com.scudata.expression.fn.algebra.Polyfit Maven / Gradle / Ivy

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SPL(Structured Process Language) A programming language specially for structured data computing.
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package com.scudata.expression.fn.algebra;

import com.scudata.common.Logger;
import com.scudata.common.MessageManager;
import com.scudata.common.RQException;
import com.scudata.dm.Context;
import com.scudata.dm.Sequence;
import com.scudata.expression.Function;
import com.scudata.expression.IParam;
import com.scudata.resources.EngineMessage;

/**
 * ????????polyfit(A,B,n)????n?ζ???ʽ???????X??Y
 * ͨ???ⷨ???̻?ö???ʽϵ??
 * @author bd
 */
public class Polyfit extends Function {
	/**
	 * ??????ʽ????Ч?ԣ???Ч???׳??쳣
	 */
	public void checkValidity() {
		if (param == null) {
			MessageManager mm = EngineMessage.get();
			throw new RQException("polyfit" + mm.getMessage("function.missingParam"));
		}
	}

	public Object calculate(Context ctx) {
		if (param.isLeaf()) {
			MessageManager mm = EngineMessage.get();
			throw new RQException("polyfit" + mm.getMessage("function.invalidParam"));
		} else {
			if (param.getSubSize() != 3) {
				MessageManager mm = EngineMessage.get();
				throw new RQException("polyfit" + mm.getMessage("function.invalidParam"));
			}

			IParam sub1 = param.getSub(0);
			IParam sub2 = param.getSub(1);
			IParam sub3 = param.getSub(2);
			if (sub1 == null || sub2 == null || sub3 == null) {
				MessageManager mm = EngineMessage.get();
				throw new RQException("polyfit" + mm.getMessage("function.invalidParam"));
			}
			
			Object o1 = sub1.getLeafExpression().calculate(ctx);
			Object o2 = sub2.getLeafExpression().calculate(ctx);
			Object o3 = sub3.getLeafExpression().calculate(ctx);
			if (o1 instanceof Sequence && o2 instanceof Sequence && o3 instanceof Number) {
				int n = ((Number) o3).intValue();
				if (n < 1) {
					n = 1;
				} 
				Sequence A = (Sequence) o1;
				Sequence B = (Sequence) o2;
				int size = A.length();
				if (size != B.length()) {
					// ??ͬά
					MessageManager mm = EngineMessage.get();
					Logger.warn("polyfit" + mm.getMessage("function.paramTypeError"));
					return null;
				}
				double[] as = new double[size];
				double[] bs = new double[size];
				for (int i = 1; i <= size; i++) {
					Object o = A.get(i);
					if (o instanceof Number) {
						as[i-1] = ((Number) o).doubleValue();
					}
					o = B.get(i);
					if (o instanceof Number) {
						bs[i-1] = ((Number) o).doubleValue();
					}
				}
				
				Matrix P = new Matrix(n+1, n+1);
				double[][] ps = P.getArray();
				Matrix Y = new Matrix(n+1, 1);
				double[][] ys = Y.getArray();
				for (int i = 0; i < n+1; i++) {
					for (int j = 0; j < n+1; j++) {
						if (i > j) {
							// ?Ѿ????????
							ps[i][j] = ps[j][i];
						}
						else {
							// ?Խ????ϼ????????ǵ?ϵ??
							double p = 0;
							for (int k = 0; k < size; k++) {
								p += Math.pow(as[k], i+j);
							}
							ps[i][j] = p;
						}
					}
					double p = 0;
					for (int k = 0; k < size; k++) {
						p += Math.pow(as[k], i) * bs[k];
					}
					ys[i][0] = p;
				}
				Matrix X = P.solve(Y);
				if (X == null) {
					return null;
				}
				return X.toSequence(option, false);
			} else {
				MessageManager mm = EngineMessage.get();
				throw new RQException("polyfit" + mm.getMessage("function.paramTypeError"));
			}
		}
	}
}