more buffer functionality (support sequence and number protocols)

more examples
preset sys.argv for module loading
support for buffer objects (preliminary)

svn path=/trunk/; revision=2615

1 files changed, 32 insertions, 18 deletions

diff --git a/externals/grill/py/scripts/buffer.py b/externals/grill/py/scripts/buffer.py
index 4c81caab..19b6f5d3 100644
--- a/externals/grill/py/scripts/buffer.py
+++ b/externals/grill/py/scripts/buffer.py
@@ -7,12 +7,9 @@
 

 """This is an example script for the py/pyext object's buffer support.

 

-PD/Max buffers can be imported to and exported from numarray arrays.

+PD/Max buffers can be mapped to numarray arrays.

 For numarray see http://numeric.scipy.org

-It will probably once be replaced by Numeric

-

-- _import(buffer): copy contents from the buffer to a new numarray object

-- _export(buffer,numarray): export contents of numarray object to the buffer

+It will probably once be replaced by Numeric(3)

 """

 

 import sys

@@ -20,7 +17,7 @@ import sys
 try:

     import pyext

 except:

-    print "ERROR: This script must be loaded by the PD/Max pyext external"

+    print "ERROR: This script must be loaded by the PD/Max py/pyext external"

 

 try:    

     from numarray import *

@@ -28,19 +25,36 @@ except:
     print "Failed importing numarray module:",sys.exc_value

 

 def mul(*args):

+    # create buffer objects

+    # as long as these variables live the underlying buffers are locked

     c = pyext.Buffer(args[0])

-    dst = c.array()

-    dst[:] = 0

-    a = pyext.Buffer(args[1]).array()

-    b = pyext.Buffer(args[2]).array()

-    dst += a*b

-    c.dirty()   

+    a = pyext.Buffer(args[1])

+    b = pyext.Buffer(args[2])

+

+    # slicing causes numarrays (mapped to buffers) to be created

+    # note the c[:] - to assign contents you must assign to a slice of the buffer

+    c[:] = a[:]*b[:]  

 

 def add(*args):

     c = pyext.Buffer(args[0])

-    dst = c.array()

-    dst[:] = 0

-    a = pyext.Buffer(args[1]).array()

-    b = pyext.Buffer(args[2]).array()

-    dst += a+b

-    c.dirty()   

+    a = pyext.Buffer(args[1])

+    b = pyext.Buffer(args[2])

+

+    # this is also possible, but is probably slower

+    # the + converts a into a numarray, the argument b is taken as a sequence

+    # depending on the implementation in numarray this may be as fast

+    # as above or not

+    c[:] = a+b  

+

+def fadein(target):

+    a = pyext.Buffer(target)

+    # in place operations are ok

+    a *= arange(len(a),type=Float32)/len(a)

+

+def neg(target):

+    a = pyext.Buffer(target)

+    # in place transformation (see numarray ufuncs)

+    negative(a[:],a[:])

+    # must mark buffer content as dirty to update graph

+    # (no explicit assignment occurred)

+    a.dirty()