Hi,
I want to change the values of matrix based on some logical masking.
Is there any efficient way of in-place modification method instead of using unaryexpr and std::for_each individual member access.
Say change Identity matrix I to -I by logical condition, if coefficient =1 change to -1.
Thanks,

The closest is select (mimics C++ ternary operator):

http://eigen.tuxfamily.org/dox/classEig ... 2e40d1ef6e