Hi Toby,
> For most of the PyViennaCL functions, where the prototypes are > compatible, I pass vector_base objects to ViennaCL, because that way I > don't have to have a large number of identical functions for vector, > vector_proxy, etc. In this case, I was passing the vector as a > vector_base object to the solver, and for some reason, it became 0 along > the way. It seems like you found a bug. In the iterative solvers we have the lines: VectorType result = rhs; viennacl::traits::clear(result); If VectorType is viennacl::vector, everything is okay. However, if VectorType is viennacl::vector_base, then a missing copy-CTOR results in a compiler-generated, 'flat' copy. The subsequent clear() thus operates on the memory handle copied from 'rhs', clearing the data. Ticket created: https://github.com/viennacl/viennacl-dev/issues/60 > Does anyone know why that might be? This doesn't seem to happen > elsewhere.. (Notably, for instance, the direct solvers work, and those > calls use matrix_base and vector_base prototypes). Hmm, seems like this requires some temporary to fix things up. Could you please create a temporary object rhs_copy of type viennacl_vector<> and pass that to the iterative solvers? For example, replace result = viennacl::solve(A, b, cg_tag()); by viennacl::vector<T> b_copy(b); result = viennacl::solve(A, b_copy, cg_tag()); The additional temporary object won't matter for overall performance. Best regards, Karli ------------------------------------------------------------------------------ Managing the Performance of Cloud-Based Applications Take advantage of what the Cloud has to offer - Avoid Common Pitfalls. Read the Whitepaper. http://pubads.g.doubleclick.net/gampad/clk?id=121054471&iu=/4140/ostg.clktrk _______________________________________________ ViennaCL-devel mailing list ViennaCL-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/viennacl-devel