Re: [eigen] Lazy evaluation and adjoint(): Bug?

[Peter <list@xxxxxxxxxxxxxxxxx>]

Dear Gael,



Am 14.09.2016 um 18:43 schrieb Gael Guennebaud:

> but do you really need a custom complex type instead of using std::complex<custom> ? I know that the standard says it's undefined, but in practice it just work as expected. I guess it is left undefined because it's just too
> difficult to thoroughly specify the behavior on a type that you don't known. The same goes for our  matrix decompositions.

Presumably I could overload all operations also for  std::complex<custom>,
but I got beaten up by 'undefined behaviour' too often in my life (*), so I'm just scared.
I just don't know what optimizers do.

All the best
Peter

(*)
P.S. One innocent looking example is the following code snippet

double x;
double y;

x=y; //undefined behavior
x=1;
f(x);

Although x was only used when initialized, it lead to a segfault far away at a completely different code segment,
nevertheless in practice that usually works.