void agm(mpf_class& rop1, mpf_class& rop2, const mpf_class& op1,
const mpf_class& op2)
{
rop1 = (op1 + op2) / 2;
rop2 = op1 * op2;
mpf_sqrt(rop2.get_mpf_t(), rop2.get_mpf_t());
}
bool _Format_f(Signal &sig, Formatter *pFormatter,
const Formatter::Flags &flags, const mpf_class &num)
{
char *str = nullptr;
::gmp_asprintf(&str, Formatter::ComposeFlags(flags, "Ff").c_str(), num.get_mpf_t());
bool rtn = pFormatter->PutString(sig, str);
::free(str);
return rtn;
}
//
// The core Gauss - Legendre routine.
// On input, 'bits' is the desired precision in bits.
// On output, 'pi' contains the calculated value.
//
static void calculatePi( unsigned bits, mpf_class & pi )
{
mpf_class lastPi( 0.0 );
mpf_class scratch;
// variables per the formal Gauss - Legendre formulae
mpf_class a;
mpf_class b;
mpf_class t;
mpf_class x;
mpf_class y;
unsigned p = 1;
// initial conditions
a = 1;
// b := 1 / sqrt( 2 )
mpf_sqrt_ui( b.get_mpf_t( ), 2 );
b = 1.0 / b;
t = 0.25;
for( ;; ) {
x = ( a + b )/2;
// y := sqrt( ab )
y = a * b;
mpf_sqrt( y.get_mpf_t( ), y.get_mpf_t( ) );
// t := t - p * ( a - x )**2
scratch = a - x;
scratch *= scratch;
scratch *= p;
t -= scratch;
a = x;
b = y;
p <<= 1;
// pi := ( ( a + b )**2 ) / 4t
pi = a + b;
pi *= pi;
pi /= ( 4 * t );
// if pi == lastPi, within the requested precision, we're done
if ( mpf_eq( pi.get_mpf_t( ), lastPi.get_mpf_t( ), bits ) ) {
break;
}
lastPi = pi;
}
}
std::string fixTrailingZeros(mpf_class &num, int precision) {
char *buffer = NULL;
gmp_asprintf(&buffer, "%.*Ff", precision + 2, num.get_mpf_t());
int counter = strlen(buffer) - 2;
buffer[counter] = '\0';
--counter;
while (buffer[counter] == '0') {
buffer[counter] = '\0';
--counter;
}
if (buffer[counter] == '.') {
buffer[counter] = '\0';
}
return std::string(buffer);
}
/*
* Evaluate the series 1/0! + 1/1! + 1/2! + 1/3! + 1/4! ...
* On input, 'bits' is the desired precision in bits.
* On output, e' contains the calculated value.
*/
static void calculateE(
unsigned bits,
mpf_class &e)
{
/* initial conditions, including the first two terms */
mpf_class lastE(0.0);
mpf_class invFact(1.0); /* 1/2!, 1/3!, 1/4!, etc. */
unsigned term = 2; /* 2, 3, 4... */
e = 2;
for(;;) {
invFact /= term;
e += invFact;
/* if e == lastE, within the requested precision, we're done */
if(mpf_eq(e.get_mpf_t(), lastE.get_mpf_t(), bits)) {
return;
}
lastE = e;
term++;
}
/* NOT REACHED */
}
QDebug operator<<(QDebug s, const mpf_class& m) {
char b[65536] = "";
gmp_sprintf (b, "%.9Ff", m.get_mpf_t());
s << b;
return s;
}
