/// <summary>
/// if num is ABC, the initial number was 0.ABC
/// </summary>
/// <param name="num"></param>
/// <param name="N"></param>
/// <returns></returns>
internal static EDecimal FloatFromBaseN(string num, int N)
{
EDecimal res = 0;
for (int i = 0; i < num.Length; i++)
{
char digit = num[i];
res = RealNumber.CtxAdd(res, RealNumber.CtxDivide(ALPHABET_FROMCHAR[digit], EDecimal.FromInt32(N).Pow(i + 1)));
}
return(res);
}
private static EDecimal PiOver(int a) => RealNumber.CtxDivide(RealNumber.CtxMultiply(2, MathS.DecimalConst.pi), a);
