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Tree polynominal expand #31

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393e502
[Release] v0.1
DonMat Jun 20, 2016
d9985ed
Added Expander and ExpanderTests
Jun 27, 2016
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149 changes: 149 additions & 0 deletions src/main/java/pl/jagiellonian/implementation/Expander.java
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package pl.jagiellonian.implementation;

import pl.jagiellonian.interfaces.ITreeExpression;
import pl.jagiellonian.interfaces.IVariable;
import pl.jagiellonian.utils.Operation;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

public class Expander {

/**
* @param iTreeExpression - {@link ITreeExpression} expression to expand
* @return {@link ITreeExpression} expanded polynomial
*/
public ITreeExpression expand(ITreeExpression iTreeExpression) {
return divideIntoMonomials(iTreeExpression);
}

private ITreeExpression divideIntoMonomials(ITreeExpression iTreeExpression) {
ITreeExpression child0 = (ITreeExpression) iTreeExpression.getChildren().get(0);
ITreeExpression child1 = (ITreeExpression) iTreeExpression.getChildren().get(1);

List<Double> firstList;
List<Double> secondList = convertToDoubleArray(new ArrayList<>(), 0, child1);

if(isMultiplication(child0)) {
firstList = convertToDoubleArray(new ArrayList<>(), 0, divideIntoMonomials(child0));
}
else {
firstList = convertToDoubleArray(new ArrayList<>(), 0, child0);
}

return convertToTreePolynomial(multiplyCoefficients(firstList, secondList));
}

private boolean isMultiplication(ITreeExpression iTreeExpression) {
return iTreeExpression.getOperation() == Operation.MULT;
}


private List<Double> convertToDoubleArray(List<Double> list, int depth, ITreeExpression iTreeExpression) {
List<IVariable> listChildren = iTreeExpression.getChildren();

if(depth == 0) { //wyraz wolny
Operation sign = iTreeExpression.getOperation();
IVariable iVariable = listChildren.get(1);
double doubleVar = Double.parseDouble(iVariable.toString());
if(sign == Operation.SUB) {
doubleVar = - doubleVar;
}
list.add(doubleVar);
ITreeExpression next = (ITreeExpression) listChildren.get(0);
convertToDoubleArray(list, ++depth, next);
}
else if (depth == 1) { // x
ITreeExpression ite = (ITreeExpression) iTreeExpression.getChildren().get(0);
if(isNumber(ite)) {
list.add(Double.parseDouble(ite.getAllNodes().get(0).toString()));
}
else {
ITreeExpression var = (ITreeExpression) listChildren.get(1);
list.add(Double.parseDouble(var.getAllNodes().get(0).toString()));
ITreeExpression next = (ITreeExpression) listChildren.get(0);
convertToDoubleArray(list, ++depth, next);
}
}
else {
if(listChildren.size() == 1) {
ITreeExpression ite = (ITreeExpression) iTreeExpression.getChildren().get(0);
ITreeExpression var1 = (ITreeExpression) ite.getChildren().get(0);
list.add(Double.parseDouble(var1.getAllNodes().get(0).toString()));
return list;
}
else {
ITreeExpression ite = (ITreeExpression) iTreeExpression.getChildren().get(0);
if (!isNumber(ite)) {
ITreeExpression var = (ITreeExpression) listChildren.get(1);
ITreeExpression var1 = (ITreeExpression) var.getChildren().get(0);
list.add(Double.parseDouble(var1.getAllNodes().get(0).toString()));
ITreeExpression next = (ITreeExpression) listChildren.get(0);
convertToDoubleArray(list, ++depth, next);
} else {
ITreeExpression var = (ITreeExpression) listChildren.get(0);
list.add(Double.parseDouble(var.getAllNodes().get(0).toString()));
return list;
}
}
}
return list;
}

private ITreeExpression convertToTreePolynomial(List<Double> list) {
Collections.reverse(list);
int degree = list.size() - 1;

Iterator it = list.iterator();
ITreeExpression iTreeExpression = null;

while(it.hasNext()) {
ITreeExpression variable;

if(degree == 0) {
variable = new TreeExpression(Operation.ADD, new Variable(it.next().toString()));
}
else if (degree == 1) {
ITreeExpression value = new TreeExpression(Operation.ADD, new Variable(it.next().toString()));
variable = value.mult("x");
}
else {
ITreeExpression value = new TreeExpression(Operation.ADD, new Variable(it.next().toString()));
variable = new TreeExpression(Operation.POW, new Variable("x"));
variable = variable.pow(degree + "");
variable = value.mult(variable);
}

degree--;

if(iTreeExpression == null) {
iTreeExpression = new TreeExpression(Operation.ADD, variable);
}
else {
iTreeExpression = iTreeExpression.add(variable);
}
}

return iTreeExpression;
}

private boolean isNumber(ITreeExpression iTreeExpression) {
return iTreeExpression.getAllNodes().size() == 1;
}

private List<Double> multiplyCoefficients(List<Double> first, List<Double> second){
int totalLength = first.size() + second.size() - 1;
List<Double> resultAsArray = new ArrayList<>(totalLength);
double[] result = new double[totalLength];
for (int i = 0; i < first.size(); i++)
for (int j = 0; j < second.size(); j++) {
result[i + j] += first.get(i) * second.get(j);
}
for(double d: result){
resultAsArray.add(d);
}
return resultAsArray;
}
}
7 changes: 7 additions & 0 deletions src/main/java/pl/jagiellonian/interfaces/ITreeExpression.java
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@@ -1,5 +1,7 @@
package pl.jagiellonian.interfaces;

import pl.jagiellonian.utils.Operation;

import java.util.List;

