LOG_GAMMA — Logarithm of the Gamma functionLOG_GAMMA(X) computes the natural logarithm of the absolute value
of the Gamma (\Gamma) function.
     X = LOG_GAMMA(X)
     | X | Shall be of type REALand neither zero
nor a negative integer. | 
REAL of the same kind as X.
               program test_log_gamma
            real :: x = 1.0
            x = lgamma(x) ! returns 0.0
          end program test_log_gamma
     | Name | Argument | Return type | Standard | 
| LGAMMA(X) | REAL(4) X | REAL(4) | GNU Extension | 
| ALGAMA(X) | REAL(4) X | REAL(4) | GNU Extension | 
| DLGAMA(X) | REAL(8) X | REAL(8) | GNU Extension |