GF256Poly[] divide(GF256Poly other) { if (!field.equals(other.field)) { throw new IllegalArgumentException("GF256Polys do not have same GF256 field"); } if (other.isZero()) { throw new IllegalArgumentException("Divide by 0"); } GF256Poly quotient = field.getZero(); GF256Poly remainder = this; int denominatorLeadingTerm = other.getCoefficient(other.getDegree()); int inverseDenominatorLeadingTerm = field.inverse(denominatorLeadingTerm); while (remainder.getDegree() >= other.getDegree() && !remainder.isZero()) { int degreeDifference = remainder.getDegree() - other.getDegree(); int scale = field.multiply(remainder.getCoefficient(remainder.getDegree()), inverseDenominatorLeadingTerm); GF256Poly term = other.multiplyByMonomial(degreeDifference, scale); GF256Poly iterationQuotient = field.buildMonomial(degreeDifference, scale); quotient = quotient.addOrSubtract(iterationQuotient); remainder = remainder.addOrSubtract(term); } return new GF256Poly[] { quotient, remainder }; }
GF256Poly[] divide(GF256Poly other) { if (!field.equals(other.field)) { throw new IllegalArgumentException("GF256Polys do not have same GF256 field"); } if (other.isZero()) { throw new IllegalArgumentException("Divide by 0"); } GF256Poly quotient = field.getZero(); GF256Poly remainder = this; int denominatorLeadingTerm = other.getCoefficient(other.getDegree()); int inverseDenominatorLeadingTerm = field.inverse(denominatorLeadingTerm); while (remainder.getDegree() >= other.getDegree() && !remainder.isZero()) { int degreeDifference = remainder.getDegree() - other.getDegree(); int scale = field.multiply(remainder.getCoefficient(remainder.getDegree()), inverseDenominatorLeadingTerm); GF256Poly term = other.multiplyByMonomial(degreeDifference, scale); GF256Poly iterationQuotient = field.buildMonomial(degreeDifference, scale); quotient = quotient.addOrSubtract(iterationQuotient); remainder = remainder.addOrSubtract(term); } return new GF256Poly[] { quotient, remainder }; }
int degreeDiff = r.getDegree() - rLast.getDegree(); int scale = field.multiply(r.getCoefficient(r.getDegree()), dltInverse); q = q.addOrSubtract(field.buildMonomial(degreeDiff, scale)); r = r.addOrSubtract(rLast.multiplyByMonomial(degreeDiff, scale)); s = q.multiply(sLast).addOrSubtract(sLastLast); t = q.multiply(tLast).addOrSubtract(tLastLast);