Add a constrained parameter to map_range()

[lesamouraipourpre]

Add a constrained parameter to map_range(), defaulting to True.
This allows for the conversion of unconstrained ranges, eg. Celsius to Fahrenheit.

[dhalbert]

Rather than add a control parameter to the original function, how about creating a new function with a different name that is an unconstrained map_range()? It is really a particular kind of linear transformation, though getting into the linear algebra of linear transformations is beyond what most people want to cope with.
map_range() can call this new function to do the mapping, and then do the constraining itself.

I am not sure what to call this new function. Let's think about it.

[lesamouraipourpre]

One option would simply be unconstrained_map_range.
Another would be map_calibration. This comes from another example that just dawned on me of having a sensor where we take calibration readings,eg:

sensor_calibration_1 = read_sensor() # at known_real_world_value_1
sensor_calibration_2 = read_sensor() # at known_real_world_value_2
# This obviously assumes linear behaviour between the sensor value and the real world value

current_sensor_value = read_sensor()
real_world_value = map_calibration(
    current_sensor_value,
    sensor_calibration_1,
    sensor_calibration_2,
    known_real_world_value_1,
    known_real_world_value_2
)

[dhalbert]

One option would simply be unconstrained_map_range.
Another would be map_calibration. This comes from another example that just dawned on me of having a sensor where we take calibration readings,eg:

unconstrained_map_range() is straightforward. map_calibration() describes a use case. Your temperature conversion example is really easy to explain, but is not a calibration. So I like the former better.

[lesamouraipourpre]

Slight tangent; are you able to run the tests locally?
They don't trigger for me when I run pre-commit run --all-files, I'm not sure if they should.
If I run pytest in the Adafruit_CircuitPython_SimpleMath it fails to run with the following errors:

pi in strawberry in Adafruit_CircuitPython_SimpleMath on  unconstrained-map-range via 🐍 v3.7.3 (testspace)
❯ pytest
================================================= test session starts ==================================================
platform linux -- Python 3.7.3, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
Test order randomisation NOT enabled. Enable with --random-order or --random-order-bucket=<bucket_type>
rootdir: /XXXX/Adafruit_CircuitPython_SimpleMath
plugins: random-order-1.0.4, cov-2.11.1
collected 0 items / 2 errors

======================================================== ERRORS ========================================================
_______________________________________ ERROR collecting tests/constrain_test.py _______________________________________
ImportError while importing test module '/XXXX/Adafruit_CircuitPython_SimpleMath/tests/constrain_test.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/lib/python3.7/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/constrain_test.py:5: in <module>
    from adafruit_simplemath import constrain
E   ModuleNotFoundError: No module named 'adafruit_simplemath'
_______________________________________ ERROR collecting tests/map_range_test.py _______________________________________
ImportError while importing test module '/XXXX/Adafruit_CircuitPython_SimpleMath/tests/map_range_test.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/lib/python3.7/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/map_range_test.py:5: in <module>
    from adafruit_simplemath import map_range
E   ModuleNotFoundError: No module named 'adafruit_simplemath'
=============================================== short test summary info ================================================
ERROR tests/constrain_test.py
ERROR tests/map_range_test.py
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 2 errors during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
================================================== 2 errors in 0.38s ===================================================

[lesamouraipourpre]

Slight tangent; are you able to run the tests locally?

I figured an answer - use python -m pytest instead of pytest.

[dhalbert]

Thanks for the discussion on this, and making it more useful! I asked a couple of things.

[lesamouraipourpre]

While waiting for my vaccine today, I realised there's a better name for unconstrained_map_range.

map_unconstrained_range

If you want, I can change the name and do another push.

[dhalbert]

I the sound of map_unconstrained_range better too. Idle thinking is often the best. 🙂

[dhalbert]

This is great! Thanks for your work on this.