本文整理汇总了C++中BigInteger::lshift方法的典型用法代码示例。如果您正苦于以下问题：C++ BigInteger::lshift方法的具体用法？C++ BigInteger::lshift怎么用？C++ BigInteger::lshift使用的例子？那么, 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BigInteger的用法示例。
在下文中一共展示了BigInteger::lshift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: not
/* Was hoping dividing via a Newton's approximation of the reciprocal would be faster, but
its not (makes D2A about twice as slow!). Its not the 32bit divide above that's slow,
its how many times you have to iterate over entire BigIntegers. Below uses a shift,
and three multiplies:
*/
BigInteger* BigInteger::divideByReciprocalMethod(const BigInteger* divisor, BigInteger* residual, BigInteger* result)
{
// handle easy cases where divisor is >= this
int compareTo = this->compare(divisor);
if (compareTo == -1)
{
residual->copyFrom(this);
result->setValue(0);
return result;
}
else if (compareTo == 0)
{
residual->setValue(0);
result->setValue(1);
return result;
}
uint32 d2Prec = divisor->lg2();
uint32 e = 1 + d2Prec;
uint32 ag = 1;
uint32 ar = 31 + this->lg2() - d2Prec;
BigInteger u;
u.setFromInteger(1);
BigInteger ush;
ush.setFromInteger(1);
BigInteger usq;
usq.setFromInteger(0);
while (1)
{
u.lshift(e + 1,&ush);
divisor->mult(&u,&usq); // usq = divisor*u^2
usq.multBy(&u);
ush.subtract(&usq, &u); // u = ush - usq;
int32 ush2 = u.lg2(); // ilg2(u);
e *= 2;
ag *= 2;
int32 usq2 = 4 + ag;
ush2 -= usq2; // BigInteger* diff = ush->subtract(usq); // ush -= usq; ush > 0
if (ush2 > 0) // (ush->compare(usq) == 1)
{
u.rshiftBy(ush2); // u >>= ush;
e -= ush2;
}
if (ag > ar)
break;
}
result = this->mult(&u,result); // mult by reciprocal (scaled by e)
result->rshiftBy(e); // remove scaling
BigInteger temp;
temp.setFromInteger(0);
divisor->mult(result, &temp); // compute residual as this - divisor*result
this->subtract(&temp,residual); // todo: should be a more optimal way of doing this
// ... doesn't work, e is the wrong scale for this (too large)....
// residual = this->lshift(e,residual); // residual = (this*2^e - result) / 2^e
// residual->decrementBy(result);
// residual->rshiftBy(e); // remove scaling
return(result);
}