ArrayPolynomialModular.java

package jscl.math.polynomial;

import jscl.math.Generic;
import jscl.math.JsclInteger;
import jscl.math.ModularInteger;

import javax.annotation.Nonnull;

class ArrayPolynomialModular extends ArrayPolynomialGeneric {
    final int modulo;
    int coef[];

    ArrayPolynomialModular(Monomial monomialFactory, Generic coefFactory) {
        super(monomialFactory, coefFactory);
        modulo = ((ModularInteger) coefFactory).modulo();
    }

    ArrayPolynomialModular(int size, Monomial monomialFactory, Generic coefFactory) {
        this(monomialFactory, coefFactory);
        init(size);
    }

    void init(int size) {
        monomial = new Monomial[size];
        coef = new int[size];
        this.size = size;
    }

    void resize(int size) {
        int length = monomial.length;
        if (size < length) {
            Monomial monomial[] = new Monomial[size];
            int coef[] = new int[size];
            System.arraycopy(this.monomial, length - size, monomial, 0, size);
            System.arraycopy(this.coef, length - size, coef, 0, size);
            this.monomial = monomial;
            this.coef = coef;
            this.size = size;
        }
    }

    @Nonnull
    public Polynomial subtract(@Nonnull Polynomial that) {
        if (that.signum() == 0) return this;
        ArrayPolynomialModular q = (ArrayPolynomialModular) that;
        ArrayPolynomialModular p = (ArrayPolynomialModular) newinstance(size + q.size);
        int i = p.size;
        int i1 = size;
        int i2 = q.size;
        Monomial m1 = i1 > 0 ? monomial[--i1] : null;
        Monomial m2 = i2 > 0 ? q.monomial[--i2] : null;
        while (m1 != null || m2 != null) {
            int c = m1 == null ? 1 : (m2 == null ? -1 : -ordering.compare(m1, m2));
            if (c < 0) {
                int a = coef[i1];
                --i;
                p.monomial[i] = m1;
                p.coef[i] = a;
                m1 = i1 > 0 ? monomial[--i1] : null;
            } else if (c > 0) {
                int a = (int) (((long) modulo - (long) q.coef[i2]) % modulo);
                --i;
                p.monomial[i] = m2;
                p.coef[i] = a;
                m2 = i2 > 0 ? q.monomial[--i2] : null;
            } else {
                int a = (int) (((long) coef[i1] + (long) modulo - (long) q.coef[i2]) % modulo);
                if (a != 0) {
                    --i;
                    p.monomial[i] = m1;
                    p.coef[i] = a;
                }
                m1 = i1 > 0 ? monomial[--i1] : null;
                m2 = i2 > 0 ? q.monomial[--i2] : null;
            }
        }
        p.resize(p.size - i);
        p.degree = degree(p);
        p.sugar = Math.max(sugar, q.sugar);
        return p;
    }

    public Polynomial multiplyAndSubtract(Generic generic, Polynomial polynomial) {
        if (generic.signum() == 0) return this;
        int g = generic.integerValue().intValue();
        if (g == 1) return subtract(polynomial);
        ArrayPolynomialModular q = (ArrayPolynomialModular) polynomial;
        ArrayPolynomialModular p = (ArrayPolynomialModular) newinstance(size + q.size);
        int i = p.size;
        int i1 = size;
        int i2 = q.size;
        Monomial m1 = i1 > 0 ? monomial[--i1] : null;
        Monomial m2 = i2 > 0 ? q.monomial[--i2] : null;
        while (m1 != null || m2 != null) {
            int c = m1 == null ? 1 : (m2 == null ? -1 : -ordering.compare(m1, m2));
            if (c < 0) {
                int a = coef[i1];
                --i;
                p.monomial[i] = m1;
                p.coef[i] = a;
                m1 = i1 > 0 ? monomial[--i1] : null;
            } else if (c > 0) {
                int a = (int) (((long) modulo - ((long) q.coef[i2] * (long) g) % modulo) % modulo);
                --i;
                p.monomial[i] = m2;
                p.coef[i] = a;
                m2 = i2 > 0 ? q.monomial[--i2] : null;
            } else {
                int a = (int) (((long) coef[i1] + (long) modulo - ((long) q.coef[i2] * (long) g) % modulo) % modulo);
                if (a != 0) {
                    --i;
                    p.monomial[i] = m1;
                    p.coef[i] = a;
                }
                m1 = i1 > 0 ? monomial[--i1] : null;
                m2 = i2 > 0 ? q.monomial[--i2] : null;
            }
        }
        p.resize(p.size - i);
        p.degree = degree(p);
        p.sugar = Math.max(sugar, q.sugar);
        return p;
    }

