このコードがnullポインタ例外をスローするのはなぜですか？私はJavaの初心者なので、この間違いに精通していません。それについて読みましたが、バグを取り除くことができませんでした...複素行列DFTにベクトルを掛けたいです。
public class Naloga {
/**
* @param args
*/
public static void main(String[] args) {
double polinom1[] = {1,1,0,1};
double polinom2[] = {1,1,0,1};
int n=4;
//System.out.println(n);
int newN=2*n-1;
//zapis matrike dft
Complex dft[][]=new Complex [newN][newN];
Complex omega = new Complex(Math.cos((2*Math.PI)/newN),Math.sin((2*Math.PI)/newN));
for (int j=0;j<newN;j++){
for (int k=0;k<n;k++){
dft[j][k] = omega.pow((j*k)%newN);
//System.out.println(dft[j][k]);
}
}
//System.out.println("To je pol1:");
//dopolnitev do n2
double pol1[]=new double[newN];
for (int i=0;i<newN;i++){
if (i<n){
pol1[i]=polinom1[i];
}
else{
pol1[i]=0;
}
//System.out.println(pol1[i]);
}
//mnozenje polinoma z dft
Complex p1[] = new Complex[newN];
for (int i=0;i<newN;i++){
Complex sum = new Complex(0,0);
for(int k=0;k<n;k++){
for(int j=0;j<newN;j++){
sum=sum.plus(dft[i][j].times(pol1[k]));
System.out.println(sum);
}
}
p1[i]=sum;
System.out.println(p1[i]+" ");
}
}
}
class Complex{
double re;
double im;
public Complex(double real, double imag) {
re = real;
im = imag;
}
public String toString() {
double tRe = (double)Math.round(re * 100000) / 100000;
double tIm = (double)Math.round(im * 100000) / 100000;
if (tIm == 0) return tRe + "";
if (tRe == 0) return tIm + "i";
if (tIm < 0) return tRe + "-" + (-tIm) + "i";
return tRe + "+" + tIm + "i";
}
// sestevanje
public Complex plus(Complex b) {
Complex a = this;
double real = a.re + b.re;
double imag = a.im + b.im;
return new Complex(real, imag);
}
// odstevanje
public Complex minus(Complex b) {
Complex a = this;
double real = a.re - b.re;
double imag = a.im - b.im;
return new Complex(real, imag);
}
// mnozenje z drugim kompleksnim stevilo
public Complex times(Complex b) {
Complex a = this;
double real = a.re * b.re - a.im * b.im;
double imag = a.re * b.im + a.im * b.re;
return new Complex(real, imag);
}
// mnozenje z realnim stevilom
public Complex times(double alpha) {
return new Complex(alpha * re, alpha * im);
}
// reciprocna vrednost kompleksnega stevila
public Complex reciprocal() {
double scale = re*re + im*im;
return new Complex(re / scale, -im / scale);
}
// deljenje
public Complex divides(Complex b) {
Complex a = this;
return a.times(b.reciprocal());
}
// e^this
public Complex exp() {
return new Complex(Math.exp(re) * Math.cos(im), Math.exp(re) * Math.sin(im));
}
//potenca komplesnega stevila
public Complex pow(int k) {
Complex c = new Complex(1,0);
for (int i = 0; i <k ; i++) {
c = c.times(this);
}
return c;
}
}