fixed dependencies

vendor/gonum.org/v1/gonum/mathext/gamma_inc.go

@@ -0,0 +1,58 @@
+// Copyright ©2016 The Gonum Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mathext
+
+import (
+	"gonum.org/v1/gonum/mathext/internal/cephes"
+)
+
+// GammaIncReg computes the regularized incomplete Gamma integral.
+//
+//	GammaIncReg(a,x) = (1/ Γ(a)) \int_0^x e^{-t} t^{a-1} dt
+//
+// The input argument a must be positive and x must be non-negative or GammaIncReg
+// will panic.
+//
+// See http://mathworld.wolfram.com/IncompleteGammaFunction.html
+// or https://en.wikipedia.org/wiki/Incomplete_gamma_function for more detailed
+// information.
+func GammaIncReg(a, x float64) float64 {
+	return cephes.Igam(a, x)
+}
+
+// GammaIncRegComp computes the complemented regularized incomplete Gamma integral.
+//
+//	GammaIncRegComp(a,x) = 1 - GammaIncReg(a,x)
+//	                     = (1/ Γ(a)) \int_x^\infty e^{-t} t^{a-1} dt
+//
+// The input argument a must be positive and x must be non-negative or
+// GammaIncRegComp will panic.
+func GammaIncRegComp(a, x float64) float64 {
+	return cephes.IgamC(a, x)
+}
+
+// GammaIncRegInv computes the inverse of the regularized incomplete Gamma integral. That is,
+// it returns the x such that:
+//
+//	GammaIncReg(a, x) = y
+//
+// The input argument a must be positive and y must be between 0 and 1
+// inclusive or GammaIncRegInv will panic. GammaIncRegInv should return a positive
+// number, but can return NaN if there is a failure to converge.
+func GammaIncRegInv(a, y float64) float64 {
+	return gammaIncRegInv(a, y)
+}
+
+// GammaIncRegCompInv computes the inverse of the complemented regularized incomplete Gamma
+// integral. That is, it returns the x such that:
+//
+//	GammaIncRegComp(a, x) = y
+//
+// The input argument a must be positive and y must be between 0 and 1
+// inclusive or GammaIncRegCompInv will panic. GammaIncRegCompInv should return a
+// positive number, but can return 0 even with non-zero y due to underflow.
+func GammaIncRegCompInv(a, y float64) float64 {
+	return cephes.IgamI(a, y)
+}