Multiply inverse matrix with another one - matlab

Question

I want to multiply two matrices, the first matrix is the inverse of A, and the second matrix is B,
input('Enter The first Matrix')
A = [ 1 2 3 ; 4 5 6 ; 7 8 0 ]
[m n] = size(A)
if m==n
if det(A)==0
disp('inverse does not exist')
else
invv=inv(A)
disp(invv)
end
else
disp('Number of rows and columns are not equel , no inverse')
end
input('Enter The second Matrix')
B = [ 1 ; 1 ; 1 ]
How can I verify that the number of columns in the first matrix is equal to the number of rows in the second matrix, so that they can be multiplied?

Answer 1

function [X] = dot_inv(X,x)
% X - numeric array
% x - cell array of numeric vectors
% DIM - dimensions to omit (asumes ndims(X) = numel(x))
% Y - inner product obtained by summing the products of X and x along DIM
% initialise dimensions
%--------------------------------------------------------------------------
[m n] = size(X)
if m==n
if det(X)==0
error('Error. \n inverse does not exist.')
else
X=inv(X)
end
else
error('Error. \n Number of rows and columns are not equel , no inverse!')
end
if iscell(x)
DIM = (1:numel(x)) + ndims(X) - numel(x);
else
DIM = 1;
x = {x};
end
% inner product using recursive summation (and bsxfun)
%--------------------------------------------------------------------------
for d = 1:numel(x)
s = ones(1,ndims(X));
s(DIM(d)) = numel(x{d});
X = bsxfun(#times,X,reshape(full(x{d}),s));
X = sum(X,DIM(d));
end
% eliminate singleton dimensions
%--------------------------------------------------------------------------
X = squeeze(X);
return