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JEP is a Java library for parsing and evaluating mathematical expressions.
/* @author rich
* Created on 09-Mar-2004
*/
package org.lsmp.djep.groupJep.values;
import org.lsmp.djep.groupJep.groups.AlgebraicExtension;
/**
* An element of the algrabraic extension K(t).
* a0 + a1 t + a(n-1) t^(n-1)
* where t is defined to be the the solution of a polynomial equation.
*
* @see AlgebraicExtension
* @author Rich Morris
* Created on 09-Mar-2004
*/
public class AlgebraicExtensionElement extends FreeGroupElement {
AlgebraicExtension ae;
/**
* An element of the algebraic extension K(t).
* a0 + a1 t + a(n-1) t^(n-1)
* where t is defined to be the the solution of a polynomial equation.
* If the degree of the polynomial specified by coeffs is greater
* than n then the polynomial will be reduced by using
* the equation t^n = .....
* @param K the algebraic extension.
* @param coeffs array of coefficients for this algebraic number. c0 + c1 t + ... + cn t^n
*/
public AlgebraicExtensionElement(AlgebraicExtension K, Number coeffs[])
{
super(K,coeffs);
this.ae = K;
int deg_p = ae.getPoly().getDegree();
while(this.getCoeffs().length > deg_p)
{
Polynomial poly2 = ae.getSubsPoly();
int deg_c = this.getCoeffs().length-1;
// coeffs = (a_m s^(m-n)+...+a_n) s^n + (a_(n-1) s^(n-1)+...+a_0)
// = p1 * s^n + p2;
// = p2 - p1 * q;
Number p1Coeffs[] = new Number[deg_c-deg_p+1];
Number p2Coeffs[] = new Number[deg_p];
System.arraycopy(this.getCoeffs(),deg_p,p1Coeffs,0,deg_c-deg_p+1);
System.arraycopy(this.getCoeffs(),0,p2Coeffs,0,deg_p);
Polynomial p1 = new Polynomial(ae.getBaseRing(),ae.getPoly().getSymbol(),p1Coeffs);
Polynomial p2 = new Polynomial(ae.getBaseRing(),ae.getPoly().getSymbol(),p2Coeffs);
Polynomial p3 = p1.mul(poly2);
Polynomial p4 = p3.add(p2);
super.setCoeffs(p4.getCoeffs());
}
}
/** sub classes should overwrite this to make the correct type. */
protected Polynomial valueOf(Number lcoeffs[])
{
AlgebraicExtensionElement g = new AlgebraicExtensionElement(ae,lcoeffs);
return g;
}
}