Matrix multiplication: Difference between revisions

<lang rexx>/*REXX program multiplies two matrixes together, shows matrixes & result*/

x.=

do r=1 while x.r\=='' /*build the "A" matric from X. #s*/

do c=1 while x.r\==''; parse var x.r a.r.c x.r; end

end

y.=

do r=1 while y.r\=='' /*build the "B" matric from Y. #s*/

do c=1 while y.r\==''; parse var y.r b.r.c y.r; end

end

c.=0; L=0 /*L is the ma width element value*/

do i =1 for Arows /*multiply matrix A & B ──► C */

do j =1 for Bcols

c.i.j = c.i.j + a.i.k * b.k.j; L=max(L,length(c.i.j))

exit /*stick a fork in it, we're done.*/

/*──────────────────────────────────SHOWMAT subroutine──────────────────*/

showMat: parse arg mat,rows,cols; say

say center(mat 'matrix',cols*(L+1)+4,"─")

do r =1 for rows; _=

do c=1 for cols; _=_ right(value(mat'.'r'.'c),L); end; say _

end

return</lang>

'''output'''

<pre style="overflow:scroll">

─A matrix─

──B matrix───

──C matrix───