/*  sdfsfast.cpp  by K.Tsuru  */
// function ID 3053   DRADIX
/*********************************************************************************
SDouble class
It returs that the SDouble series is faster than the SDecimal one
or not.
1. When x is short and a recurring decimal in the binary radix,the
 D***Series is faster.It may be better to examine that x is also a short value
 in the binary radix(e.g. 0.25), but it will be a rare case.
2.For the relatively long number B***Series is faster even if including the
 time costed by the radix conversion.
3.When |x| is very small, the number of terms is little and the radix conversion
costs a much time. Then D***Series is faster.

This is for the trigonometric functions having a general term as x^n/n!.
For the series whose convergence is late(e.g.AtanSeries) it needs other conditions.
**********************************************************************************/
#ifndef SN_H
#include "sn.h"
#endif
bool DSeriesIsFast(const SDouble& x){
    uint xfig = x.Last() - x.First()+1u, ef = x.MaxSize();
    int xe = x.RdxExp();
    bool fast = false;
    if(xe <= -10) return true;
    if( (xfig < 32u) || (ef > 1024u) ) return true;

    if(xfig < 255u){
        if(xe <= -9) fast = true;
    } else if(xfig < 510u){
        if(xe <= -5) fast = true;
    }
    return fast;
}