uBLAS matrix clear memory

Question

I have a uBLAS matrix, like so:

boost::numeric::ublas::matrix<double> mat(50000,50000);

Once I'm done with a set of calculations on the matrix, I want its memory freed.

I have been using mat.clear() which, according to the docs, "clears the matrix". But my program keeps running out of memory.

Digging into the headers, I find this:

void clear () {
  std::fill (data ().begin (), data ().end (), value_type/*zero*/());
}

So there's a clear semantics problem with clear().

The question then is, how do I ensure that the memory is freed?

Did you find a solution to this problem? I seem to be running into he same issue. An in-elegant way of handling the issue would be resizing the matrix to (0,0). I was wondering if there is a "right" way to do it. — Devil, Aug 26 '15 at 16:19
@Devil, but is resizing guaranteed to release memory? For instance, with `std::vector` a resize does not make such a guarantee since the vector may be enlarged again later and allocations are expensive. Instead, the C++11 `shrink_to_fit()` function must be used. I never did find an adequate solution to this problem and eventually switched to using an std::vector of std::vectors since I mostly wanted uBLAS as a handy 2d matrix. — Richard, Aug 27 '15 at 06:28

score 0 · Answer 1 · edited Sep 08 '13 at 20:30

0

An inelegant way to return the memory is by resizing the matrix:

mat.resize(0,0,false);

Though I have not tried using zero for a size value myself...

edited Sep 08 '13 at 20:30

Kamil Budziewski

answered Sep 08 '13 at 19:57

user2759605

1 Answers1