package com.nr.test.test_chapter17;
import static com.nr.test.NRTestUtil.maxel;
import static com.nr.test.NRTestUtil.vecsub;
import static org.junit.Assert.fail;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.nr.ode.*;
import com.nr.sf.Bessjy;
public class Test_StepperBS {
@Before
public void setUp() throws Exception {
}
@After
public void tearDown() throws Exception {
}
@Test
public void test() {
int i,nvar=4;
final double atol=1.0e-6,rtol=atol,h1=0.01,hmin=0.0,x1=1.0,x2=2.0;
double sbeps;
// dydx= new double[nvar], not used
double[] y= new double[nvar],yout= new double[nvar],yexp= new double[nvar];
boolean localflag, globalflag=false;
// Test StepperBS
System.out.println("Testing StepperBS");
Bessjy bess = new Bessjy();
for (i=0;i<nvar;i++) {
y[i]=bess.jn(i,x1);
yexp[i]=bess.jn(i,x2);
}
Output out=new Output(20);
rhs_StepperBS d = new rhs_StepperBS();
StepperBS s = new StepperBS();
Odeint ode = new Odeint(y,x1,x2,atol,rtol,h1,hmin,out,d,s);
ode.integrate();
for (i=0;i<nvar;i++) {
yout[i]=out.ysave[i][out.count-1];
System.out.printf("%f %f\n", yout[i],yexp[i]);
}
sbeps = 1.e-8;
System.out.println(maxel(vecsub(yout,yexp)));
localflag = maxel(vecsub(yout,yexp)) > sbeps;
globalflag = globalflag || localflag;
if (localflag) {
fail("*** StepperBS: Inaccurate integration");
}
if (globalflag) System.out.println("Failed\n");
else System.out.println("Passed\n");
}
class rhs_StepperBS implements DerivativeInf {
public void derivs(final double x,double[] y,double[] dydx) {
dydx[0]= -y[1];
dydx[1]=y[0]-(1.0/x)*y[1];
dydx[2]=y[1]-(2.0/x)*y[2];
dydx[3]=y[2]-(3.0/x)*y[3];
}
public void jacobian(final double x, double[] y, double[] dfdx, double[][] dfdy){}
}
}