thinking-processes 1.0.0

Diagramming tools for the Thinking Processes from the Theory of Constraints

Thinking Processes

This Python package helps you to draw diagrams used in the Thinking Processes from the Theory of Constraints. For more information, see https://en.wikipedia.org/wiki/Thinking_processes_(theory_of_constraints)

Prerequisites

Python 3.11+

Installing

pip install thinking-processes

Current Reality Tree

In this example, we find root causes for undesired effects by drawing a Current Reality Tree:

from thinking_processes import CurrentRealityTree

crt = CurrentRealityTree()
        
engine_not_start = crt.add_node("Car's engine will not start")
engine_needs_fuel = crt.add_node('Engine needs fuel in order to run')
no_fuel_to_engine = crt.add_node('Fuel is not getting to the engine')
water_in_fuel_line = crt.add_node('There is water in the fuel line')
crt.add_causal_relation([engine_needs_fuel, no_fuel_to_engine], engine_not_start)
crt.add_causal_relation([water_in_fuel_line], no_fuel_to_engine)

air_conditioning_not_working = crt.add_node('Air conditioning is not working')
air_not_circulating = crt.add_node('Air is not able to circulate')
air_intake_full_of_water = crt.add_node('The air intake is full of water')
crt.add_causal_relation([air_not_circulating], air_conditioning_not_working)
crt.add_causal_relation([air_intake_full_of_water], air_not_circulating)

radio_distorted = crt.add_node('Radio sounds distorted')
speakers_obstructed = crt.add_node('The speakers are obstructed')
speakers_underwater = crt.add_node('The speakers are underwater')
crt.add_causal_relation([speakers_obstructed], radio_distorted)
crt.add_causal_relation([speakers_underwater], speakers_obstructed)

car_in_pool = crt.add_node('The car is in the swimming pool')
crt.add_causal_relation([car_in_pool], speakers_underwater)
crt.add_causal_relation([car_in_pool], air_intake_full_of_water)
crt.add_causal_relation([car_in_pool], water_in_fuel_line)

handbreak_faulty = crt.add_node('The handbreak is faulty')
handbreak_stops_car = crt.add_node('The handbreak stops the car from rolling into the swimming pool')
crt.add_causal_relation([handbreak_faulty, handbreak_stops_car], car_in_pool)

crt.plot(view=True, filepath='crt.png')

The resulting tree looks like this:

Evaporating Cloud (Conflict Resolution Diagram)

In this example, we resolve a conflict by identifying wrong assumptions behind the conflict:

from thinking_processes import EvaporatingCloud

ec = EvaporatingCloud(
    objective='Reduce cost per unit',
    need_a='Reduce setup cost per unit',
    need_b='Reduce carrying cost per unit',
    conflict_part_a='Run larger batches',
    conflict_part_b='Run smaller batches'
)

ec.add_assumption_on_the_conflict('small is the opposite of large', is_true=True)
ec.add_assumption_on_the_conflict('there is only one meaning to the word "batch"', is_true=False)
ec.add_assumption_on_need_a("setup cost is fixed and can't be reduced")
ec.add_assumption_on_need_a("the machine being set up is a bottleneck with no spare capacity")
ec.add_assumption_on_need_b("smaller batches reduce carrying cost")

ec.plot(view=True, filepath='ec.png')

The resulting diagram looks like this:

Future Reality Tree

In this example, we introduce injections to achieve desired effects:

from thinking_processes import FutureRealityTree
frt = FutureRealityTree()
        
engine_starts = frt.add_desirable_effect("Car's engine will start")

build_fence = frt.add_injection("Build a fence between road and pool")
frt.add_negative_effect(build_fence, 'Car can roll into the fence')

cannot_roll_into_pool = frt.add_intermediate_effect("Car parked at the road does not roll into the pool")
no_water_in_fuel_line = frt.add_intermediate_effect("There is no water in the fuel line")
fuel_to_the_engine = frt.add_intermediate_effect("Fuel is getting to the engine")

frt.add_causal_relation([build_fence], cannot_roll_into_pool)
frt.add_causal_relation([cannot_roll_into_pool], no_water_in_fuel_line)
frt.add_causal_relation([no_water_in_fuel_line], fuel_to_the_engine)
frt.add_causal_relation([fuel_to_the_engine], engine_starts)

airintake = frt.add_intermediate_effect("Air intake is free of water")
air_circulation = frt.add_intermediate_effect("Air is able to circulate")
ac_working = frt.add_desirable_effect("Air conditioning is working")
frt.add_causal_relation([cannot_roll_into_pool], airintake)
frt.add_causal_relation([airintake], air_circulation)
frt.add_causal_relation([air_circulation], ac_working)

radio_sounds_good = frt.add_desirable_effect("Radio sounds good")
speakers_not_underwater = frt.add_intermediate_effect("Speakers are not underwater")
frt.add_causal_relation([cannot_roll_into_pool], speakers_not_underwater)
frt.add_causal_relation([speakers_not_underwater], radio_sounds_good)

frt.plot(view=True, filepath='frt.png')

The resulting diagram looks like this:

Development

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Running the tests

All tests in the "tests" directory are based on the unittest package.

Deployment

make rm -R dist build thinking_processes.egg-info || python -m build && twine upload --skip-existing --verbose dist/*

You should also create a tag for the current version

git tag -a [version] -m "describe what has changed"
git push --tags

Versioning

We use SemVer for versioning.

Authors

If you have any questions, feel free to ask one of our authors:

• Boris Wiegand - [e-mail]