Android Open Source - Calculator-for-Android Test Big Decimal Evaluator

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License

The source code is released under:

Apache License

Java Source Code

//   Copyright 2012 Digipom Inc.
////  w  w w . j ava 2  s.  c o  m
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.

package com.digipom.android.library.evaluator;

import java.math.BigDecimal;

import junit.framework.TestCase;

import com.digipom.android.library.evaluator.PostfixEvaluator.FlatToken;
import com.digipom.android.library.evaluator.exception.ParseException;

public class TestBigDecimalEvaluator extends TestCase {
  // BigDecimal is far slower than float or double, so reduce the # of
  // iterations.
  private static final int RESOLUTION = 16;

  interface ZCommand {
    BigDecimal execute(BigDecimal x, BigDecimal y);
  }

  public void testSimpleEvaluate() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "x + y");

    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return x.add(y);
      }
    });
  }

  public void testMoreComplexEvaluate() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "sin(y) + cos(x)");

    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return new BigDecimal(Math.sin(y.doubleValue()))
            .add(new BigDecimal(Math.cos(x.doubleValue())));
      }
    });
  }

  public void testYetMoreComplexEvaluate() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "pow(abs(cos(x) + cos(y)), 0.5)");
    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return new BigDecimal(Math.pow(
            new BigDecimal(Math.cos(x.doubleValue()))
                .add(new BigDecimal(Math.cos(y.doubleValue())))
                .abs().doubleValue(), 0.5));
      }
    });
  }

  public void testYetMoreComplexEvaluateJava() {
    final BigDecimal[][] result = new BigDecimal[RESOLUTION][RESOLUTION];

    for (int y = 0; y < RESOLUTION; y++) {
      for (int x = 0; x < RESOLUTION; x++) {
        result[y][x] = new BigDecimal(Math.pow(
            new BigDecimal(
                Math.cos(new BigDecimal(x).doubleValue()))
                .add(new BigDecimal(Math.cos(new BigDecimal(y)
                    .doubleValue()))).abs().doubleValue(),
            0.5));
      }
    }
  }

  public void testCaretWithNoSpace() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "x ^ y");
    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return new BigDecimal(
            Math.pow(x.doubleValue(), y.doubleValue()));
      }
    });
  }

  public void testCaretWithNestedExpression() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "abs(cos(x) + cos(y)) ^ 0.5");
    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return new BigDecimal(Math.pow(
            new BigDecimal(Math.cos(x.doubleValue()))
                .add(new BigDecimal(Math.cos(y.doubleValue())))
                .abs().doubleValue(), 0.5));
      }
    });
  }

  public void testNestedCaretsSequential() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "x^y^2");
    // 16 otherwise our numbers get into a ridiculous range.
    testCombos(16, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return new BigDecimal(Math.pow(x.doubleValue(), new BigDecimal(
            Math.pow(y.doubleValue(), 2)).doubleValue()));
      }
    });
  }

  public void testSequentialCarets() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "x^2 * y^2");
    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return (new BigDecimal(Math.pow(x.doubleValue(), 2))
            .multiply(new BigDecimal(Math.pow(y.doubleValue(), 2))));
      }
    });
  }

  public void testCaretPrecedence() throws ParseException {
    BigDecimalPostfixEvaluator evaluator = new BigDecimalPostfixEvaluator(
        "-3^2");

    testCombos(RESOLUTION, evaluator, new ZCommand() {

      @Override
      public BigDecimal execute(BigDecimal x, BigDecimal y) {
        return new BigDecimal(Math.pow(new BigDecimal(3).doubleValue(),
            new BigDecimal(2).doubleValue())).negate();
      }
    });
  }

  private void testCombos(int range, BigDecimalPostfixEvaluator evaluator,
      ZCommand zCommand) throws ParseException {
    FlatToken yIdentifier = evaluator.getIdentifier("y");
    FlatToken xIdentifier = evaluator.getIdentifier("x");

    for (int y = 0; y < range; y++) {
      yIdentifier.bigDecimalValue = BigDecimal.valueOf(y);

      for (int x = 0; x < range; x++) {
        xIdentifier.bigDecimalValue = BigDecimal.valueOf(x);

        assertEquals(
            zCommand.execute(new BigDecimal(x), new BigDecimal(y))
                .doubleValue(), evaluator.evaluate()
                .doubleValue(), 0.001);
      }
    }
  }
}

Java Source Code List

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