NX Nastran DMAP Programmer's Guide - Kxcad.net

1.4 Data Blocks
Data Blocks
A data block is a table or matrix represented by a symbolic name. All data blocks are
comprised of records. Each record can contain a variable number of words.
The first record ("Record 0") is called the header record, of which the first two words
(when concatenated) form the name of the data block. The third and subsequent
words are not usually used.
The subsequent records are sometimes called "data records." For tables the data record
can contain a mixture of any type of data; i.e, real, integer, complex, character, etc. For
matrices the data record corresponds to the nonzero values in the column of the
matrix; e.g., record 3 corresponds to the nonzero values in column 3.
The last record is called the trailer record and contains summary information about
the table or matrix. More detailed descriptions of a data block’s records are appear in
“Data Blocks” on page 51.
Table Trailers
In tables, the trailer record contains six words. The contents vary among the tables
and are described in “Data Blocks” on page 51 at the end of the table’s description.
Table trailers are printed when DIAG 15 is specified in the Executive Control or
DIAGON(15) is specified in the DMAP sequence.
Matrix Trailers
In matrices the characteristics of a matrix are described in a twelve-word matrix
trailer. Matrix trailers are printed when DIAG 8 is present in the Executive Control
Section DIAGON(8) or is specified in the DMAP sequence. The contents of a matrix
trailer are as follows:
13