public static Fp Mul(Fp a, Fp b)
{
double[] r = new double[POS_COUNT * 2];
double carry = 0;
int ri;
for (int ai = POS_COUNT - 1; ai >= 0; ai--)
{
ri = ai + POS_COUNT;
for (int bi = POS_COUNT - 1; bi >= 0; bi--)
{
//string lh = a.GetDigitBin(ai);
//string rh = b.GetDigitBin(bi);
double p = r[ri] + carry + a._digs[ai] * b._digs[bi];
carry = BreakUp(p, BASE, out double remain);
r[ri] = remain;
ri--;
}
}
//r[0] = carry;
if (carry != 0)
{
throw new OverflowException("Multiplication has caused an overflow.");
}
//DMathUtil.ReportDigitsBin(a.GetDouble(), r);
int cl = POS_COUNT;
//int cl = POS_COUNT * 2 - 1;
//cl = 2;
double[] rr = new double[cl];
for (int i = 0; i < cl; i++)
{
rr[i] = r[i + 1];
}
Fp tResult = new Fp(rr);
if (r[POS_COUNT + 1] > HALF_BASE)
{
//rr[POS_COUNT - 1] += Math.Pow(2, (POS_COUNT - 1) * -STEP);
//Fp result = Add(tResult, new Fp(Math.Pow(2, (POS_COUNT - 1) * -STEP)));
//return result;
return(tResult);
}
else
{
return(tResult);
}
}
public static Fp Add(Fp a, int b)
{
double carry = BreakUp(a._digs[0] + b, BASE, out double remain);
if (carry != 0)
{
throw new OverflowException("Addition (with integer) has resulted in an overflow.");
}
Fp result = new Fp(a);
result._digs[0] += b;
return(result);
}
// LSB * each of b
//a2 * b2 -> r5;
//a2 * b1 -> r4;
//a2 * b0 -> r3;
//a1 * b2 -> r4;
//a1 * b1 -> r5;
//a1 * b0 -> r2;
// HSB * each of b
//a0 * b2 -> r3;
//a0 * b1 -> r2;
//a0 * b0 -> r1;
// multiply(a[1..p], b[1..q], base) // Operands containing rightmost digits at index 1
// product = [1..p+q] // Allocate space for result
// for b_i = 1 to q // for all digits in b
//carry = 0
// for a_i = 1 to p // for all digits in a
// product[a_i + b_i - 1] += carry + a[a_i] * b[b_i]
// carry = product[a_i + b_i - 1] / base
// product[a_i + b_i - 1] = product[a_i + b_i - 1] mod base
//product[b_i + p] = carry // last digit comes from final carry
// return product
public static Fp Add(Fp a, Fp b)
{
double[] r = new double[POS_COUNT];
double carry = 0;
for (int i = POS_COUNT - 1; i >= 0; i--)
{
double s = carry + a._digs[i] + b._digs[i];
carry = BreakUp(s, BASE, out double remain);
r[i] = remain;
}
if (carry != 0)
{
throw new OverflowException("Addition has resulted in an overflow.");
}
return(new Fp(r));
}
public Fp(Fp x) : this(x._digs)
{
}