How multiprecision optimizes allocation?

From: Andy (borucki.andrzej_at_[hidden])
Date: 2019-11-05 06:12:25

I have tested boost::mulitprecision::cpp_int
and have tested simplest algorithm for int multiplication
My test method is several times slower than boost multiplication because I
resized product vector to size fist + size second. This allocation take
most time, if I use static array on stack, it will be fast for small
numbers. What is the riddle of fast comnputing z = x*y in loop for quite
small x and y in Boost cpp_int?