Ticket #4410 (closed Patches: worksforme)
Sparse/Packed matrix assignment needs type conversion
Reported by: | Marco Guazzone <marco.guazzone@…> | Owned by: | david.bellot |
---|---|---|---|
Milestone: | To Be Determined | Component: | uBLAS |
Version: | Boost Development Trunk | Severity: | Problem |
Keywords: | Cc: |
Description
In file boost/detail/matrix_assign.hpp there are two possible source of type-conversion error interesting both sparse and packed matrices.
Let:
typedef typename M::value_type value_type; typedef F<typename M::..., typename E::value_type> functor_type;
Then:
- Comparison of an E::value_type with an M::value_type
if (v != value_type/*zero*/()) // where v is of type E::value_type
E.g., E::value_type is std::complex<float> and M::value_type is std::complex<double>.
- Assignment of an M::value_type to an E::value_type
E.g., E::value_type is float and M::value_type is std::complex<float>.
functor_type::apply(*it, value_type/*zero*/());
Attachments
Change History
Changed 6 years ago by Marco Guazzone <marco.guazzone@…>
- attachment matrix_assign_problem.cpp added
comment:1 Changed 6 years ago by Marco Guazzone <marco.guazzone@…>
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
Changed 6 years ago by Marco Guazzone <marco.guazzone@…>
- attachment matrix_assign-packed_sparse_storage-type_conversion.patch added
Possible solution.
comment:2 Changed 6 years ago by Marco Guazzone <marco.guazzone@…>
There is also a companion post un uBLAS ml:
comment:3 Changed 6 years ago by david.bellot
- Owner changed from guwi17 to david.bellot
- Status changed from new to assigned
comment:4 Changed 6 years ago by david.bellot
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 ;-) )
comment:5 Changed 6 years ago by david.bellot
- Status changed from assigned to closed
- Resolution set to worksforme
Changed 6 years ago by Marco Guazzone <marco.guazzone@…>
- attachment test_ticket4410.cpp added
Test case: test copy-construction/-assignement of a sparse (symmetric) matrix. The test fails to compile if the patch is not applied.
A sample program for showing the problem (the program should not compile).