In computer vision, the rotation of a point by &theta around the x axis is accomplished by multiplying by the matrix:[ D. H. Ballard and C. M. Brown, Computer Vision, Prentice-Hall, 1982, p. 477.]

lccr 1 0 0 0
0 cos &theta - sin &theta 0
0 sin &theta cos &theta 0
0 0 0 1

Many of the coefficients in this matrix are the special values 0, 1, or -1. In order to perform this operation with a standard matrix multiply subroutine, it would be necessary to:

• Create a matrix containing the 16 values.

• Call the subroutine to multiply by this matrix.

Many of the cycles consumed in the matrix multiply would be wasted because they would be trivial computations ( e.g., multiplying by 1 or adding 0).

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