NX Nastran DMAP Programmer's Guide - Kxcad.net

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Introduction to DMAP
1.1 Introduction to DMAP
NX Nastran DMAP (Direct Matrix Abstraction Program) is a high-level language with
its own compiler and grammatical rules. This section provides a summary description
of the NX Nastran DMAP language, rules, and syntax.
A DMAP program consists of a series of functional blocks called “modules,” each of
which has a unique name and a specific function. Modules are executed sequentially;
branching and looping operations are performed by DMAP control statements.
Modules communicate through the NX Nastran Executive System (NES) via logical
collections of data called “data blocks” and “parameters.”
Data blocks come in two distinct forms: “matrices” that obey the rules of matrix
algebra, and “tables” that represent a convenient collection of data items. Data blocks
are given arbitrary names (mnemonic names are recommended) and have header and
trailer information defining their characteristics.
Parameters are scalar items used for specifying control, operation, or system
characteristics. Modules can use “input parameters,” “output parameters,” or both.
Input parameters affect the internal operation of the modules. Output parameters are
used to control DMAP logic and/or to pass scalar information to subsequent modules.
Data blocks and parameters can be written onto either scratch or permanent physical
files. When the normal NX Nastran execution completes, data blocks and parameters
written to scratch files are erased, and those written to the permanent physical file are
available for future use. The NDDL (NX Nastran Data Definition Language)
designates whether a data block is scratch or permanent. A detailed description of the
NDDL statements can be found in “NASTRAN Data Definition Language (NDDL)”
on page 739.
NX Nastran provides the user with a variety of prewritten solution sequences. These
solution sequences consist of a series of DMAP statements. You can use DMAP to
modify these prewritten solution sequences or to write your own solution sequences.
The compilation, linkage, and execution of a DMAP program is specified by executive
control statements in the input file. The creation of and access to databases is specified
by file management statements also contained in the input file. File management
statements are described in the “File Management Statements” in Chapter 2 of the
NX Nastran Quick Reference Guide.