complex.h

实现FFT功能的强大源码

#include<math.h>
struct complex {
	double x;
	double y;
};
complex cmplx(double x,double y)
{
	complex z;
	z.x=x;z.y=y;
	return z;
}
complex conjg(complex z)
{
	return cmplx(z.x,-z.y);
}

complex cadd(complex a,complex b)
{
	return cmplx(a.x+b.x,a.y+b.y);
}
complex csub(complex a,complex b)
{
	return cmplx(a.x-b.x,a.y-b.y);
}
complex cmul(complex a,complex b)
{
	return cmplx(a.x*b.x-a.y*b.y,a.x*b.y+a.y*b.x);
}
complex rmul(double a,complex z)
{
	return cmplx(a*z.x,a*z.y);
}
complex cdiv(complex a,complex b)
{
	double D=b.x*b.x+b.y*b.y;
	return cmplx((a.x*b.x+a.y*b.y)/D,(a.y*b.x-a.x*b.y)/D);
}
complex rdiv(complex z,double a)
{
	return cmplx(z.x/a,z.y/a);
}
double real(complex z)
{
	return z.x;
}
double aimag(complex z)
{
	return z.y;
}
complex cexp(complex z)
{
	double R=exp(z.x);
	return cmplx(R*cos(z.y),R*sin(z.y));
}