be wrapped onto more than one line, with the break after
Any trailing blank characters in TITLE
- 8: IFAIL – INTEGERInput/Output
must be set to
. If you are unfamiliar with this parameter you should refer to Section 3.3
in the Essential Introduction for details.
For environments where it might be inappropriate to halt program execution when an error is detected, the value
is recommended. If the output of error messages is undesirable, then the value
is recommended. Otherwise, if you are not familiar with this parameter, the recommended value is
. When the value is used it is essential to test the value of IFAIL on exit.
unless the routine detects an error or a warning has been flagged (see Section 6
6 Error Indicators and Warnings
If on entry
, explanatory error messages are output on the current error message unit (as defined by X04AAF
Errors or warnings detected by the routine:
A call to X04DEF is equivalent to a call to X04DFF
with the following argument values:
NCOLS = 80
INDENT = 0
LABROW = 'I'
LABCOL = 'I'
FORM = ' '
USEFRM = 'A'
This example program calls X04DEF to print a by band matrix with one sub-diagonal and one super-diagonal.
9.1 Program Text
Program Text (x04defe.f90)
9.2 Program Data
9.3 Program Results
Program Results (x04defe.r)