On Tuesday 05 October 2004 15:19, Kasper Peeters <kasper.peeters@aei.mpg.de wrote:
I need to handle extremely large sparse matrices, of approximately half a million square elements (with, typically, on the order of 5 million non-zero entries).
The following, however, fails on a machine where std::size_t is 4 bytes long:
#include <boost/numeric/ublas/matrix_sparse.hpp> int main () { using namespace boost::numeric::ublas; sparse_matrix<double> m(400000, 400000); }
I assume this is uBLAS from Boost 1.31.0 If that is the case the short answer is that you need a more recent uBLAS. The current Boost CVS HEAD will do. These overflow problem have been fix for a few months. Longer answer. Don't forget that uBLAS has several sparse format to choose from. You may find coordinate_matrix or compress_matrix more suitable then sparse_matrix. Your problem is very large and to get efficient solutions you may need to exploit any structure it has!
It fails with
Assertion failed in file boost/numeric/ublas/functional.hpp at line 1345: The overflow test BOOST_UBLAS_CHECK ((size1 * size2) / size1 == size2, bad_size ()); is quite amusing. It actually checks if the calculation has not already overflowed, with a small chance of a false positive.
Michael -- ___________________________________ Michael Stevens Systems Engineering 34128 Kassel, Germany Navigation Systems, Estimation and Bayesian Filtering http://bayesclasses.sf.net ___________________________________