1 files changed, 43 insertions, 0 deletions
diff --git a/buch/chapters/040-rekursion/images/loggammaplot.m b/buch/chapters/040-rekursion/images/loggammaplot.m
new file mode 100644
index 0000000..5456e4f
--- /dev/null
+++ b/buch/chapters/040-rekursion/images/loggammaplot.m
@@ -0,0 +1,43 @@
+#
+# loggammaplot.m
+#
+# (c) 2022 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule
+#
+xmax = 10;
+xmin = 0.1;
+N = 500;
+
+fn = fopen("loggammadata.tex", "w");
+
+fprintf(fn, "\\def\\loggammapath{\n ({%.4f*\\dx},{%.4f*\\dy})",
+	xmax, log(gamma(xmax)));
+xstep = (xmax - 1) / N;
+for x = (xmax:-xstep:1)
+	fprintf(fn, "\n\t-- ({%.4f*\\dx},{%.4f*\\dy})", x, log(gamma(x)));
+endfor
+for k = (0:0.2:10)
+	x = exp(-k);
+	fprintf(fn, "\n\t-- ({%.4f*\\dx},{%.4f*\\dy})", x, log(gamma(x)));
+endfor
+fprintf(fn, "\n}\n");
+
+function retval = lgp(fn, x0, name)
+	fprintf(fn, "\\def\\loggammaplot%s{\n", name);
+	fprintf(fn, "\\draw[color=red,line width=1pt] ");
+	for k = (-7:0.1:7)
+		x = x0 + 0.5 * tanh(k);
+		if (k > -5)
+			fprintf(fn, "\n\t-- ");
+		end
+		fprintf(fn, "({%.4f*\\dx},{%.4f*\\dy})", x, log(gamma(x)));
+	endfor
+	fprintf(fn, ";\n}\n");
+endfunction
+
+lgp(fn, -0.5, "zero");
+lgp(fn, -1.5, "one");
+lgp(fn, -2.5, "two");
+lgp(fn, -3.5, "three");
+lgp(fn, -4.5, "four");
+
+fclose(fn);