The SPRSAX function takes a row-indexed sparse array created by the SPRSIN function and multiplies it by an n-element vector to its right.
SPRSAX is based on the routine
sprsax described in section 2.7 of Numerical Recipes in C: The Art of Scientific Computing (Second Edition), published by Cambridge University Press, and is used by permission.
Result = SPRSAX( A, X [, /DOUBLE] )
Returns a n-element vector.
A row-indexed sparse array created by the SPRSIN function.
An n-element right hand vector.
Set this keyword to force the computation to be done in double-precision arithmetic.
; Begin by creating an array A: A = [[ 5.0, 0.0, 0.0], $ [ 3.0, -2.0, 0.0], $ [ 4.0, -1.0, 0.0]] ; Define the right-hand vector: X = [1.0, 2.0, -1.0] ; Convert to sparse format, then multiply by X: result = SPRSAX(SPRSIN(A),X) ; Print the result: PRINT, result
5.00000 -1.00000 2.00000
FULSTR, LINBCG, SPRSAB, SPRSIN, SPRSTP, READ_SPR, WRITE_SPR