Seems that using higher precision Julia packages I’ve discovered that log(gamma( is related to PI ;
per using SpecialFunctions and using Nemo ?
using Julia SpecialFunctions and Nemo seems I’ve discovered that loggamma(-1 + 0i) = Infinity - i*pi (a Complex number) .
Also Wolframalpha answer is incomplete About: loggamma(-1 + 0i) or logΓ(-1 + 0 i)
Try this link loggamma(-1 + 0i) - Wolfram|Alpha
and you’ll see Wolframalpha shows loggamma(-1 + 0i) = Infinity
However it seems I’ve discovered/uncovered that loggamma(-1 + 0i) = Infinity - i*pi (a Complex number) per the following :
## show using SpecialFunctions
## loggamma(-1 + 0i) = Infinity - i*pi (a Complex number)
julia> loggamma(-1+0im)
Inf - 3.141592653589793im
julia> imag(loggamma(-1+0im))/pi
-1.0
## Showing Effects of error propagation ?
julia> log(gamma(-1+0im))
Inf - 2.356194490192345im
## Reconfirmed suspicion via show using Nemo to 64 Bits / 18 Decimals
using Nemo # for arbitrary precision math calculations
CC = ComplexField(64)
julia> using Nemo
julia> CC = ComplexField(64)
Complex Field with 64 bits of precision and error bounds
julia> RR = RealField(64)
Real Field with 64 bits of precision and error bounds
julia> Nemo.lgamma(RR("-1") + CC("0"))
nan + i*[-3.141592653589793238 +/- 5.14e-19]
julia> Nemo.const_pi(RR)
[3.141592653589793239 +/- 5.96e-19]
–
Also here’s an analytical/symbolic equation question :
Is this the same or a different fact than the Euler Identity ?
Maybe start here Gamma, Beta, Erf > LogGamma[z]
Representations through more general functions >> Logarithm of the gamma function: Representations through more general functions (subsection 26/01)