137 lines
4.9 KiB
Java
137 lines
4.9 KiB
Java
package rules;
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/*
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SETTINGS: (please don't move this part)
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PATH=ExpandRule1
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*/
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import it.cavallium.warppi.math.Function;
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import it.cavallium.warppi.math.FunctionOperator;
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import it.cavallium.warppi.math.MathContext;
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import it.cavallium.warppi.math.functions.Multiplication;
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import it.cavallium.warppi.math.functions.Number;
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import it.cavallium.warppi.math.functions.Subtraction;
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import it.cavallium.warppi.math.functions.Sum;
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import it.cavallium.warppi.math.functions.SumSubtraction;
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import it.cavallium.warppi.math.rules.Rule;
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import it.cavallium.warppi.math.rules.RuleType;
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import it.unimi.dsi.fastutil.objects.ObjectArrayList;
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/**
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* Expand rule
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* -(+a+b) = -a-b
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* -(+a-b) = -a+b
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*
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* @author Andrea Cavalli
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*
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*/
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public class ExpandRule1 implements Rule {
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// Rule name
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@Override
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public String getRuleName() {
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return "ExpandRule1";
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}
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// Rule type
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@Override
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public RuleType getRuleType() {
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return RuleType.EXPANSION;
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}
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/* Rule function
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Returns:
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- null if it's not executable on the function "f"
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- An ObjectArrayList<Function> if it did something
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*/
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@Override
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public ObjectArrayList<Function> execute(final Function f) {
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boolean isExecutable = false;
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if (f instanceof Multiplication) {
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final Multiplication fnc = (Multiplication) f;
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if (fnc.getParameter1().equals(new Number(fnc.getMathContext(), -1))) {
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final Function expr = fnc.getParameter2();
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if (expr instanceof Sum)
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isExecutable = true; // -1 * (a + b)
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else if (expr instanceof Subtraction)
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isExecutable = true; // -1 * (a - b)
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else if (expr instanceof SumSubtraction)
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isExecutable = true; // -1 * (a +- b)
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}
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} else if (f instanceof Subtraction || f instanceof SumSubtraction) {
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final FunctionOperator fnc = (FunctionOperator) f;
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final Function expr = fnc.getParameter2();
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if (expr instanceof Sum)
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isExecutable = true; // x [- +-] (a + b)
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else if (expr instanceof Subtraction)
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isExecutable = true; // x [- +-] (a - b)
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else if (expr instanceof SumSubtraction)
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isExecutable = true; // x [- +-] (a +- b)
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}
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if (isExecutable) {
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final ObjectArrayList<Function> result = new ObjectArrayList<>();
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final MathContext root = f.getMathContext();
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Function expr = null; // f.getParameter1() [* - +-] expr
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int fromSubtraction = 0; // 0: (*), 1: (-), 2: (+-)
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FunctionOperator subtraction = null;
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if (f instanceof Multiplication)
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expr = ((Multiplication) f).getParameter2();
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else if (f instanceof Subtraction || f instanceof SumSubtraction) {
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expr = ((FunctionOperator) f).getParameter2();
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if (f instanceof Subtraction)
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fromSubtraction = 1;
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else
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fromSubtraction = 2;
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}
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if (f instanceof SumSubtraction) {
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}
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final Function fnc = expr;
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if (fnc instanceof Sum) {
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final Function a = ((Sum) fnc).getParameter1();
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final Function b = ((Sum) fnc).getParameter2();
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final Function fnc2 = new Subtraction(root, new Multiplication(root, new Number(root, -1), a), b);
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if (fromSubtraction > 0) {
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// FIXME SumSubtraction treated as just Subtraction
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subtraction = new Sum(root, ((FunctionOperator) f).getParameter1(), fnc2);
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result.add(subtraction); // x [- +-] (a + b) -> x + (-1*a - b)
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} else
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result.add(fnc2); // -1 * (a + b) -> -1*a - b
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} else if (fnc instanceof Subtraction) {
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final Function a = ((Subtraction) fnc).getParameter1();
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final Function b = ((Subtraction) fnc).getParameter2();
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final Function fnc2 = new Sum(root, new Multiplication(root, new Number(root, -1), a), b);
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if (fromSubtraction > 0) {
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// FIXME SumSubtraction treated as just Subtraction
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subtraction = new Sum(root, ((FunctionOperator) f).getParameter1(), fnc2);
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result.add(subtraction); // x [- +-] (a - b) -> x + (-1*a + b)
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} else
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result.add(fnc2); // -1 * (a - b) -> -1*a + b
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} else if (fnc instanceof SumSubtraction) { // FIXME Subtraction and SumSubtraction confusion
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final Function a = ((SumSubtraction) fnc).getParameter1();
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final Function b = ((SumSubtraction) fnc).getParameter2();
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final Function fnc2 = new Sum(root, new Multiplication(root, new Number(root, -1), a), b); // -1*a + b
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final Function fnc3 = new Subtraction(root, new Multiplication(root, new Number(root, -1), a), b); // -1*a - b
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if (fromSubtraction > 0) {
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// x [- +-] (a +- b) -> [x +- (-1*a + b), x +- (-1*a - b), x +- (-1*a - b)]
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subtraction = new SumSubtraction(root, ((FunctionOperator) f).getParameter1(), fnc2);
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result.add(subtraction);
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subtraction = new SumSubtraction(root, ((FunctionOperator) f).getParameter1(), fnc3);
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// FIXME same result twice
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result.add(subtraction);
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result.add(subtraction);
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} else {
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// -1 * (a +- b) -> [-1*a + b, -1*a + b]
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// FIXME same result twice
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result.add(fnc2);
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result.add(fnc2);
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}
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}
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return result;
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} else
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return null;
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}
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}
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