mat_mul matA matBMAT_MUL(nged)
NAME
mat_mul - multiply two 4x4 matrices
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SYNOPSIS
DESCRIPTION
The mat_mul command multiplies two 4x4 homogeneous transformation matrices together, computing result = matA * matB. Both matA and matB must be provided as 16-element space-separated floating-point strings (as produced by bn_encode_mat). The result is returned in the same 16-element encoded format.
The operation is the standard 4x4 matrix product; it is the GED wrapper for bn_mat_mul. Note that matrix multiplication is not commutative — the order of operands matters.
EXAMPLES
Example 1. Multiply two identity matrices
mged> mat_mul "1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1" "1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1"
Returns the identity matrix 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1, since the product of two identity matrices is the identity.
Example 2. Chain two rotation matrices
mged> set m1 [mat_ae 45 0] mged> set m2 [mat_ae 0 30] mged> mat_mul $m1 $m2
Composes the azimuth rotation matrix $m1 with the elevation rotation matrix $m2, returning their combined transformation.
AUTHOR
BRL-CAD Team
BUG REPORTS
Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org