I am using eigen 2.0.2 in an Xcode project with
#define EIGEN_DEFAULT_TO_ROW_MAJOR 1
in a common prefix header plus
#include "../Eigen/Core"
#import "../Eigen/LU" // Objective-C++
USING_PART_OF_NAMESPACE_EIGEN
as well.

In the online Tutorial, it states that
mat1.corner(TopLeft)
should be legal but I had to change this to
mat1.corner(Eigen::TopLeft)
to satisfy the compiler.

is this as it should be?

I have the same question wrt execution time. In debug mode, my runtime is about 25x the runtime with -O3 optimization and NDEBUG turned on! This seems excessive. [FWIW, the runtime on an Intel Mac is significantly faster than on a PPC Mac.]

mpmcl wrote:I am using eigen 2.0.2 in an Xcode project with
#define EIGEN_DEFAULT_TO_ROW_MAJOR 1
in a common prefix header plus
#include "../Eigen/Core"
#import "../Eigen/LU" // Objective-C++
USING_PART_OF_NAMESPACE_EIGEN
as well.

In the online Tutorial, it states that
mat1.corner(TopLeft)
should be legal but I had to change this to
mat1.corner(Eigen::TopLeft)
to satisfy the compiler.

is this as it should be?

Yes. TopLeft is in namespace Eigen.

I have the same question wrt execution time. In debug mode, my runtime is about 25x the runtime with -O3 optimization and NDEBUG turned on! This seems excessive.

This is how it is with heavy c++ code. We've been experiencing the same. But -O2 is in many cases enough.