public equation CombineAndReduce(equation othereq)
{
long topmultiplier = 0, bottommultiplier = 0;
// This function considers "this" the top, and othereq the bottom.
// It multiplies both equations by the first coefficient of the opposite equation,
// and then subtracts the bottom from the top, eliminating the first coefficient from
// the left side, and adding coefficients to the right.
equation neweq = new equation();
othereq.KillFactors();
for (int i = 0; i < leftside.Count; i++)
{
coefficient topco = leftside[i];
coefficient bottomco = othereq.leftside[i];
if (i == 0)
{
topmultiplier = bottomco.multiplier;
bottommultiplier = topco.multiplier;
// avoid saving a coefficient because the multiplier and subtraction guarantee they cancel
}
else
{
neweq.leftside.Add(new coefficient(topco.multiplier * topmultiplier - bottomco.multiplier * bottommultiplier, topco.vindex));
}
}
for (int i = 0; i < 8; i++)
{
long multiplier = 0;
foreach (coefficient r in rightside)
{
if (r.vindex == i)
{
multiplier += (r.multiplier * topmultiplier);
}
}
foreach (coefficient r in othereq.rightside)
{
if (r.vindex == i)
{
multiplier -= (r.multiplier * bottommultiplier);
}
}
if (multiplier != 0)
{
neweq.rightside.Add(new coefficient(multiplier, i));
}
}
neweq.KillFactors();
return(neweq);
}
public void SolveLeft(BigInteger[] v)
{
for (int i = 0; i < 8; i++)
{
if (v[i] != null && v[i].Equals(BigInteger.Zero) == false)
{
// find anything on the left that uses this value and eliminate it.
for (int j = 0; j < leftside.Count; j++)
{
coefficient c = leftside[j];
if (c.vindex == i)
{
// found something - eliminate it
BigInteger accum = v[i];
accum = accum.Multiply(new BigInteger(c.multiplier.ToString()));
// now subtract the whole thing from both sides
subtractor = subtractor.Add(accum);
leftside.RemoveAt(j);
j--;
}
}
}
}
}
