jscl.math.function.trigonometric.Cos Maven / Gradle / Ivy

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package jscl.math.function.trigonometric;

import jscl.math.*;
import jscl.math.function.Constants;
import jscl.math.function.Exp;
import jscl.math.function.Trigonometric;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

public class Cos extends Trigonometric {
	public Cos(Generic generic) {
		super("cos", new Generic[]{generic});
	}

	public Generic antiDerivative(int n) throws NotIntegrableException {
		return new Sin(parameters[0]).selfExpand();
	}

	public Generic derivative(int n) {
		return new Sin(parameters[0]).selfExpand().negate();
	}

	public Generic selfExpand() {
		final Generic result = trySimplify();

		if (result != null) {
			return result;
		} else {
			return expressionValue();
		}
	}

	@Nullable
	private Generic trySimplify() {
		Generic result = null;

		if (parameters[0].signum() < 0) {
			result = new Cos(parameters[0].negate()).selfExpand();
		} else if (parameters[0].signum() == 0) {
			result = JsclInteger.valueOf(1);
		} else if (parameters[0].compareTo(Constants.Generic.PI) == 0) {
			result = JsclInteger.valueOf(-1);
		}

		return result;
	}

	public Generic selfElementary() {
		return new Exp(
				Constants.Generic.I.multiply(parameters[0])
		).selfElementary().add(
				new Exp(
						Constants.Generic.I.multiply(parameters[0].negate())
				).selfElementary()
		).multiply(Constants.Generic.HALF);
	}

	public Generic selfSimplify() {
		final Generic result = trySimplify();

		if (result != null) {
			return result;
		} else {

			try {
				Variable v = parameters[0].variableValue();
				if (v instanceof Acos) {
					Generic g[] = ((Acos) v).getParameters();
					return g[0];
				}
			} catch (NotVariableException e) {
			}
			return identity();
		}
	}

	public Generic identity(Generic a, Generic b) {
		return new Cos(a).selfSimplify().multiply(
				new Cos(b).selfSimplify()
		).subtract(
				new Sin(a).selfSimplify().multiply(
						new Sin(b).selfSimplify()
				)
		);
	}

	public Generic selfNumeric() {
		return ((NumericWrapper) parameters[0]).cos();
	}

	@Nonnull
	public Variable newInstance() {
		return new Cos(null);
	}
}