# Revision history [back]

Apparently (unfortunately), there is no way to specify/detect that your objects are sparse when defining the chain complex.

You could try to enforce that by giving as few choice as possible to the ChainComplex by defining bdrs to be sparse matrices explicitely defined over GF(2).

Please tell us if is works. Otherwise, could you please provide your code so that we can handle a concrete example and see what is going on ?