ref: fce29312cd3c8240c39e1e7915ef7d6c1e334a7c dir: /libnpe/exp2.c/
#include <math.h> #include "_npe.h" double exp2(double x) { static double ln2c = 0.0; if(ln2c == 0.0) ln2c = log(2.0); return exp(x*ln2c); }