Как написать процедуру для умножения двух матриц, используя клен

Question

Визит http://www.mapleprimes.com/questions/35644-Multiply-2-Matrices-In-Maple-Using-A-Procedure

Answer 1

restart:

mmm:=proc(a::Matrix,b::Matrix)
local c, i, j, k, m, n, p;
(m,n,p):=op([1,1],a), op([1,2],b), op([1,2],a);
if op([1,1],b) <> p then error "incompatible dimensions"; end if;
c:=Matrix(m,n);
for i from 1 to m do
   for j from 1 to n do
      c[i,j] := add(a[i,k]*b[k,j],k=1..p);
   end do;
end do:
c;
end proc:

a:=LinearAlgebra:-RandomMatrix(2,3):
b:=LinearAlgebra:-RandomMatrix(3,5):

mmm(a,b);
a.b; # check

mmm(a,a^%T);
a.a^%T; # check

mmm(b,a); # test for dimension mismatch
b.a; # test for dimension mismatch

a:=LinearAlgebra:-RandomMatrix(33,33):
b:=LinearAlgebra:-RandomMatrix(33,33):
LinearAlgebra:-Norm(a.b - mmm(a,b));