June 2018 Update

Task/Gamma-function/Julia/gamma-function-1.julia

@@ -1 +1 @@
-gamma(x)
+@show gamma(1)

Task/Gamma-function/Julia/gamma-function-2.julia

@@ -1,4 +1,3 @@
-gamma_quad(t) = quadgk(x -> x^(t-1)*exp(-x), zero(t), inf(t), reltol=100*eps(t))[1]
-
-# generalize to handle arrays of inputs:
-@vectorize_1arg Real gamma_quad
+using QuadGK
+gammaquad(t::Float64) = first(quadgk(x -> x ^ (t - 1) * exp(-x), zero(t), Inf, reltol = 100eps(t)))
+@show gammaquad(1.0)

Task/Gamma-function/Maple/gamma-function.maple

@@ -0,0 +1,4 @@
+GAMMA(17/2);
+GAMMA(7*I);
+M := Matrix(2, 3, 'fill' = -3.6);
+MTM:-gamma(M);

Task/Gamma-function/Stata/gamma-function.stata

@@ -0,0 +1,42 @@
+mata
+_gamma_coef = 1.0,
+5.7721566490153286061e-1,-6.5587807152025388108e-1,
+-4.2002635034095235529e-2,1.665386113822914895e-1,
+-4.2197734555544336748e-2,-9.6219715278769735621e-3,
+7.2189432466630995424e-3,-1.1651675918590651121e-3,
+-2.1524167411495097282e-4,1.2805028238811618615e-4,
+-2.0134854780788238656e-5,-1.2504934821426706573e-6,
+1.1330272319816958824e-6,-2.0563384169776071035e-7,
+6.1160951044814158179e-9,5.0020076444692229301e-9,
+-1.1812745704870201446e-9,1.0434267116911005105e-10,
+7.782263439905071254e-12,-3.6968056186422057082e-12,
+5.100370287454475979e-13,-2.0583260535665067832e-14,
+-5.3481225394230179824e-15
+
+function gamma_(x_) {
+	external _gamma_coef
+	x = x_
+	for (y=1; x>2;) y = --x*y
+	z = _gamma_coef[24]
+	x--
+	for (i=23; i>=1; i--) z = z*x+_gamma_coef[i]
+	return(y/z)
+}
+
+function map(f,a) {
+	n = rows(a)
+	p = cols(a)
+	b = J(n,p,.)
+	for (i=1; i<=n; i++) {
+		for (j=1; j<=p; j++) {
+			b[i,j] = (*f)(a[i,j])
+		}
+	}
+	return(b)
+}
+
+x=(1::10000)/100
+u=map(&gamma(),x)
+v=map(&gamma_(),x)
+max(abs((u-v):/u))
+end