Better makefile, plotting, saving the data, and cleanup

shell.nix

@@ -0,0 +1,10 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+pkgs.mkShell {
+  buildInputs = with pkgs; [
+    (pkgs.python313.withPackages (p: with p; [
+      matplotlib
+      numpy
+    ]))
+  ];
+}