    public Polynomial multiplyAndSubtract(Monomial monomial, Generic generic, Polynomial polynomial) {
        if (defined) throw new UnsupportedOperationException();
        if (generic.signum() == 0) return this;
        if (monomial.degree() == 0) return multiplyAndSubtract(generic, polynomial);
        int g = generic.integerValue().intValue();
        ArrayPolynomialModular q = (ArrayPolynomialModular) polynomial;
        ArrayPolynomialModular p = (ArrayPolynomialModular) newinstance(size + q.size);
        int i = p.size;
        int i1 = size;
        int i2 = q.size;
        Monomial m1 = i1 > 0 ? this.monomial[--i1] : null;
        Monomial m2 = i2 > 0 ? q.monomial[--i2].multiply(monomial) : null;
        while (m1 != null || m2 != null) {
            int c = m1 == null ? 1 : (m2 == null ? -1 : -ordering.compare(m1, m2));
            if (c < 0) {
                int a = coef[i1];
                --i;
                p.monomial[i] = m1;
                p.coef[i] = a;
                m1 = i1 > 0 ? this.monomial[--i1] : null;
            } else if (c > 0) {
                int a = (int) (((long) modulo - ((long) q.coef[i2] * (long) g) % modulo) % modulo);
                --i;
                p.monomial[i] = m2;
                p.coef[i] = a;
                m2 = i2 > 0 ? q.monomial[--i2].multiply(monomial) : null;
            } else {
                int a = (int) (((long) coef[i1] + (long) modulo - ((long) q.coef[i2] * (long) g) % modulo) % modulo);
                if (a != 0) {
                    --i;
                    p.monomial[i] = m1;
                    p.coef[i] = a;
                }
                m1 = i1 > 0 ? this.monomial[--i1] : null;
                m2 = i2 > 0 ? q.monomial[--i2].multiply(monomial) : null;
            }
        }
        p.resize(p.size - i);
        p.degree = degree(p);
        p.sugar = Math.max(sugar, q.sugar + monomial.degree());
        return p;
    }

    public Polynomial multiply(Generic generic) {
        if (generic.signum() == 0) return valueOf(JsclInteger.valueOf(0));
        int g = generic.integerValue().intValue();
        if (g == 1) return this;
        ArrayPolynomialModular p = (ArrayPolynomialModular) newinstance(size);
        for (int i = 0; i < size; i++) {
            p.monomial[i] = monomial[i];
            p.coef[i] = (int) (((long) coef[i] * (long) g) % modulo);
        }
        p.degree = degree;
        p.sugar = sugar;
        return p;
    }

    public Polynomial multiply(Monomial monomial) {
        if (defined) throw new UnsupportedOperationException();
        if (monomial.degree() == 0) return this;
        ArrayPolynomialModular p = (ArrayPolynomialModular) newinstance(size);
        for (int i = 0; i < size; i++) {
            p.monomial[i] = this.monomial[i].multiply(monomial);
            p.coef[i] = coef[i];
        }
        p.degree = degree + monomial.degree();
        p.sugar = sugar + monomial.degree();
        return p;
    }

    protected Generic coefficient(Generic generic) {
        return coefFactory.valueOf(generic);
    }

    protected Generic getCoef(int n) {
        return new ModularInteger(coef[n], modulo);
    }

    protected void setCoef(int n, Generic generic) {
        coef[n] = generic.integerValue().intValue();
    }

    protected ArrayPolynomialGeneric newinstance(int n) {
        return new ArrayPolynomialModular(n, monomialFactory, coefFactory);
    }
}