public void MultiplyBigDecimal()
{
BigDecimal multi1 = new BigDecimal(value, 5);
BigDecimal multi2 = new BigDecimal(2.345D);
BigDecimal result = BigMath.Multiply(multi1, multi2);
Assert.True(result.ToString().StartsWith("289.51154260") && result.Scale == multi1.Scale + multi2.Scale,
"123.45908 * 2.345 is not correct: " + result);
multi1 = BigDecimal.Parse("34656");
multi2 = BigDecimal.Parse("-2");
result = BigMath.Multiply(multi1, multi2);
Assert.True(result.ToString().Equals("-69312") && result.Scale == 0, "34656 * 2 is not correct");
multi1 = new BigDecimal(-2.345E-02);
multi2 = new BigDecimal(-134E130);
result = BigMath.Multiply(multi1, multi2);
Assert.True(result.ToDouble() == 3.1422999999999997E130 && result.Scale == multi1.Scale + multi2.Scale,
"-2.345E-02 * -134E130 is not correct " + result.ToDouble());
multi1 = BigDecimal.Parse("11235");
multi2 = BigDecimal.Parse("0");
result = BigMath.Multiply(multi1, multi2);
Assert.True(result.ToDouble() == 0 && result.Scale == 0, "11235 * 0 is not correct");
multi1 = BigDecimal.Parse("-0.00234");
multi2 = new BigDecimal(13.4E10);
result = BigMath.Multiply(multi1, multi2);
Assert.True(result.ToDouble() == -313560000 && result.Scale == multi1.Scale + multi2.Scale,
"-0.00234 * 13.4E10 is not correct");
}
public static BigDecimal Pow(BigDecimal number, int n, MathContext mc)
{
// The ANSI standard X3.274-1996 algorithm
int m = System.Math.Abs(n);
int mcPrecision = mc.Precision;
int elength = (int)System.Math.Log10(m) + 1; // decimal digits in 'n'
int oneBitMask; // mask of bits
BigDecimal accum; // the single accumulator
MathContext newPrecision = mc; // MathContext by default
// In particular cases, it reduces the problem to call the other 'pow()'
if ((n == 0) || ((number.IsZero) && (n > 0)))
{
return(Pow(number, n));
}
if ((m > 999999999) || ((mcPrecision == 0) && (n < 0)) ||
((mcPrecision > 0) && (elength > mcPrecision)))
{
// math.07=Invalid Operation
throw new ArithmeticException(Messages.math07); //$NON-NLS-1$
}
if (mcPrecision > 0)
{
newPrecision = new MathContext(mcPrecision + elength + 1,
mc.RoundingMode);
}
// The result is calculated as if 'n' were positive
accum = BigMath.Round(number, newPrecision);
oneBitMask = Utils.HighestOneBit(m) >> 1;
while (oneBitMask > 0)
{
accum = BigMath.Multiply(accum, accum, newPrecision);
if ((m & oneBitMask) == oneBitMask)
{
accum = BigMath.Multiply(accum, number, newPrecision);
}
oneBitMask >>= 1;
}
// If 'n' is negative, the value is divided into 'ONE'
if (n < 0)
{
accum = Divide(BigDecimal.One, accum, newPrecision);
}
// The final value is rounded to the destination precision
accum.InplaceRound(mc);
return(accum);
}
public static BigInteger operator *(BigInteger a, BigInteger b)
{
return(BigMath.Multiply(a, b));
}
