complex.h

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#ifndef __COMPLEX_H
#define __COMPLEX_H

#include <cmath>
#include <cstdio>

double epsilon= 0.0000001;

struct complex { double r; double i;};

complex czero = {0,0};

complex cmul(complex a,complex b)
{ 
        complex r;
        r.r=a.r*b.r-a.i*b.i;
        r.i=a.i*b.r+a.r*b.i;
        return r;
}

complex cadd(complex a,complex b)
{
        complex r;
        r.r=a.r+b.r;
        r.i=a.i+b.i;
        return r;
}

complex csub(complex a,complex b)
{
        complex r;
        r.r=a.r-b.r;
        r.i=a.i-b.i;
        return r;
}

complex r2c(double x)
{
        complex r;
        r.r=x;
        r.i=0;
        return r;
}

bool isEqual(complex a,complex b)
{
        return ((a.r==b.r)&&(a.i==b.i));
}

bool isEqualE(complex a,complex b)
{
        return ((abs(a.r-b.r)<epsilon)&&(abs(a.i-b.i)<epsilon));
}

complex cpow(complex a,int b)
{
        complex r;
    r=a;
        for (int i=1;i<b;i++) r=cmul(r,a);
        return r;
}

complex cdiv(complex a,complex b)
{
        complex r;
        double B=b.r*b.r+b.i*b.i;
        r.r=(a.r*b.r+a.i*b.i)/B;
        r.i=(a.i*b.r-a.r*b.i)/B;
        return r;
}

complex cexp(complex a){
        complex r;
        double length,angle;
        length=exp(a.r);
        angle=a.i;
        r.r=cos(angle)*length;
        r.i=sin(angle)*length;
        return r;
}

complex cln(complex a){
        complex r;
        double length,angle;
        length=sqrt(a.r*a.r+a.i*a.i);
        angle=atan2(a.i,a.r);
        r.r=log(length);
        r.i=angle;
        return r;
}

complex cneg(complex a){
        complex r;
        r.r=-a.r;
        r.i=-a.i;
        return r;
}

complex cpos(complex a){
        return a;
}

complex csqrt(complex a)
{
        complex r;
        double length,angle;
        length=sqrt(sqrt(a.r*a.r+a.i*a.i));
        angle=atan2(a.i,a.r)/2;
        r.r=cos(angle)*length;
        r.i=sin(angle)*length;
        return r;
}

void cprint(complex c)
{
        printf("%f",c.r);
        if (c.i>0) printf("+%fi",c.i);
        if (c.i<0) printf("%fi",c.i);
        printf("\n");
}

bool isReal(complex x)
{
                return (abs(x.i)<=epsilon);
}
#endif