Pulse Sequence Programming
==========================

In this user guide, all the dashboard and Notebook examples shown thus far have used pre-written pulse sequence files. It is important to note, however, that you can write your own novel pulse sequences and execute them on *ilumr*.

On *ilumr*, pulse sequences are defined in python program files (.py) and run in notebooks (.ipynb). As an optional step, you can plot your pulse sequence file offline before running it on *ilumr*.

Program File (.py)
------------------

This file is typically used to:

* Define the pulse sequence parameters
* Set hardware options
* Define the data layout
* Calculate the timing parameters
* Send commands to the ilumr hardware using yield statements

To create a new python program file:

1. Click the **+** button in the file browser to open the Launcher tab.
2. Click the **Python 3** button under the **Other** heading.


.. figure:: /images/pythonfile.png
   :width: 100%
   :alt: python file button

   Create Python File

*ilumr’s* inbuilt pulse sequence program files can be found in **system > programs**. The system folder is read only. If you want to modify an existing pulse sequence file, you will need to copy the file into a new folder.

If you’re new to pulse programming on the *ilumr*, the :ref:`matipo/usage:Writing Custom Pulse Sequence Programs` section is a great place to get started.


Pulse Sequence Plotting Tool
----------------------------

The offline pulse sequence plotting tool is a useful way to visualize your program files and make sure your timing parameters have been set correctly. You can visit our `forum post <https://resonint.discourse.group/t/ilumr-pulse-sequence-plotting-tool/37>`_ to download the beta version of this tool.

.. figure:: /images/pulse_sequence.png
   :width: 100%
   :alt: pulse sequence plotting tool

   Plotted RARE Pulse Sequence

Running the Pulse Sequence in a Notebook (.ipynb)
-------------------------------------------------

To run your pulse sequence in a Notebook, you will need some boilerplate code to:

* Load the pulse sequence program file
* Load any relevant global variables
* Set the pulse sequence parameters
* Run the pulse sequence
* Process the data

More information on setting up a Notebook to run your custom pulse sequence can be found in the :ref:`matipo/usage:Running a Pulse Sequence` section.