Saving memory by reusing a variable name?

I have a code that uses pretty large files which causes some memory problems.

In my code I have a very large sparse matrix X, which I then multiply by a small dense matrix A. My question is, does the code:

Y=AX; clear X;

use less space when compared with:

X=AX;

[Oliver Woodford]

I think you mean A*X (in MATLAB syntax).

Answer 1

[Matt Tearle]

I'd guess they'd be the same. Matrix multiply requires having to make an intermediate variable anyway (behind the scenes, if not explicitly).