public static BigFloat Multiply(BigFloat a, BigFloat b)
{
a = (BigFloat)a.Clone();
b = (BigFloat)b.Clone();
if (b.Length > a.Length) // then switch them around
{
BigFloat temp = a;
a = b;
b = temp;
}
BigFloat retval = new BigFloat();
List <BigFloat> rows = new List <BigFloat>();
retval._sign = a.Sign == b.Sign;
retval._exp = a._exp + b._exp;
// for each digit in b
for (int i = 0; i < b.Length; i++)
{
BigFloat row = new BigFloat();
row._exp = retval._exp;
Int32 digit = 0, carry = 0;
for (int exp = 0; exp < i; exp++)
{
row._data.Add(0); // pad with zeros to the right
}
for (int j = 0; j < a.Length; j++) // perform per-digit multiplication of a against b
{
digit = a[j] * b[i] + carry;
carry = digit / 10;
digit = digit % 10;
row._data.Add((SByte)digit);
}
// reduce the carry
while (carry > 0)
{
digit = carry % 10;
carry = carry / 10;
row._data.Add((SByte)digit);
}
rows.Add(row);
}
// sum the rows to give the result
foreach (BigFloat row in rows)
{
retval = (BigFloat)retval.Add(row);
}
retval.Normalise();
return(retval);
}
public static BigFloat Divide(BigFloat dividend, BigFloat divisor, out Boolean isExact)
{
if (divisor.IsZero)
{
throw new DivideByZeroException();
}
isExact = true;
if (dividend.IsZero)
{
return((BigFloat)dividend.Clone());
}
///////////////////////////////
BigFloat quotient = new BigFloat();
quotient._sign = dividend.Sign == divisor.Sign;
dividend = (BigFloat)dividend.Absolute();
divisor = (BigFloat)divisor.Absolute();
BigFloat aPortion;
BigFloat bDigit = null;
//////////////////////////////
while (divisor[0] == 0) // remove least-significant zeros and up the exponent to compensate
{
divisor._exp++;
divisor._data.RemoveAt(0);
}
quotient._exp = dividend.Length + dividend._exp - divisor.Length - divisor._exp + 1;
dividend._exp = 0;
divisor._exp = 0;
aPortion = new BigFloat();
Int32 bump = 0, c = -1;
Boolean hump = false;
isExact = false;
while (quotient.Length < _divisionDigits) // abandon hope all ye who enter here
{
aPortion = dividend.Msd(divisor.Length + (hump ? 1 : 0));
if (aPortion < divisor)
{
int i = 1;
while (aPortion < divisor)
{
aPortion = dividend.Msd(divisor.Length + i + (hump ? 1 : 0));
quotient._exp--;
quotient._data.Add(0);
i++;
}
hump = true;
}
bDigit = 0; //tt = 0;
c = 0;
while (bDigit < aPortion)
{
bDigit = (BigFloat)bDigit.Add(divisor); //tt += b;
c++;
}
if (bDigit != aPortion)
{
c--;
bDigit = new BigFloat(c);
bDigit = (BigFloat)bDigit.Multiply(divisor); //tt *= b;
isExact = false;
}
else
{
isExact = true;
}
quotient._data.Add((sbyte)c);
quotient._exp--;
aPortion.Normalise();
dividend.Normalise();
bump = aPortion.Length - bDigit.Length;
if (aPortion.Length > dividend.Length)
{
dividend = aPortion;
}
bDigit = bDigit.Msd(dividend.Length - bump);
aPortion = BigFloat.Add(dividend, (BigFloat)bDigit.Negate(), false);
dividend = (BigFloat)aPortion.Clone();
if (aPortion.IsZero)
{
break; // no more work necessary
}
if (hump)
{
if (dividend[dividend.Length - 1] == 0)
{
dividend._data.RemoveAt(dividend.Length - 1);
}
}
if (dividend[dividend.Length - 1] == 0)
{
dividend._data.RemoveAt(dividend.Length - 1);
while (dividend[dividend.Length - 1] == 0)
{
quotient._exp--;
quotient._data.Add(0);
dividend._data.RemoveAt(dividend.Length - 1);
if (dividend.Length == 0)
{
break;
}
}
if (dividend.Length == 0)
{
break;
}
hump = false;
}
else
{
hump = true;
}
if (quotient.Length == 82)
{
c = 0;
}
}
quotient._data.Reverse();
quotient.Normalise();
return(quotient);
}
protected override BigNum Add(BigNum other)
{
return(BigFloat.Add(this, (BigFloat)other));
}
public static BigFloat Multiply(BigFloat a, BigFloat b)
{
a = (BigFloat)a.Clone();
b = (BigFloat)b.Clone();
if(b.Length > a.Length) { // then switch them around
BigFloat temp = a;
a = b;
b = temp;
}
BigFloat retval = new BigFloat();
List<BigFloat> rows = new List<BigFloat>();
retval._sign = a.Sign == b.Sign;
retval._exp = a._exp + b._exp;
// for each digit in b
for(int i=0;i<b.Length;i++) {
BigFloat row = new BigFloat();
row._exp = retval._exp;
Int32 digit = 0, carry = 0;
for(int exp=0;exp<i;exp++) row._data.Add( 0 ); // pad with zeros to the right
for(int j=0;j<a.Length;j++) { // perform per-digit multiplication of a against b
digit = a[j] * b[i] + carry;
carry = digit / 10;
digit = digit % 10;
row._data.Add( (SByte)digit );
}
// reduce the carry
while(carry > 0) {
digit = carry % 10;
carry = carry / 10;
row._data.Add( (SByte)digit );
}
rows.Add( row );
}
// sum the rows to give the result
foreach(BigFloat row in rows) {
retval = (BigFloat)retval.Add(row);
}
retval.Normalise();
return retval;
}