/*  sdfexbsr.cpp  by K.Tsuru  */
/***********************************************************************
It evaluates exp(n/d) with ExpBSRType n and d using binary splitting method.
************************************************************************/

#ifndef SN_H
#include "sn.h"
#endif

static const char* const func = "ExpBSR()";
typedef SLong ExpBSRType; // SLong version exp(sqrt(2.0)) 3.6(sec) in 40,000 decimals
// typedef SDouble ExpBSRType;  // SDouble version  4.2 (sec)

/******************************************************
It returns the value exp(n/d) as a rational number a/c.
******************************************************/
// function ID = 3317 ver. 2.18
static SDouble C;

void ExpBSR(const SLong& n, const SLong& d, SLong& a, SLong& c) {
    long prec = long(C.EffFig() + C.Hidden()) * DFIGURES;
    double log10x = n.DFigures() - d.DFigures();
    if(log10x > 0) C.SetError(C.SYNTAX_ERR, func, 3317);
    long L = upToExpSeries(prec, log10x + 1);
    ExpBSRationalNumber<ExpBSRType> expX(L, prec, n, d);    // defined in "sbstempl.h"

    expX.putTogether();
    a = expX.getA();    c = expX.getC();    //  expX.getAC(a, c);
}
/**********************************************************
 It evaluates exp(n/d). Condition n < d must be satisfied.
******************************************************/
// function ID = 3316 ver. 2.18
SDouble ExpBSR(const SLong& n, const SLong& d) {
    SLong a, c;

    ExpBSR(n, d, a, c);

    return SDouble(a) / SDouble(c);
}