From 3a95957a38a1cc8bcd865459a75cda87a2a8b56c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20M=C3=BCller?= <andreas.mueller@ost.ch>
Date: Sat, 18 Jun 2022 21:41:57 +0200
Subject: add new image, stuff about hypergeometrich series

---
 buch/chapters/040-rekursion/images/0f1.cpp | 94 ++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 buch/chapters/040-rekursion/images/0f1.cpp

(limited to 'buch/chapters/040-rekursion/images/0f1.cpp')

diff --git a/buch/chapters/040-rekursion/images/0f1.cpp b/buch/chapters/040-rekursion/images/0f1.cpp
new file mode 100644
index 0000000..24ca3f1
--- /dev/null
+++ b/buch/chapters/040-rekursion/images/0f1.cpp
@@ -0,0 +1,94 @@
+/*
+ * 0f1.cpp
+ *
+ * (c) 2022 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule
+ */
+#include <cstring>
+#include <cstdio>
+#include <cstdlib>
+#include <cmath>
+#include <string>
+#include <iostream>
+#include <fstream>
+
+static int	N = 100;
+static double	xmin = -50;
+static double	xmax =  30;
+static int	points = 200;
+
+double	f(double b, double x) {
+	double	s = 1;
+	double	p = 1;
+	for (int k = 1; k < N; k++) {
+		p = p * x / (k * (b + k - 1.));
+		s += p;
+	}
+	return s;
+}
+
+typedef	std::pair<double, double> point_t;
+
+point_t	F(double b, double x) {
+	return std::make_pair(x, f(b, x));
+}
+
+std::string	ff(double f) {
+	if (f > 1000) { f = 1000; }
+	if (f < -1000) { f = -1000; }
+	char	b[128];
+	snprintf(b, sizeof(b), "%.4f", f);
+	return std::string(b);
+}
+
+std::ostream&	operator<<(std::ostream& out, const point_t& p) {
+	char	b[128];
+	out << "({" << ff(p.first) << "*\\dx},{" << ff(p.second) << "*\\dy})";
+	return out;
+}
+
+void	curve(std::ostream& out, double b, const std::string& name) {
+	double	h = (xmax - xmin) / points;
+	out << "\\def\\kurve" << name << "{";
+	out << std::endl << "\t" << F(b, xmin);
+	for (int i = 1; i <= points; i++) {
+		double	x = xmin + h * i;
+		out << std::endl << "\t-- " << F(b, x);
+	}
+	out << std::endl;
+	out << "}" << std::endl;
+}
+
+int	main(int argc, char *argv[]) {
+	std::ofstream	out("0f1data.tex");
+
+	double	s = 13/(xmax-xmin);
+	out << "\\def\\dx{" << ff(s) << "}" << std::endl;
+	out << "\\def\\dy{" << ff(s) << "}" << std::endl;
+	out << "\\def\\xmin{" << ff(s * xmin) << "}" << std::endl;
+	out << "\\def\\xmax{" << ff(s * xmax) << "}" << std::endl;
+
+	curve(out, 0.5, "one");
+	curve(out, 1.5, "two");
+	curve(out, 2.5, "three");
+	curve(out, 3.5, "four");
+	curve(out, 4.5, "five");
+	curve(out, 5.5, "six");
+	curve(out, 6.5, "seven");
+	curve(out, 7.5, "eight");
+	curve(out, 8.5, "nine");
+	curve(out, 9.5, "ten");
+
+	curve(out,-0.5, "none");
+	curve(out,-1.5, "ntwo");
+	curve(out,-2.5, "nthree");
+	curve(out,-3.5, "nfour");
+	curve(out,-4.5, "nfive");
+	curve(out,-5.5, "nsix");
+	curve(out,-6.5, "nseven");
+	curve(out,-7.5, "neight");
+	curve(out,-8.5, "nnine");
+	curve(out,-9.5, "nten");
+	
+	out.close();
+	return EXIT_SUCCESS;
+}
-- 
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