casting without rounding using coder

How can I manually trigger casting from a float/double to integer without involving any rounding while using coder?
LUT = single(rand(1,2000)*200);
for i=1:2000
ind = int32(LUT(i));
fprintf("%i\n",ind);
end
When the C++ code is generated it will be similar to:
int ind = static_cast<int>(rt_roundf_snf(LUT[i]));
I am aware that under certain circumstances coder is able to automatically figure out the optimal datatypes for indexing inside for loops resulting then in the desired result:
int ind = static_cast<int>(LUT[i]);

Réponses (1)

Bjorn Gustavsson
Bjorn Gustavsson le 12 Juil 2022
Well, the only interpretation I can thing of that matches the "casting without rounding" in a sensible way is:
ind = int32(floor(LUT2(i));
That way ind will be the integer part of whatever LUT2 is. But this is still "rounding-off the fractional part".
HTH

4 commentaires

Marc Barnada
Marc Barnada le 15 Juil 2022
Unfortunately my interest is to simply trigger a plain static_cast<int> call without flooring, ceiling or rounding.
Bjorn Gustavsson
Bjorn Gustavsson le 15 Juil 2022
What is the crucial difference?
Marc Barnada
Marc Barnada le 18 Juil 2022
I want to have highly efficient C++ code, and that extra call to rt_roundf_snf has a big impact in the timings of a Look-Up-Table (LUT) function.
Bjorn Gustavsson
Bjorn Gustavsson le 18 Juil 2022
If it is a limited point-of-use and a one-time effort would it be possible to manually edit the generated code?

Connectez-vous pour commenter.

Catégories

En savoir plus sur MATLAB Coder dans Centre d'aide et File Exchange

Produits

Version

R2021a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by