From 45f12ba19761024d335407793ffb8d4823b28149 Mon Sep 17 00:00:00 2001
From: justanothercatgirl <sotov2070@gmail.com>
Date: Tue, 15 Apr 2025 00:51:40 +0300
Subject: Started doing 207

---
 libprakpp/include/prakmath.hpp | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'libprakpp/include/prakmath.hpp')

diff --git a/libprakpp/include/prakmath.hpp b/libprakpp/include/prakmath.hpp
index ebd02bf..bb09e74 100644
--- a/libprakpp/include/prakmath.hpp
+++ b/libprakpp/include/prakmath.hpp
@@ -289,6 +289,22 @@ pvalue<T> function(function_t<T> func, const std::vector<pvalue<T>> &args) {
 	return ret;
 }
 
+template <typename iterator, typename T = iterator::value_type>
+requires requires(iterator a){ ++a; *a; } && (std::integral<T> || std::floating_point<T>)
+T discrete_integral_trapezoid(iterator X_start, iterator X_end, iterator Y_start, iterator Y_end)
+{
+	T ret = 0;
+	for (T Xl = *X_start, Yl = *Y_start; 
+	     X_start != X_end && Y_start != Y_end; 
+	     ++X_start, ++Y_start) 
+	{
+		ret += std::abs(*X_start - Xl) * (*Y_start + Yl) / 2; // first iteration will add 0
+		Xl = *X_start;
+		Yl = *Y_start;
+	}
+	return ret;
+}
+
 /// calculate least-squares linear approximation to fit data
 /// ax+b = y (ss is an error of Y value)
 template <std::floating_point T>
-- 
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