Add bin and edit workflow

bin/gems/facets-3.1.0/lib/standard/facets/math/tgamma.rb

@@ -0,0 +1,10 @@
+require 'facets/math/lgamma'
+
+module Math
+
+  # Exp of LGamma.
+  def self.tgamma(x)
+    exp(lngamma(x)) #exp(log(gamma(x).abs)
+  end
+
+end