package com.nr.test.test_chapter12;
import static com.nr.NRUtil.buildVector;
import static com.nr.fft.FFT.four1;
import static com.nr.test.NRTestUtil.maxel;
import static com.nr.test.NRTestUtil.ranvec;
import static com.nr.test.NRTestUtil.vecsub;
import static java.lang.Math.acos;
import static java.lang.Math.cos;
import static java.lang.Math.sin;
import static org.junit.Assert.fail;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.nr.ran.Ran;
public class Test_four1 {
@Before
public void setUp() throws Exception {
}
@After
public void tearDown() throws Exception {
}
@Test
public void test() {
int i,N=256;
double sbeps=1.e-14,pi=acos(-1.0);
double[] data1 = new double[2*N];
boolean localflag=false, globalflag=false;
// Test four1
System.out.println("Testing four1");
Ran myran = new Ran(17);
// Round-trip test for reals
for (i=0;i<N;i++) {
data1[2*i]=myran.doub();
data1[2*i+1]=0.0;
}
double[] data2=buildVector(data1);
for (i=0;i<2*N;i++) data2[i] /= N;
four1(data2,1);
four1(data2,-1);
localflag = localflag || maxel(vecsub(data1,data2)) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** four1: Round-trip test for random real values failed");
}
// Round-trip test for imaginaries
for (i=0;i<N;i++) {
data1[2*i]=0.0;
data1[2*i+1]=myran.doub();
}
for (i=0;i<2*N;i++) data2[i]=data1[i]/N;
four1(data2,1);
four1(data2,-1);
localflag = localflag || maxel(vecsub(data1,data2)) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** four1: Round-trip test for random imaginary values failed");
}
// Round-trip test for complex numbers
ranvec(data1);
for (i=0;i<2*N;i++) data2[i]=data1[i]/N;
four1(data2,1);
four1(data2,-1);
localflag = localflag || maxel(vecsub(data1,data2)) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** four1: Round-trip test for random complex values failed");
}
// Test delta-function in to sine-wave out, forward transform
for (i=0;i<2*N;i++) data1[i]=0.0;
data1[2*5]=1.0;
four1(data1,1);
for (i=0;i<N;i++) {
data2[2*i]=cos(2.0*pi*5*i/N);
data2[2*i+1]=sin(2.0*pi*5*i/N);
// System.out.printf(setw(15) << data1[2*i] << " " << setw(15) << data1[2*i+1] << " " << setw(15) << data2[2*i] << " " << setw(15) << data2[2*i+1]);
}
localflag = localflag || maxel(vecsub(data1,data2)) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** four1: Forward transform of a chosen delta function did not give expected result");
}
// Test delta-function in to sine-wave out, backward transform
for (i=0;i<2*N;i++) data1[i]=0.0;
data1[2*7]=1.0;
four1(data1,-1);
for (i=0;i<N;i++) {
data2[2*i]=cos(2.0*pi*7*i/N);
data2[2*i+1]=-sin(2.0*pi*7*i/N);
// System.out.printf(setw(15) << data1[2*i] << " " << setw(15) << data1[2*i+1] << " " << setw(15) << data2[2*i] << " " << setw(15) << data2[2*i+1]);
}
localflag = localflag || maxel(vecsub(data1,data2)) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** four1: Backward transform of a chosen delta function did not give expected result");
}
if (globalflag) System.out.println("Failed\n");
else System.out.println("Passed\n");
}
}