Dear all,

can Eigen deduce its (optimal) return type?

Assume the following code

Code: Select all


typedef Eigen::Array<double,20,1> vector_fixed;

vector_fixed v1,v2;
v1.fill(1.0);
v2.fill(2.0);

// Compute expression (not vector)
auto tmp = v1+v2;

// Create new vector
vector_fixed a(tmp);


In the last line, does the expression tmp contain all information to deduce the (optimal/natural) resulting type?

Best regards,
Matthias

I'm not sure to understand your question, but tmp knows that it best evaluate to a Array<double,20,1> as available by decltype(tmp)::PlainObject which is also the return type of tmp.eval().

ggael wrote:I'm not sure to understand your question, but tmp knows that it best evaluate to a Array<double,20,1> as available by decltype(tmp)::PlainObject which is also the return type of tmp.eval().

This is exactly the function I was looking for. Thank's a lot.