org.lsmp.djep.groupJep.groups.FreeGroup Maven / Gradle / Ivy
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/* @author rich
* Created on 09-Mar-2004
*/
package org.lsmp.djep.groupJep.groups;
import org.lsmp.djep.groupJep.interfaces.*;
import org.lsmp.djep.groupJep.values.*;
import org.nfunk.jep.*;
import org.nfunk.jep.type.*;
import java.util.*;
/**
* A free group generated by a symbol t.
*
* @author Rich Morris
* Created on 09-Mar-2004
*/
public class FreeGroup extends Group implements RingI {
protected RingI baseRing;
protected FreeGroupElement zeroPoly;
protected FreeGroupElement unitPoly;
protected FreeGroupElement tPoly; // t
protected String symbol;
protected Complex rootVal=new Complex(Double.NaN);
/**
* Create the ring K(t) where t is a free variable.
*
* @param K the Ring this is an extension of.
* @param symbol the name of the free variable.
*/
public FreeGroup(RingI K,String symbol) {
super();
this.symbol = symbol;
this.baseRing=K;
// construct the zero poly
zeroPoly = new FreeGroupElement(this,new Number[]{
baseRing.getZERO()});
// construct the unit poly
unitPoly = new FreeGroupElement(this,new Number[]{
baseRing.getONE()});
// construct the polynomial t
tPoly = new FreeGroupElement(this,new Number[]{
baseRing.getZERO(),
baseRing.getONE()});
}
public Number add(Number a,Number b)
{
return ((FreeGroupElement) a).add((FreeGroupElement) b);
}
public Number sub(Number a,Number b)
{
return ((FreeGroupElement) a).sub((FreeGroupElement) b);
}
public Number mul(Number a,Number b)
{
return ((FreeGroupElement) a).mul((FreeGroupElement) b);
}
public boolean equals(Number a,Number b)
{
return ((FreeGroupElement) a).equals((FreeGroupElement) b);
}
public Number valueOf(String s) {
Number coeffs[] = new Number[]{baseRing.valueOf(s)};
return valueOf(coeffs);
}
public Number valueOf(Number coeffs[]) {
return new FreeGroupElement(this, coeffs);
}
public Number getZERO() { return zeroPoly; }
public Number getONE() { return unitPoly; }
public Number getTPoly() { return tPoly; }
public Number getInverse(Number a) {
return sub(zeroPoly,a);
}
public void addStandardConstants(JEP j)
{
baseRing.addStandardConstants(j);
SymbolTable st = j.getSymbolTable();
for(Enumeration en=st.elements();en.hasMoreElements();)
{
Variable val = (Variable) en.nextElement();
st.remove(val.getName());
Number num = (Number) val.getValue();
Number p = this.valueOf(new Number[]{
num});
j.addConstant(val.getName(),p);
}
j.addConstant(symbol,tPoly);
}
public String toString()
{
return baseRing.toString() +"["+symbol+"]";
}
/** Returns the base ring of this extension. */
public RingI getBaseRing() {
return baseRing;
}
/** Sets the value used to approximate the root as a complex number. */
public void setRootVal(Complex complex) {
rootVal = complex;
}
/** Sets the root value for given symbol.
*
* @param sym the symbol to set
* @param val the complex value
* @return true is sym is a symbol for either this group or its baseRing or the basrRing's baseRing etc.
*/
public boolean setRootVal(String sym,Complex val) {
if(symbol.equals(sym))
{
rootVal = val;
return true;
}
else if(baseRing instanceof FreeGroup)
return ((FreeGroup) baseRing).setRootVal(sym,val);
return false;
}
/** Returns an approximation to the value of the root as a complex number. */
public Complex getRootVal() {
return rootVal;
}
/** Returns the symbol used to denote the generator. */
public String getSymbol() {
return symbol;
}
/** Whether the given polynomial is constant. */
public boolean isConstantPoly(Number poly) {
return ((FreeGroupElement) poly).isConstantPoly();
}
}