From f251769a1c4850efae4a40b9b6bc98c2aaa4a4bc Mon Sep 17 00:00:00 2001
From: Antonin Portelli <antonin.portelli@me.com>
Date: Mon, 2 Nov 2015 16:17:59 +0000
Subject: [PATCH] Math: chi^2 p-value function from GSL

---
 lib/Math.cpp | 9 +++++++++
 lib/Math.hpp | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/lib/Math.cpp b/lib/Math.cpp
index db3a931..6658c3b 100644
--- a/lib/Math.cpp
+++ b/lib/Math.cpp
@@ -19,6 +19,7 @@
 
 #include <LatAnalyze/Math.hpp>
 #include <LatAnalyze/includes.hpp>
+#include <gsl/gsl_cdf.h>
 
 using namespace std;
 using namespace Latan;
@@ -90,3 +91,11 @@ DEF_STD_FUNC_2ARG(fmin)
 
 // Absolute value
 DEF_STD_FUNC_1ARG(fabs)
+
+// p-value
+auto chi2PValueVecFunc = [](const double arg[2])
+{
+    return gsl_cdf_chisq_Q(arg[0], arg[1]);
+};
+
+DoubleFunction MATH_NAMESPACE::chi2PValue(chi2PValueVecFunc, 2);
diff --git a/lib/Math.hpp b/lib/Math.hpp
index 84f2270..7f7f018 100644
--- a/lib/Math.hpp
+++ b/lib/Math.hpp
@@ -141,6 +141,15 @@ DECL_STD_FUNC(fmin)
 // Absolute value
 DECL_STD_FUNC(fabs)
 
+/******************************************************************************
+ *                                Other functions                             *
+ ******************************************************************************/
+// p-value
+namespace MATH_NAMESPACE
+{
+    extern DoubleFunction chi2PValue;
+}
+
 END_LATAN_NAMESPACE
 
 #endif // Latan_Math_hpp_