The routine may be called by the names x04ccf or nagf_file_print_matrix_real_packed.
x04ccf prints a real triangular matrix stored in packed form. It is an easy-to-use driver for x04cdf. The routine uses default values for the format in which numbers are printed, for labelling the rows and columns, and for output record length.
The matrix must be packed by column.
x04ccf will choose a format code such that numbers will be printed with
an , an or a
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 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: – Character(1)Input
On entry: indicates the type of the matrix to be printed
The matrix is lower triangular. In this case, the packed array a holds the matrix elements in the following order: , etc.
The matrix is upper triangular. In this case, the packed array a holds the matrix elements in the following order: , etc.
2: – Character(1)Input
On entry: indicates whether the diagonal elements of the matrix are to be printed.
The diagonal elements of the matrix are not referenced and not printed.
The diagonal elements of the matrix are not referenced, but are assumed all to be unity, and are printed as such.
The diagonal elements of the matrix are referenced and printed.
, or .
3: – IntegerInput
On entry: the order of the matrix to be printed.
If n is less than , x04ccf will exit immediately after printing title; no row or column labels are printed.
4: – Real (Kind=nag_wp) arrayInput
Note: the dimension of the array a
must be at least
On entry: the matrix to be printed. Note that a must have space for the diagonal elements of the matrix, even if these are not stored.
if , the upper triangle of must be stored with element in for ;
if , the lower triangle of must be stored with element in for .
If , the diagonal elements of are assumed to be , and are not referenced; the same storage scheme is used whether or ‘U’.
5: – 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 characters, the contents of title will be wrapped onto more than one line, with the break after characters.
Any trailing blank characters in title are ignored.
6: – IntegerInput/Output
On entry: ifail must be set to , or to set behaviour on detection of an error; these values have no effect when no error is detected.
A value of causes the printing of an error message and program execution will be halted; otherwise program execution continues. A value of means that an error message is printed while a value of means that it is not.
If halting is not appropriate, the value or is recommended. If message printing is undesirable, then the value is recommended. Otherwise, the value is recommended. When the value or is used it is essential to test the value of ifail on exit.
On exit: unless the routine detects an error or a warning has been flagged (see Section 6).
6Error Indicators and Warnings
If on entry or , explanatory error messages are output on the current error message unit (as defined by x04aaf).