ones.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.functions.ExternalFunction;

/**An external function for creating matrices that consist of ones           */
/* (e.g.: ones(2) will return a 2-by-2 matrix [1,2;1,1],                     *
 *  ones(4,3) will return a 4-by-3 matrix of ones                            */
public class ones extends ExternalFunction
{
	/**return a  matrix 
	@param operands[0] = number of rows
	@param operands[1] = number of columns */
	public OperandToken evaluate(Token[] operands)
	{

        // at least one operand
        if (getNArgIn(operands) < 1) 
            throwMathLibException("ones: number of arguments <1 ");
        
        // number of arguments
        int n = getNArgIn(operands);
        
        // set up dimension array
        int[] dim = new int[n];
        
        // only DoubleNumberTokens accepted
        // each token is one dimension
        for (int i=0; i<n; i++)
        {
            if (!(operands[i] instanceof DoubleNumberToken)) 
                throwMathLibException("ones: arguments must be numbers");
            
            // get requested dimension
            dim[i] = (int)((DoubleNumberToken)operands[i]).getValueRe();

            if (dim[i]<0)
                throwMathLibException("ones: dimension <0");

        }
        
        // special case for rand(k)  -> rand(k,k)
        if (dim.length==1)
        {
            int d = dim[0];
            dim = new int[]{d,d};
        }
        
        // ceate array of correct size with dimensions "dim"
        DoubleNumberToken num = new DoubleNumberToken(dim, null, null);
        
        // create "1" value for all values of num
        for (int i=0; i< num.getNumberOfElements(); i++)
        {
            num.setValue(i, 1, 0);
        }
        
        return num;

    } // end eval
}

/*
@GROUP
matrix
@SYNTAX
ones(sizex, sizey)
ones(n,m,k,...)
@DOC
Returns a matrix of ones.
@NOTES
@EXAMPLES
ISNUMERIC(2,3) = [1,1,1;1,1,1]
ISNUMERIC(3,4) = [1,1,1,1;1,1,1,1;1,1,1,1]
@SEE
zeros

*/