Re: [eigen] Using transpose in expressions

On Tue, Mar 29, 2016 at 5:33 PM, Gael Guennebaud <gael.guennebaud@xxxxxxxxx> wrote:

Hi,

thank you for finding this issue. It's surprising that it has not been discovered earlier. I've already a fix in blas_traits that I'll push after more testing...products...

gael

On Sat, Mar 26, 2016 at 9:23 PM, Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
I can confirm this, also on 3.2.8 and 3.2-head. It does work on the 3.3 branch, however (which has a significantly different evaluator structure).

I don't know how to best fix this (I'm not _that_ familiar with Eigen's internals).
Meanwhile, you can work-around this by by adding an .eval() before or after the .transpose()

Christoph

On 2016-03-26 13:51, Brad Bell wrote:

Why does the following program work when ERROR_CASE is zero and
generates a compile error when ERROR_CASE is one
(I am using eigen-3.2.7).

# include <iostream>
# include <Eigen/Core>
# define ERROR_CASE 1
int main(void)
{ typedef Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic> matrix;
//
matrix A = matrix::Identity(2, 2);
# if ERROR_CASE
matrix C = A * (A * A).transpose();
# else
matrix C = A * A * A.transpose();
# endif
//
std::cout << "C = \n" << C << "\n";
}

--
Dipl. Inf., Dipl. Math. Christoph Hertzberg

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