NX Nastran DMAP Programmer's Guide - Kxcad.net

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from the right, in each trailer word and beginning with trailer word 1. The table below
shows that correspondence between a trailer bit and its word and bit location in the
trailer.
Trailer Bit
For example, the GRID record in the GEOM1 data block is assigned to trailer bit 45
which corresponds to the 4th bit position, numbered from the right, in trailer word 3.
Based on the trailer bit, the following FORTRAN statements may be used to determine
the corresponding trailer word and bit position:
WORD = MOD(TBIT-1,96)/16 + 1
BIT = 16*(1+TBIT/97) - MOD(TBIT-1,16)
where TBIT = trailer bit from second word of header record
WORD = trailer word
BIT = trailer word bit position numbered from the right
and all variables are defined as integers.
Location in Trailer
Word Position
1 – 16 1 16 – 1
17 – 32 2 16 – 1
33 – 48 3 16 – 1
49 – 64 4 16 – 1
65 – 80 5 16 – 1
81 – 96 6 16 – 1
97 – 112 1 32 – 17
113 – 128 2 32 – 17
129 – 144 3 32 – 17
145 – 160 4 32 – 17
161 – 176 5 32 – 17