[eigen] Assignment to MatrixBase fails assertion or SEGVs

[Robert Lupton the Good <rhl@xxxxxxxxxxxxxxxxxxx>]

In general, eigen sets the lhs to the size of the rhs.

This assignment using MatrixBase compiles nicely but fails at run time:
Assertion failed: (rows() == other.rows() && cols() == other.cols()),  
function lazyAssign, file /u/lsst/products/DarwinX86/eigen/2.0.9/ 
include/Eigen/src/Core/Assign.h, line 406.

If you use static-sized arrays, you get a SEGV (g++ 4.3.4; os/x 10.6)

(I care because of the way that SWIG generates code (see yesterday's  
problems);  I have almost everything working --- at least if you only  
want one type of Eigen arrays (e.g. float, RowMajor) playing with  
numpy at a time)

				R


#include "Eigen/Core.h"

using namespace Eigen;

int main() {
#if 0
    MatrixBase<Matrix2f> noinit;
    Matrix2f mat;
#else
    MatrixBase<MatrixXf> noinit;
    MatrixXf mat(2, 2);
#endif

    noinit = mat;
}