OpenMDAO Bridge for Excel

A reusable component for running Excel analyses from OpenMDAO. It uses xlwings to communicate with Excel and works through the following procedure:

1. Start Excel.
2. Open a pre-defined workbook file.
3. Optional: Run pre-calculation macros.
4. Set the input variables in corresponding ranges/cells.
5. Optional: Run main macros.
6. Read values of the output ranges/cells and assign to output variables.
7. Optional: Run post-calculation macros.
8. Close the workbook without saving it.

Features:

• Cells can be addressed by named ranges (use them!) or regular means (e.g. C3).
• Timeout handling by mercilessly killing the Excel process after a specified number of seconds.
• The Excel process will be kept alive between evaluations, unless the previous one timed out.
• The macro runner will try to catch and log macro errors, raising an OpenMDAO AnalysisError.
• Rudimentary logging using the Python logging system.

Non-features/pitfalls/known issues:

• "Trust access to the VBA project object model" must be enabled.
• MacOS has not been tested and will probably not work.
• Non-scalar values (i.e. ranges with more than one cell) have not been tested and will probably not work.
• Multi-processing (i.e. MPI) has not been tested, but might work.
• Excel has a few numeric quirks and you are encouraged to be very critical of your results. I personally don't even recommend using Excel in this context, unless you really have to.
• The timeout handler runs in a separate Python thread. This shouldn't be a problem, but you might want to know.

Compatibility

The component is regularly-ish tested on the latest stable versions of:

• Windows 10, 64-bit
• Microsoft Excel, 32-bit
• Python 3
• OpenMDAO

I wish I could set up a CI pipeline to make this process more transparent and repeatable, but Excel being a proprietary product makes this more or less impossible.

Installation

pip install git+https://github.com/ovidner/openmdao-bridge-excel.git#egg=openmdao_bridge_excel

Usage example

import openmdao.api as om
from openmdao_bridge_excel import ExcelComponent, ExcelVar

prob = om.Problem()
...
excel_comp = prob.add_subsystem("excel", ExcelComponent(
  file_path="absolute/or/relative/path/to/file.xlsm",
  pre_macros=["foo", "bar"],
  main_macros=["main", "foo"],
  post_macros=["cleanup"],
  inputs=[
    ExcelVar("in_1", "Sheet1!C2"),
    ExcelVar("in_2", "NamedRangesAreSupported"),
  ],
  outputs=[
    ExcelVar("out_1", "B1"),
    ExcelVar("out_2", "AnotherNamedRange"),
  ],
  timeout=60,  # One minute
))
...

Input/output variables can then be addressed on the OpenMDAO component as usual (e.g. excel.in_1, excel.out_2).

Development environment setup

This is automagically handled with anaconda-project:

anaconda-project run setup

You should then be able to run the tests:

anaconda-project run pytest