mirror of
https://gitlab.com/libeigen/eigen.git
synced 2024-12-21 07:19:46 +08:00
294f5f16dd
also split into several pages for better reusability (more generally useful than just for this assert)
78 lines
2.7 KiB
Plaintext
78 lines
2.7 KiB
Plaintext
namespace Eigen {
|
|
|
|
/** \page UnalignedArrayAssert Explanation of the assertion on unaligned arrays
|
|
|
|
Hello! You are seeing this webpage because your program terminated on an assertion failure like this one:
|
|
<pre>
|
|
my_program: path/to/eigen2/Eigen/src/Core/MatrixStorage.h:44:
|
|
Eigen::ei_matrix_array<T, Size, MatrixOptions, Align>::ei_matrix_array()
|
|
[with T = double, int Size = 2, int MatrixOptions = 2, bool Align = true]:
|
|
Assertion `(reinterpret_cast<size_t>(array) & 0xf) == 0 && "this assertion
|
|
is explained here: http://eigen.tuxfamily.org/api/UnalignedArrayAssert.html
|
|
**** READ THIS WEB PAGE !!! ****"' failed.
|
|
</pre>
|
|
|
|
There are 3 known causes for this issue. Please read on to understand them and learn how to fix them.
|
|
|
|
\b Table \b of \b contents
|
|
- \ref c1
|
|
- \ref c2
|
|
- \ref c3
|
|
- \ref explanation
|
|
|
|
\section c1 Cause 1: Structures having Eigen objects as members
|
|
|
|
If you have code like this,
|
|
|
|
\code
|
|
class Foo
|
|
{
|
|
//...
|
|
Eigen::Vector2d v;
|
|
//...
|
|
};
|
|
//...
|
|
Foo *foo = new Foo;
|
|
\endcode
|
|
|
|
then you need to read this separate page: \ref StructHavingEigenMembers "Structures Having Eigen Members".
|
|
|
|
Note that here, Eigen::Vector2d is only used as an example, more generally the issue arises for all \ref FixedSizeVectorizable "fixed-size vectorizable Eigen types".
|
|
|
|
\section c2 Cause 2: STL Containers
|
|
|
|
If you use STL Containers such as std::vector, std::map, ..., with Eigen objects, like this,
|
|
|
|
\code
|
|
std::vector<Eigen::Matrix2f> my_vector;
|
|
std::map<int, Eigen::Matrix2f> my_map;
|
|
\endcode
|
|
|
|
then you need to read this separate page: \ref StlContainers "Using STL Containers with Eigen".
|
|
|
|
Note that here, Eigen::Matrix2f is only used as an example, more generally the issue arises for all \ref FixedSizeVectorizable "fixed-size vectorizable Eigen types".
|
|
|
|
\section c3 Cause 3: Passing Eigen objects by value
|
|
|
|
If some function in your code is getting an Eigen object passed by value, like this,
|
|
|
|
\code
|
|
void func(Eigen::Vector4d v);
|
|
\endcode
|
|
|
|
then you need to read this separate page: \ref PassingByValue "Passing Eigen objects by value to functions".
|
|
|
|
Note that here, Eigen::Vector4d is only used as an example, more generally the issue arises for all \ref FixedSizeVectorizable "fixed-size vectorizable Eigen types".
|
|
|
|
\section explanation General explanation of this assertion
|
|
|
|
\ref FixedSizeVectorizable "fixed-size vectorizable Eigen objects" must absolutely be created at 16-byte-aligned locations, otherwise SIMD instructions adressing them will crash.
|
|
|
|
Eigen normally takes care of these alignment issues for you, by setting an alignment attribute on them and by overloading their "operator new".
|
|
|
|
However there are a few corner cases where these alignment settings get overridden: they are the possible causes for this assertion.
|
|
|
|
*/
|
|
|
|
}
|