/**
Expand All @@ -19,6 +21,11 @@ public interface ITreeExpression extends IVariable {
ITreeExpression setParenthesis();

Boolean getParenthesis();

Operation getOperation();

List<IVariable> getChildren();

int degree(IVariable variable);
int degree(List<IVariable> variables);
}
115 changes: 115 additions & 0 deletions src/test/java/pl/jagiellonian/TreeExpressionExpanderTest.java
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package pl.jagiellonian;

import org.junit.Test;
import pl.jagiellonian.implementation.Expander;
import pl.jagiellonian.implementation.TreeExpression;
import pl.jagiellonian.implementation.Variable;
import pl.jagiellonian.interfaces.ITreeExpression;
import pl.jagiellonian.utils.Operation;

import static org.junit.Assert.assertEquals;

public class TreeExpressionExpanderTest {

@Test
public void twoComponentsTest() {
ITreeExpression tree = new TreeExpression(Operation.ADD, new Variable("1"));
tree = tree.mult("x");
tree = tree.sub("2");
ITreeExpression tree2 = new TreeExpression(Operation.ADD, new Variable("1"));
tree2 = tree2.mult("x");
tree2 = tree2.add("6");
tree = tree.mult(tree2);
Expander expander = new Expander();
String expected = "(1.0)*(x)^2+(4.0)*x+-12.0";

assertEquals(expected, expander.expand(tree).toString());
}

@Test
public void threeComponentsTest() {
ITreeExpression tree = new TreeExpression(Operation.ADD, new Variable("1"));
tree = tree.mult("x");
tree = tree.sub("2");
ITreeExpression tree2 = new TreeExpression(Operation.ADD, new Variable("1"));
tree2 = tree2.mult("x");
tree2 = tree2.add("6");
ITreeExpression tree3 = new TreeExpression(Operation.SUB, new Variable("6"));
tree3 = tree3.mult("x");
tree3 = tree3.sub("5");
tree = tree.mult(tree2);
tree = tree.mult(tree3);
Expander expander = new Expander();
String expected = "(6.0)*(x)^3+(19.0)*(x)^2+(-92.0)*x+60.0";

assertEquals(expected, expander.expand(tree).toString());
}

@Test
public void fourComponentsTest() {
ITreeExpression tree = new TreeExpression(Operation.ADD, new Variable("-6"));
tree = tree.mult("x");
tree = tree.sub("24");
ITreeExpression tree2 = new TreeExpression(Operation.ADD, new Variable("1"));
tree2 = tree2.mult("x");
tree2 = tree2.sub("10");
ITreeExpression tree3 = new TreeExpression(Operation.ADD, new Variable("6"));
tree3 = tree3.mult("x");
tree3 = tree3.sub("3");
ITreeExpression tree4 = new TreeExpression(Operation.ADD, new Variable("-2"));
tree4 = tree4.mult("x");
tree4 = tree4.sub("5");
tree = tree.mult(tree2);
tree = tree.mult(tree3);
tree = tree.mult(tree4);
Expander expander = new Expander();
String expected = "(72.0)*(x)^4+(-288.0)*(x)^3+(-3834.0)*(x)^2+(-5220.0)*x+3600.0";

assertEquals(expected, expander.expand(tree).toString());
}

@Test
public void multipleComponentsTest() {
ITreeExpression tree = new TreeExpression(Operation.ADD, new Variable("-1"));
tree = tree.mult("x");
tree = tree.add("6");
ITreeExpression tree2 = new TreeExpression(Operation.ADD, new Variable("-2"));
tree2 = tree2.mult("x");
tree2 = tree2.add("4");
ITreeExpression tree3 = new TreeExpression(Operation.ADD, new Variable("6"));
tree3 = tree3.mult("x");
tree3 = tree3.sub("13");
ITreeExpression tree4 = new TreeExpression(Operation.ADD, new Variable("-4"));
tree4 = tree4.mult("x");
tree4 = tree4.add("5");
ITreeExpression tree5 = new TreeExpression(Operation.ADD, new Variable("-3"));
tree5 = tree5.mult("x");
tree5 = tree5.sub("2");
ITreeExpression tree6 = new TreeExpression(Operation.ADD, new Variable("2"));
tree6 = tree6.mult("x");
tree6 = tree6.add("10");
ITreeExpression tree7 = new TreeExpression(Operation.ADD, new Variable("1"));
tree7 = tree7.mult("x");
tree7 = tree7.add("2");
ITreeExpression tree8 = new TreeExpression(Operation.ADD, new Variable("-5"));
tree8 = tree8.mult("x");
tree8 = tree8.sub("3");
ITreeExpression tree9 = new TreeExpression(Operation.ADD, new Variable("1"));
tree9 = tree9.mult("x");
tree9 = tree9.add("11");
tree = tree.mult(tree2);
tree = tree.mult(tree3);
tree = tree.mult(tree4);
tree = tree.mult(tree5);
tree = tree.mult(tree6);
tree = tree.mult(tree7);
tree = tree.mult(tree8);
tree = tree.mult(tree9);
Expander expander = new Expander();
String expected = "(-1440.0)*(x)^9+(-11304.0)*(x)^8+(97516.0)*(x)^7+(408068.0)*(x)^6" +
"+(-1491980.0)*(x)^5+(-1924636.0)*(x)^4+(5544544.0)*(x)^3+(2407712.0)*(x)^2+(-4178880.0)*x+-2059200.0";

assertEquals(expected, expander.expand(tree).toString());
}

}