void conv(quad_float& z, const RR& a)
{
long old_p;
static RR a_hi, a_lo;
old_p = RR::prec;
ConvPrec(a_hi, a, NTL_DOUBLE_PRECISION); // high order bits
SubPrec(a_lo, a, a_hi, NTL_DOUBLE_PRECISION); // low order bits
z = to_quad_float(a_hi.x)*power2_quad_float(a_hi.e) +
to_quad_float(a_lo.x)*power2_quad_float(a_lo.e);
}
quad_float exp(const quad_float& x) { // New version 97 Aug 05
/*
! Calculate a quadruple-precision exponential
! Method:
! x x.log2(e) nint[x.log2(e)] + frac[x.log2(e)]
! e = 2 = 2
!
! iy fy
! = 2 . 2
! Then
! fy y.loge(2)
! 2 = e
!
! Now y.loge(2) will be less than 0.3466 in absolute value.
! This is halved and a Pade aproximation is used to approximate e^x over
! the region (-0.1733, +0.1733). This approximation is then squared.
*/
if (x.hi<DBL_MIN_10_EXP*2.302585092994045684017991)
return to_quad_float(0.0);
if (x.hi>DBL_MAX_10_EXP*2.302585092994045684017991) {
Error("exp(quad_float): overflow");
}
// changed this from "const" to "static" in v5.3, since "const"
// causes the initialization to be performed with *every* invocation.
static quad_float Log2 =
to_quad_float("0.6931471805599453094172321214581765680755");
quad_float y,temp,ysq,sum1,sum2;
long iy;
y=x/Log2;
temp = floor(y+0.5);
iy = to_long(temp);
y=(y-temp)*Log2;
y=ldexp(y,-1L);
ysq=y*y;
sum1=y*((((ysq+3960.0)*ysq+2162160.0)*ysq+302702400.0)*ysq+8821612800.0);
sum2=(((90.0*ysq+110880.0)*ysq+30270240.0)*ysq+2075673600.0)*ysq+17643225600.0;
/*
! sum2 + sum1 2.sum1
! Now approximation = ----------- = 1 + ----------- = 1 + 2.temp
! sum2 - sum1 sum2 - sum1
!
! Then (1 + 2.temp)^2 = 4.temp.(1 + temp) + 1
*/
temp=sum1/(sum2-sum1);
y=temp*(temp+1);
y=ldexp(y,2L);
return ldexp(y+1,iy);
}
NTL_CLIENT
int main()
{
quad_float a, b, c, d;
quad_float::SetOutputPrecision(25);
if (PrecisionOK())
cout << "Precision OK\n";
else
cout << "Precision not OK\n";
cin >> a;
cout << a << "\n";
cin >> b;
cout << b << "\n";
c = a + b;
d = a;
d += b;
cout << c << "\n";
cout << d << "\n";
c = a - b;
d = a;
d -= b;
cout << c << "\n";
cout << d << "\n";
c = a * b;
d = a;
d *= b;
cout << c << "\n";
cout << d << "\n";
c = a / b;
d = a;
d /= b;
cout << c << "\n";
cout << d << "\n";
c = -a;
cout << c << "\n";
c = sqrt(a);
cout << c << "\n";
power(c, to_quad_float(10), 20);
cout << c << "\n";
{
long n, n1;
int shamt = min(NTL_BITS_PER_LONG,2*NTL_DOUBLE_PRECISION);
n = to_long((1UL << (shamt-1)) - 1UL);
c = to_quad_float(n);
n1 = to_long(c);
if (n1 == n)
cout << "long conversion OK\n";
else
cout << "long conversion not OK\n";
n = to_long(1UL << (shamt-1));
c = to_quad_float(n);
n1 = to_long(c);
if (n1 == n)
cout << "long conversion OK\n";
else
cout << "long conversion not OK\n";
}
{
unsigned long n;
ZZ n1;
int shamt = min(NTL_BITS_PER_LONG,2*NTL_DOUBLE_PRECISION);
n = (1UL << (shamt-1)) - 1UL;
c = to_quad_float(n);
n1 = to_ZZ(c);
if (n1 == to_ZZ(n))
cout << "ulong conversion OK\n";
else
cout << "ulong conversion not OK\n";
n = 1UL << (shamt-1);
c = to_quad_float(n);
n1 = to_ZZ(c);
if (n1 == to_ZZ(n))
cout << "ulong conversion OK\n";
else
cout << "ulong conversion not OK\n";
}
}
