Hello,

Thank you for the wonderful library.

I am having issues with the householder QR factorization and I am not sure how to resolve the issue.
The householder Qr factorization on a 1 column matrix produces an assert saying number of rows or number of columns are not equal. However it works fine if the number of columns are more than 1.

This is the exact error that I recieve
-----------------------------------------------------------------
Eigen/src/Core/CwiseBinaryOp.h:141: Eigen::CwiseBinaryOp<BinaryOp, Lhs, Rhs>::CwiseBinaryOp(const Lhs&, const Rhs&, const BinaryOp&) [with BinaryOp = Eigen::ei_scalar_product_op<double, double>, Lhs = Eigen::Transpose<Eigen::Transpose<Eigen::Block<Eigen::Block<Eigen::Block<Eigen::Matrix<double, 5, 1, 0, 5, 1>, -0x00000000000000001, -0x00000000000000001, false, true>, -0x00000000000000001, 1, true, true>, -0x00000000000000001, 1, false, true> > >, Rhs = Eigen::Block<Eigen::Block<Eigen::Block<Eigen::Matrix<double, 5, 1, 0, 5, 1>, -0x00000000000000001, -0x00000000000000001, false, true>, -0x00000000000000001, -0x00000000000000001, false, true>, -0x00000000000000001, -0x00000000000000001, false, true>]: Assertion `lhs.rows() == rhs.rows() && lhs.cols() == rhs.cols()' failed.
----------------------------------------------------------------------

The sample code that reproduces this issue is below


Matrix<double,5,2> test2;
test2<<1,2,3,4,5,6,7,8,9,10;
cout<<test2<<"\r\n";
cout<<test2.householderQr().matrixQR().eval()<<"\r\n"; //This works

Matrix<double,5,1> test;
test<<1,2,3,4,5;
cout<<test<<"\r\n";
cout<<test.householderQr().matrixQR().eval()<<"\r\n"; //This produces an assert saying number of rows and number of columns are not equal.

The equivalent result from Matlab is shown below

For the 5x2 matrix - This output is same as Eigen's result
qr([1,2;3,4;5,6;7,8;9,10])

-12.8452 -14.7915
0.2167 -1.1010
0.3611 -0.0438
0.5056 -0.3347
0.6500 -0.6257

and for the 5x1 matrix, - Eigen produces an assert error and fails
qr([1;2;3;4;5])
-7.4162
0.2376
0.3565
0.4753
0.5941

The configuration:
Eigen 3.0 beta 2
OS: Ubuntu 10.10 x64
CPU: Intel Core 2 Quad
Compiler: GCC 4.4.5 with Codeblocks IDE
Build: Issue present in both Debug and Release build.

Since, I don't really need the householder reflectors, I would be happy even if I can extract the elements of the R matrix under all conditions.

Thanks

Regards
Sri

Thanks, can you please file a bug report.

Wow!. Thank you for the quick reply!. I have filed a bug report. Is there anything that I can do in the short term?

Regards
Sri

I'll look at your bug ASAP.

Thank you!. It's fixed now.