| Re: [eigen] Specializing max_coeff_visitor for some number types |
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On Mon, 7 Apr 2014, Marc Glisse wrote:
As you can see in LU, there is a subtlety I hadn't thought of: max(abs) was
returning a RealScalar, not a Scalar. That's not a big problem when we only
want to compare it with 0.
Note that we end up computing twice as many abs() as before, because we
store the coefficient in the visitor and not the result of abs. Avoiding
it would be possible, adding a new unary functor that defaults to
scalar_abs_op, storing its result_type in the visitor, calling it before
passing the result to better_coeff_op, and making better_coeff_op work on
this new type. But that's starting to get a bit complicated for such a
simple feature...
--
Marc Glisse