Boost C++ Libraries: Ticket #4410: Sparse/Packed matrix assignment needs type conversion

attachment set

Thu, 08 Jul 2010 14:55:35 GMT

attachment → matrix_assign_problem.cpp

A sample program for showing the problem (the program should not compile).

Thu, 08 Jul 2010 15:02:39 GMT

I propose a possible patch (see attachment: matrix_assign-packed_sparse_storage-type_conversion.patch).

Essentially,

Expressions of the first type might be changed by casting an E::value_type to a M::value_type, like in this way:
```
  if (static_cast<value_type>(v) != value_type/*zero*/())
```

Obviously, this does not work when E::value_type and M::value_type are not castable (e.g., std::complex and double, respectively).

Expressions of the second type might be changed in 2 ways:

Option A (the one used in the proposed patch)

  typedef typename matrix_traits<E>::value_type expr_value_type;
  functor_type::apply(*it, expr_value_type/*zero*/()); // NOTE: use of E::value_type in place of M::value_type

Option B

  typedef F<typename M::..., value_type> functor_type; // NOTE: use M::value_type instead of E::value_type
  functor_type::apply(*it, value_type/*zero*/()); // unchanged

attachment set

Thu, 08 Jul 2010 15:04:09 GMT

attachment → matrix_assign-packed_sparse_storage-type_conversion.patch

Possible solution.

Thu, 08 Jul 2010 15:08:40 GMT

There is also a companion post un uBLAS ml:

http://lists.boost.org/MailArchives/ublas/2010/07/4420.php

owner, status changed

David Bellot — Mon, 16 Aug 2010 22:01:18 GMT

owner changed from Gunter to David Bellot
status new → assigned

David Bellot — Mon, 16 Aug 2010 22:03:09 GMT

applied patch from Marco Guazzone. Should be OK, however it raises a concern about a possible security hole with static_cast<>, only when people are crazy enough to use ublas as a data storage having nothing to do with linear algebra (like I did once ;-) )

status changed; resolution set

David Bellot — Mon, 16 Aug 2010 22:12:10 GMT

status assigned → closed
resolution → worksforme

attachment set

Tue, 17 Aug 2010 08:30:39 GMT

attachment → test_ticket4410.cpp

Test case: test copy-construction/-assignement of a sparse (symmetric) matrix. The test fails to compile if the patch is not applied.