examples package

Submodules

examples.fourbar_linkage module

The fourbar_linkage module demonstrates the features of pylinkage.

It is not intended to be imported in another project, but feel welcome to copy-paste chunks of code.

Created on Sat Jun 19, 12:32:37 2021.

@author: HugoFara

examples.fourbar_linkage.define_linkage()

Define a simple four-bar linkage.

Returns:

A demo four-bar linkage.

Return type:

pylinkage.Linkage

examples.fourbar_linkage.main()

Define and optimize a demo linkage.

examples.inverted_stroke_engine module

An inverted four-stroke engine, that converts a rotary motion into a linear one.

See: https://en.wikipedia.org/wiki/Four-stroke_engine for details

examples.inverted_stroke_engine.create_stroke_engine_linkage()

Create an inverted stroke engine linkage.

examples.inverted_stroke_engine.view_linkage()

View a stroke engine linkage in action

examples.strider module

Kinematic Strider linkage, a type of walking linkage.

The original linkage can be found at https://www.diywalkers.com/strider-linkage-plans.html

examples.strider.LAP_PER_SECOND = 100

Parameters that can change without changing joints between objects.

Can be distance between joints, or an angle. Units are given relative to crank length, which is normalized to 1.

examples.strider.complete_strider(constraints, prev)

Take two sequences to define strider linkage.

Parameters:

  • constraints (tuple[float] | tuple[tuple[float]]) – The sequence of geometrical constraints.

  • prev (tuple[tuple[float, float]]) – Coordinates to set by default.

Return pylinkage.Linkage:

A strider linkage

examples.strider.history_saver(evaluator, history, linkage, dims, pos)

Save the history to a list.

Parameters:

  • evaluator – Evaluation function

  • history – History list

  • linkage – Input linkage

  • dims – Dimensions

  • pos – Initial positions

examples.strider.main()

Build and optimize a strider linkage.

You can find it at https://www.diywalkers.com/strider-linkage-plans.html

examples.strider.param2dimensions(param=(2, 0.7853981633974483, 1.8, 2.6, 1.4, 3.3415926535897933, 2.5, 1.8), flat=False)

Expand dimensions them to fit in strider.set_num_constraints.

Dimensions parameters are written in short form due to symmetry.

Parameters:

  • param – Short form for dimensions (Default value = DIMENSIONS)

  • flat – If the output should be a flat list (Default value = False)

Returns:

Expanded dimensions

examples.strider.show_optimized(linkage, data, n_show=10, duration=5, symmetric=True)

Show the optimized linkages.

Parameters:

  • linkage – Linkage to modify.

  • data – Linkage data

  • n_show – Number of linkages to show (Default value = 10)

  • duration – Duration of each animation (Default value = 5)

  • symmetric – If the input dimensions should be symmetric (Default value = True)

examples.strider.swarm_optimizer(linkage, dimensions=(2, 0.7853981633974483, 1.8, 2.6, 1.4, 3.3415926535897933, 2.5, 1.8), show=0, save_each=0, n_agents=300, n_iterations=400, *args)

Optimize linkage geometrically using PSO.

Parameters:

  • linkage (pylinkage.linkage.Linkage) – The linkage to optimize.

  • dimensions (list[float]) – The dimensions that should vary. Default value = DIMENSIONS.

  • show (int) – Type of visualization. The default is 0. - 0 to avoid any visualization - 1 for polar graph - 2 for tiled 2D representation

  • save_each (int) – If show is 0, save the image each {save_each} frame. The default is 0.

  • n_agents (int) – Number of agents to simulate. The default is 300.

  • n_iterations (int) – Number of iterations to run through. The default is 400.

  • args (list) – Arguments to pass to the particle swarm optimization.

Returns:

List of fittest linkages.

Return type:

list

examples.strider.sym_stride_evaluator(linkage, dimensions, initial_positions)

Give score to each dimension set for symmetric strider.

Parameters:

  • linkage (pylinkage.Linkage) – Input linkage

  • dimensions (tuple) – Dimensions

  • initial_positions (tuple) – Initial positions

Returns:

Score

Return type:

float

examples.strider.view_swarm_polar(linkage, dimensions=(2, 0.7853981633974483, 1.8, 2.6, 1.4, 3.3415926535897933, 2.5, 1.8), save_each=0, n_agents=300, n_iterations=400)

Draw an animation of the swarm in a polar graph.

Parameters:

  • linkage (pylinkage.Linkage) – Input linkage

  • dimensions (Sized) – Dimensions (Default value = DIMENSIONS)

  • save_each (int | None) – To save the linkage state (Default value = 0)

  • n_agents (int) – Number of agents (Default value = 300)

  • n_iterations (int) – NUmber of iterations (Default value = 400)

examples.strider.view_swarm_tiled(linkage, dimensions=(2, 0.7853981633974483, 1.8, 2.6, 1.4, 3.3415926535897933, 2.5, 1.8), save_each=0, n_agents=300, n_iterations=400)

Represent the final state of the best linkages.

Parameters:

  • linkage (Linkage) – Linkage to edit

  • dimensions (Sized) – Dimensions (Default value = DIMENSIONS)

  • save_each (int | None) – Period of state save (Default value = 0)

  • n_agents (int) – Number of agents (Default value = 300)

  • n_iterations (int) – NUmber of iterations (Default value = 400)

Module contents

This package feature some simple modules to demonstrate the capabilities of pylinkage.

Created on Sat Jun 26 17:29:26 2021.

@author: HugoFara.