Creating Your First Block: Difference between revisions

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# Applies a mathematical operation to ''input_items'' and stores the result in ''output_items''
# Applies a mathematical operation to ''input_items'' and stores the result in ''output_items''
# Returns the number of samples produced
# Returns the number of samples produced
The example block we are going to create will either add or multiply the two blocks based on the input parameter ''example_param''. In order to do this, the ''work'' function will need to be modified.

Revision as of 18:21, 10 January 2022

This tutorial will guide you through creating your first block with the Embedded Python Block. The previous tutorial is here: Streams and Vectors

Embedded Python Block

The Embedded Python Block is a tool to quickly prototype a block within a flowgraph. Search for the Python Block and add it to the workspace:

AddPythonBlockToWorkspace.png


Double-click the box to edit the properties. The Embedded Python Block has two properties,

  1. Code, a click-box which contains a link to the Python code for the block and
  2. Example_Param, an input parameter to the block.


Click on Open in Editor to edit the Python code:

EmbeddedPythonBlockProperties.png


You will be prompted with another choice for which editor to use to write the Python code. Click Use Default:

ClickUseDefault.png


An editor window will then display the Python code for the Embedded Python Block:

PythonCodeGedit.png


Editing Python Block Code

There are three important sections in the Python block code:

  1. import statements in green
  2. __init__ function in orange
  3. work function in red

PythonBlockCodeFunctions.png


The import statement includes the NumPy and GNU Radio libraries.

The __init__ statement:

  1. Accepts the example_param parameter with a default argument of 1.0
  2. Declares the block to have a np.complex64 input and output, which is the GNU Radio Complex Float 32 data type
  3. Stores the self.example_param variable from the input parameter

The work function:

  1. Has the input input_items and output output_items parameters
  2. Applies a mathematical operation to input_items and stores the result in output_items
  3. Returns the number of samples produced


The example block we are going to create will either add or multiply the two blocks based on the input parameter example_param. In order to do this, the work function will need to be modified.