本文整理汇总了C#中Rational.Multiply方法的典型用法代码示例。如果您正苦于以下问题：C# Rational.Multiply方法的具体用法？C# Rational.Multiply怎么用？C# Rational.Multiply使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类Rational的用法示例。
在下文中一共展示了Rational.Multiply方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C#代码示例。
示例1: Log
public static BigDecimal Log(int n, MathContext mc)
{
/* the value is undefined if x is negative.
*/
if (n <= 0)
throw new ArithmeticException("Cannot take log of negative " + n);
if (n == 1)
return BigDecimal.Zero;
if (n == 2) {
if (mc.Precision < Log2.Precision)
return Log2.Round(mc);
/* Broadhurst <a href="http://arxiv.org/abs/math/9803067">arXiv:math/9803067</a>
* Error propagation: the error in log(2) is twice the error in S(2,-5,...).
*/
int[] a = {2, -5, -2, -7, -2, -5, 2, -3};
BigDecimal S = BroadhurstBbp(2, 1, a, new MathContext(1 + mc.Precision));
S = S.Multiply(new BigDecimal(8));
S = Sqrt(DivideRound(S, 3));
return S.Round(mc);
}
if (n == 3) {
/* summation of a series roughly proportional to (7/500)^k. Estimate count
* of terms to estimate the precision (drop the favorable additional
* 1/k here): 0.013^k <= 10^(-precision), so k*log10(0.013) <= -precision
* so k>= precision/1.87.
*/
var kmax = (int) (mc.Precision/1.87);
var mcloc = new MathContext(mc.Precision + 1 + (int) (System.Math.Log10(kmax*0.693/1.098)));
BigDecimal log3 = MultiplyRound(Log(2, mcloc), 19);
/* log3 is roughly 1, so absolute and relative error are the same. The
* result will be divided by 12, so a conservative error is the one
* already found in mc
*/
double eps = PrecisionToError(1.098, mc.Precision)/kmax;
var r = new Rational(7153, 524288);
var pk = new Rational(7153, 524288);
for (int k = 1;; k++) {
Rational tmp = pk.Divide(k);
if (tmp.ToDouble() < eps)
break;
/* how many digits of tmp do we need in the sum?
*/
mcloc = new MathContext(ErrorToPrecision(tmp.ToDouble(), eps));
BigDecimal c = pk.Divide(k).ToBigDecimal(mcloc);
if (k%2 != 0)
log3 = log3.Add(c);
else
log3 = log3.Subtract(c);
pk = pk.Multiply(r);
}
log3 = DivideRound(log3, 12);
return log3.Round(mc);
}
if (n == 5) {
/* summation of a series roughly proportional to (7/160)^k. Estimate count
* of terms to estimate the precision (drop the favorable additional
* 1/k here): 0.046^k <= 10^(-precision), so k*log10(0.046) <= -precision
* so k>= precision/1.33.
*/
var kmax = (int) (mc.Precision/1.33);
var mcloc = new MathContext(mc.Precision + 1 + (int) (System.Math.Log10(kmax*0.693/1.609)));
BigDecimal log5 = MultiplyRound(Log(2, mcloc), 14);
/* log5 is roughly 1.6, so absolute and relative error are the same. The
* result will be divided by 6, so a conservative error is the one
* already found in mc
*/
double eps = PrecisionToError(1.6, mc.Precision)/kmax;
var r = new Rational(759, 16384);
var pk = new Rational(759, 16384);
for (int k = 1;; k++) {
Rational tmp = pk.Divide(k);
if (tmp.ToDouble() < eps)
break;
/* how many digits of tmp do we need in the sum?
*/
mcloc = new MathContext(ErrorToPrecision(tmp.ToDouble(), eps));
BigDecimal c = pk.Divide(k).ToBigDecimal(mcloc);
log5 = log5.Subtract(c);
pk = pk.Multiply(r);
}
log5 = DivideRound(log5, 6);
return log5.Round(mc);
}
if (n == 7) {
/* summation of a series roughly proportional to (1/8)^k. Estimate count
* of terms to estimate the precision (drop the favorable additional
* 1/k here): 0.125^k <= 10^(-precision), so k*log10(0.125) <= -precision
* so k>= precision/0.903.
*/
var kmax = (int) (mc.Precision/0.903);
var mcloc = new MathContext(mc.Precision + 1 + (int) (System.Math.Log10(kmax*3*0.693/1.098)));
BigDecimal log7 = MultiplyRound(Log(2, mcloc), 3);
/* log7 is roughly 1.9, so absolute and relative error are the same.
*/
double eps = PrecisionToError(1.9, mc.Precision)/kmax;
//.........这里部分代码省略.........