Initial commit

1 files changed, 27 insertions, 0 deletions

diff --git a/graphics/asymptote/doc/penfunctionimage.asy b/graphics/asymptote/doc/penfunctionimage.asy
new file mode 100644
index 0000000000..38951e550d
--- /dev/null
+++ b/graphics/asymptote/doc/penfunctionimage.asy
@@ -0,0 +1,27 @@
+import palette;
+
+size(200);
+
+real fracpart(real x) {return (x-floor(x));}
+
+pair pws(pair z) {
+  pair w=(z+exp(pi*I/5)/0.9)/(1+z/0.9*exp(-pi*I/5));
+  return exp(w)*(w^3-0.5*I);
+}
+
+int N=512;
+
+pair a=(-1,-1);
+pair b=(0.5,0.5);
+real dx=(b-a).x/N;
+real dy=(b-a).y/N;
+
+pen f(int u, int v) {
+  pair z=a+(u*dx,v*dy);
+  pair w=pws(z);
+  real phase=degrees(w,warn=false);
+  real modulus=w == 0 ? 0: fracpart(log(abs(w)));
+  return hsv(phase,1,sqrt(modulus));
+}
+
+image(f,N,N,(0,0),(300,300),antialias=true);