src/mantissa/tests-src/org/spaceroots/mantissa/functions/scalar/ComputableFunctionSamplerTest.java

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package org.spaceroots.mantissa.functions.scalar;

import org.spaceroots.mantissa.functions.FunctionException;

import junit.framework.*;

public class ComputableFunctionSamplerTest
  extends TestCase {

  public ComputableFunctionSamplerTest(String name) {
    super(name);
  }

  public void testBeginStepNumber()
    throws FunctionException {

    ComputableFunctionSampler sampler =
      new ComputableFunctionSampler(new Function(0.0, 1.0),
                                    0.0, 0.099, 11);

    assertTrue(sampler.size() == 11);
    assertTrue(Math.abs(sampler.samplePointAt(0).getX()  - 0.000) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(0).getY()  - 0.000) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(5).getX()  - 0.495) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(5).getY()  + 0.495) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(10).getX() - 0.990) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(10).getY() + 0.990) < 1.0e-10);

  }

  public void testRangeNumber()
    throws FunctionException {

    double[] range = new double[2];
    range[0] = 0.0;
    range[1] = 1.0;
    ComputableFunctionSampler sampler =
      new ComputableFunctionSampler(new Function(0.0, 1.0), range, 11);

    assertTrue(sampler.size() == 11);
    assertTrue(Math.abs(sampler.samplePointAt(0).getX()  - 0.0) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(0).getY()  - 0.0) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(5).getX()  - 0.5) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(5).getY()  + 0.5) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(10).getX() - 1.0) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(10).getY() + 1.0) < 1.0e-10);

  }

  public void testRangeStepNoAdjust()
    throws FunctionException {

    double[] range = new double[2];
    range[0] = 0.0;
    range[1] = 1.0;
    ComputableFunctionSampler sampler =
      new ComputableFunctionSampler(new Function(0.0, 1.0),
                                    range, 0.083, false);

    assertTrue(sampler.size() == 12);
    assertTrue(Math.abs(sampler.samplePointAt(0).getX()  - 0.000) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(0).getY()  - 0.000) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(5).getX()  - 0.415) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(5).getY()  + 0.415) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(11).getX() - 0.913) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(11).getY() + 0.913) < 1.0e-10);

  }

  public void testRangeStepAdjust()
    throws FunctionException {

    double[] range = new double[2];
    range[0] = 0.0;
    range[1] = 1.0;
    ComputableFunctionSampler sampler =
      new ComputableFunctionSampler(new Function(0.0, 1.0),
                                    range, 0.083, true);

    assertTrue(sampler.size() == 13);
    assertTrue(Math.abs(sampler.samplePointAt(0).getX()  - 0.0) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(0).getY()  - 0.0) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(6).getX()  - 0.5) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(6).getY()  + 0.5) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(12).getX() - 1.0) < 1.0e-10);
    assertTrue(Math.abs(sampler.samplePointAt(12).getY() + 1.0) < 1.0e-10);

  }

  public void testOutOfRange()
    throws FunctionException {

    ComputableFunctionSampler sampler =
      new ComputableFunctionSampler(new Function(0.0, 1.0), 0.0, 1.0, 10);

    boolean exceptionOccurred = false;
    try {
      sampler.samplePointAt(-1);
    } catch(ArrayIndexOutOfBoundsException e) {
      exceptionOccurred = true;
    }
    assertTrue(exceptionOccurred);

    exceptionOccurred = false;
    try {
      sampler.samplePointAt(10);
    } catch(ArrayIndexOutOfBoundsException e) {
      exceptionOccurred = true;
    }
    assertTrue(exceptionOccurred);

  }

  public void testUnderlyingException() {

    ComputableFunctionSampler sampler =
      new ComputableFunctionSampler(new ExceptionGeneratingFunction(),
                                    0.0, 0.1, 11);

    boolean exceptionOccurred = false;
    try {
      sampler.samplePointAt(2);
    } catch(FunctionException e) {
      exceptionOccurred = true;
    }
    assertTrue(! exceptionOccurred);

    exceptionOccurred = false;
    try {
      sampler.samplePointAt(8);
    } catch(FunctionException e) {
      exceptionOccurred = true;
    }
    assertTrue(exceptionOccurred);

  }

  public static Test suite() {
    return new TestSuite(ComputableFunctionSamplerTest.class);
  }

  private static class Function
    implements ComputableFunction {

    private static final long serialVersionUID = -7173012970400285826L;
    private double min;
    private double max;

    public Function(double min, double max) {
      this.min = min;
      this.max = max;
    }

    public double valueAt(double x)
      throws FunctionException {

      if (x < min || x > max) {
        throw new FunctionException("outside of range");
      }

      return -x;

    }

  }

  private static class ExceptionGeneratingFunction
  implements ComputableFunction {
    private static final long serialVersionUID = 7853080602731012102L;
    public double valueAt(double x)
      throws FunctionException {
      if (x < 0.5) {
        return -x;
      }
      throw new FunctionException("upper half range exception");
    }
  }

}