Merge pull request #34 from bendudson/misc-docs

Add some documentation on python-getattr

README.org

@@ -232,6 +232,20 @@ specifying the method, followed by any arguments:
 #+RESULTS:
 : 3
 
+** Getting python attributes: =python-getattr=
+
+The attributes of a python object can be accessed using the generic
+functon =python-getattr=, with the python object as first argument and
+a string as the name of the attribute:
+#+BEGIN_SRC lisp
+(py4cl:python-getattr '(1 2 3) "__doc__")
+#+END_SRC
+
+
+Note: Methods for this function can also be defined for lisp classes,
+enabling python code to access attributes of lisp objects. See below
+for details.
+
 ** Chaining python methods: =chain=
 
 In python it is quite common to apply a chain of method calls, data

docs/matplotlib.org

@@ -250,6 +250,72 @@ in addition to the =np= and =plt= modules already loaded:
 #+RESULTS:
 : NIL
 
+or a slightly more efficient method, using =remote-objects=:
+#+BEGIN_SRC lisp
+(defun f (x y)
+  (* 
+    (+ 1 (* -0.5 x) (expt x 5) (expt y 3))
+    (exp (- 0 (* x x) (* y y)))))
+
+(py4cl:remote-objects
+(let* ((n 256)
+       (xy (np:meshgrid (np:linspace -3 3 n) 
+                        (np:linspace -3 3 n)))
+       (x (py4cl:chain xy 0))
+       (y (py4cl:chain xy 1)))
+
+  (plt:axes #(0.025 0.025 0.95 0.95))
+
+  (plt:contourf x y (py4cl:python-call (np:vectorize #'f) x y) 8 :alpha 0.75)
+
+  (let ((c (plt:contour x y (py4cl:python-call (np:vectorize #'f) x y) 8 :colors "black" :linewidth 0.5)))
+    (plt:clabel c :inline 1 :fontsize 10))))
+
+(plt:xticks #())
+(plt:yticks #())
+(plt:show)
+#+END_SRC
+
+#+RESULTS:
+: NIL
+
+The majority of the time is spent in calling lisp for every point in (x,y). We could
+just do the calculation in lisp using =array-operations=:
+#+BEGIN_SRC lisp
+(ql:quickload :array-operations)
+#+END_SRC
+
+#+RESULTS:
+| :ARRAY-OPERATIONS |
+
+#+BEGIN_SRC lisp
+(defun f (x y)
+  (* 
+    (+ 1 (* -0.5 x) (expt x 5) (expt y 3))
+    (exp (- 0 (* x x) (* y y)))))
+
+(let* ((n 256)
+       (xy (np:meshgrid (np:linspace -3 3 n) 
+                        (np:linspace -3 3 n)))
+       (x (aref xy 0))
+       (y (aref xy 1))
+       (z (aops:vectorize (x y) (f x y))))
+
+  (plt:axes #(0.025 0.025 0.95 0.95))
+
+  (plt:contourf x y z 8 :alpha 0.75)
+
+  (let ((c (plt:contour x y z 8 :colors "black" :linewidth 0.5)))
+    (plt:clabel c :inline 1 :fontsize 10)))
+
+(plt:xticks #())
+(plt:yticks #())
+(plt:show)
+#+END_SRC
+
+#+RESULTS:
+: NIL
+
 ** 3D plots
 
 #+CAPTION: A simple example of 3D plotting.
@@ -287,3 +353,4 @@ in addition to the =np= and =plt= modules already loaded:
 
 #+RESULTS:
 : NIL
+