inversematrix.java

JAVA 数学程序库 提供常规的数值计算程序包

package jmathlib.toolbox.jmathlib.matrix;

import jmathlib.core.tokens.numbertokens.DoubleNumberToken;
import jmathlib.core.tokens.Token;
import jmathlib.core.tokens.OperandToken;
import jmathlib.core.tokens.MatrixToken;
import jmathlib.core.functions.ExternalFunction;
import jmathlib.core.interpreter.Errors;
import jmathlib.core.tokens.FunctionToken;
import jmathlib.core.functions.Function;

/**An external function for determining the determinant of a matrix*/
public class inversematrix extends ExternalFunction
{
	/**Check that the parameter is a square matrix then calculate
	it's inverse
	It uses the Determinant and Adjoint classes to calculate the 
	determinant and the adjoint*/
	public OperandToken evaluate(Token[] operands)
	{
	    if (getNArgIn(operands) != 1)
			throwMathLibException("InverseMatrix: number of arguments != 1");

		FunctionToken token = null;
		Function determinant = null;
		Function adjoint = null;

		OperandToken result = null;
		Token operand = operands[0];
		
		if(operand instanceof DoubleNumberToken)
		{
			DoubleNumberToken matrix = ((DoubleNumberToken)operand);
			
			if(matrix.getSizeX() == matrix.getSizeY())
			{
				int size = matrix.getSizeX();

				try
				{
					token = new FunctionToken("Determinant");
					determinant = getFunctionManager().findFunction(token);
				}
				catch(java.lang.Exception e)
				{}

				try
				{
					token = new FunctionToken("Adjoint");
					adjoint = getFunctionManager().findFunction(token);
				}
				catch(java.lang.Exception e)
				{}
			
				double matrixDeterminant = ((DoubleNumberToken)determinant.evaluate(operands)).getValueRe();
				
				if(matrixDeterminant != 0)
				{
					DoubleNumberToken matrixAdjoint = ((DoubleNumberToken)adjoint.evaluate(operands));
					
					double[][] values = matrixAdjoint.getReValues();
					
					for(int rowNumber = 0; rowNumber < size; rowNumber++)
					{
						for(int colNumber = 0; colNumber < size; colNumber++)
						{
							values[rowNumber][colNumber] = values[rowNumber][colNumber] / matrixDeterminant;
						}
					}
					result = new DoubleNumberToken(values);
				}
		        else
		        {
		            jmathlib.core.interpreter.Errors.throwMathLibException(ERR_MATRIX_SINGULAR);
		        }			
			}
	        else
	        {
	            jmathlib.core.interpreter.Errors.throwMathLibException(ERR_NOT_SQUARE_MATRIX);
	        }			
		}
		
		return result;
	}
}

/*
@GROUP
matrix
@SYNTAX
answer=INVERSEMATRIX(square matrix)
@DOC
Returns the inverse of the first operand, which must be a square matrix.
@NOTES
@EXAMPLES
INVERSEMATRIX([1,0;0,1]) = [1,0;0,1]
@SEE
adjoint, simultaneouseq
*/