39 lines
766 B
C++
39 lines
766 B
C++
#include "nr.h"
|
|
|
|
void NR::mpmul(Vec_O_UCHR &w, Vec_I_UCHR &u, Vec_I_UCHR &v)
|
|
{
|
|
const DP RX=256.0;
|
|
int j,n_max,nn=1;
|
|
DP cy,t;
|
|
|
|
int n=u.size();
|
|
int m=v.size();
|
|
int p=w.size();
|
|
n_max=MAX(m,n);
|
|
while (nn < n_max) nn <<= 1;
|
|
nn <<= 1;
|
|
Vec_DP a(0.0,nn),b(0.0,nn);
|
|
for (j=0;j<n;j++) a[j]=u[j];
|
|
for (j=0;j<m;j++) b[j]=v[j];
|
|
realft(a,1);
|
|
realft(b,1);
|
|
b[0] *= a[0];
|
|
b[1] *= a[1];
|
|
for (j=2;j<nn;j+=2) {
|
|
b[j]=(t=b[j])*a[j]-b[j+1]*a[j+1];
|
|
b[j+1]=t*a[j+1]+b[j+1]*a[j];
|
|
}
|
|
realft(b,-1);
|
|
cy=0.0;
|
|
for (j=nn-1;j>=0;j--) {
|
|
t=b[j]/(nn >> 1)+cy+0.5;
|
|
cy=(unsigned long) (t/RX);
|
|
b[j]=t-cy*RX;
|
|
}
|
|
if (cy >= RX) nrerror("cannot happen in mpmul");
|
|
for (j=0;j<p;j++) w[j]=0;
|
|
w[0]=(unsigned char) cy;
|
|
for (j=1;j<MIN(n+m,p);j++)
|
|
w[j]=(unsigned char) b[j-1];
|
|
}
|