Enhanced comments in 'graph.py' of example simpledsp (#103)

# Include definitions from the Python package to

# define datatype for the IOs and to have access to the

# Graph class

# Include definitions from the Python package to define data types for the IOs 

# and to access to the classes for the Graph Graph.

from cmsisdsp.cg.scheduler import *

# Include definition of the nodes

# Include definition of the processing nodes defined in 'nodes.py'.

from nodes import * 

# Define the datatype we are using for all the IOs in this

# example

# Define data type 'float' used for all IOs in this example

floatType=CType(F32)

# Instantiate a Source node with a float datatype and

# working with packet of 5 samples (each execution of the

# source in the C code will generate 5 samples)

# "source" is the name of the C variable that will identify

# this node

# Instantiate a Source processing node that creates a packet of 5 samples.

# Each execution of the C function "source" generates 5 samples.

src=Source("source",floatType,5)

# Instantiate a Processing node using a float data type for

# both the input and output. The number of samples consumed

# on the input and produced on the output is 7 each time

# the node is executed in the C code

# "processing" is the name of the C variable that will identify

# this node

# Instantiate a binary operation processing node with 2 inputs and 1 output.

# Each execution of the C function "arm_offset_f32" consumes and produces 7 samples. 

processing=Binary("arm_offset_f32",floatType,7)

# Instantiate a processing node that produces a constant value which is defined

# with the C identifier "OFFSET_VALUE".

offsetValue=Constant("OFFSET_VALUE")

# Instantiate a Sink node with a float datatype and consuming

# 5 samples each time the node is executed in the C code

# "sink" is the name of the C variable that will identify

# this node

# Instantiate a Sink processing node that consumes a packet of 5 samples.

# Each execution of the C function "sink" gets 5 samples as input.

sink=Sink("sink",floatType,5)

# Create a Graph object

# Create a Compute Graph object.

the_graph = Graph()

# Connect the source to the processing node

# Connect the source output to the input ia of the processing node.

the_graph.connect(src.o,processing.ia)

# Connect the constant offsetValues to the input ib of the processing node.

the_graph.connect(offsetValue,processing.ib)

# Connect the processing node to the sink

# Connect the ouput of the processing node to the input of the sink.

the_graph.connect(processing.o,sink.i)