[eigen] Eigen Internals

[Mayank Agarwal]

Hi,

I have been going through the core Eigen folder. I am really confused about
the starting point of it all as from which header file I should start
understanding the Eigen internals and function definitions.

Thank You,
Mayank

[Gael Guennebaud]

Hi,

that's a though question! Which part do you want to learn?

Anyhow, a good start could be to run step by step in a debugger the
following code:

#define EIGEN_DONT_VECTORIZE
#include <Eigen/Core>
using namespace Eigen;
int main() {
int n = 5;
VectorXd A(n), B(n), C(n);
A = B+C;
}

This will show you what is returned by A+B, and how this simple expression
is evaluated. You can comment #define EIGEN_DONT_VECTORIZE to see how
explicit vectorization is accomplished or try more fancy expressions.

gael

Post by Mayank Agarwal
Hi,
I have been going through the core Eigen folder. I am really confused
about the starting point of it all as from which header file I should start
understanding the Eigen internals and function definitions.
Thank You,
Mayank

[Mayank Agarwal]

Hi,

Thanks a lot. I am new to Eigen and have been going through documentation
and all.
I want to implement symmetric matrices class in Eigen, for which I guess
knowing the internals
and how Eigen works is required. I am not sure which part to learn and what
parts are there.
I just want to learn enough so that I know what my approach should be to
create such a working
class in Eigen.

Thank you,
Mayank


‌

Post by Gael Guennebaud
Hi,
that's a though question! Which part do you want to learn?
Anyhow, a good start could be to run step by step in a debugger the
#define EIGEN_DONT_VECTORIZE
#include <Eigen/Core>
using namespace Eigen;
int main() {
int n = 5;
VectorXd A(n), B(n), C(n);
A = B+C;
}
This will show you what is returned by A+B, and how this simple expression
is evaluated. You can comment #define EIGEN_DONT_VECTORIZE to see how
explicit vectorization is accomplished or try more fancy expressions.
gael

Post by Mayank Agarwal
Hi,
I have been going through the core Eigen folder. I am really confused
about the starting point of it all as from which header file I should start
understanding the Eigen internals and function definitions.
Thank You,
Mayank