pylinkage.linkage package

Submodules

pylinkage.linkage.analysis module

Analysis tools for linkages.

pylinkage.linkage.analysis.bounding_box(locus)

Compute the bounding box of a locus.

Parameters:: locus (list[tuple[float, float]] | tuple[tuple[float, float]]) – A list of points or any iterable with the same structure.
Returns:: Bounding box as (y_min, x_max, y_max, x_min).
Return type:: tuple[float, float, float, float]

pylinkage.linkage.analysis.kinematic_default_test(func, error_penalty)

Standard run for any linkage before a complete fitness evaluation.

This decorator makes a kinematic simulation, before passing the loci to the decorated function.

Parameters:

func (Callable) – Fitness function to be decorated.
error_penalty (float) – Penalty value for unbuildable linkage. Common values include float(‘inf’) and 0.

pylinkage.linkage.analysis.movement_bounding_box(loci)

Bounding box for a group of loci.

Parameters:: loci
Return type:: tuple[float, float, float, float]

pylinkage.linkage.linkage module

The linkage module defines useful classes for linkage definition.

Created on Fri Apr 16, 16:39:21 2021.

@author: HugoFara

class pylinkage.linkage.linkage.Linkage(joints, order=None, name=None)

Bases: object

A linkage is a set of Joint objects.

It is defined as a kinematic linkage. Coordinates are given relative to its own base.

get_coords(): Return the positions of each element in the system.

get_num_constraints(flat=True)

Numeric constraints of this linkage.

Parameters:: flat (bool) – Whether to force one-dimensional representation of constraints. The default is True.
Returns:: List of geometric constraints.
Return type:: list

get_rotation_period()

The number of iterations to finish in the previous state.

Formally, it is the common denominator of all crank periods.

Returns:: Number of iterations with dt=1.
Return type:: int

hyperstaticity(): Return the hyperstaticity (over-constrainment) degree of the linkage in 2D.

joints

name

rebuild(pos=None)

Redefine linkage joints and given initial positions to joints.

Parameters:: pos (tuple[tuple[int]]) – Initial positions for each joint in self.joints. Coordinates do not need to be precise, they will allow us the best fitting position between all possible positions satisfying constraints. (Default value = None)

set_completely(dimensions, positions, flat=True)

Set both dimension and initial positions.

Parameters:

dimensions (tuple[float] | tuple[tuple[float, float]]) – List of dimensions.
positions (tuple[tuple[float, float]]) – Initial positions
flat (bool) – If the dimensions are in “flat mode”. The default is True.

set_coords(coords)

Set coordinates for all joints of the linkage.

Parameters:: coords

set_num_constraints(constraints, flat=True)

Set numeric constraints for this linkage.

Numeric constraints are distances or angles between joints.

Parameters:

constraints (Iterable) – Sequence of constraints to pass to the joints.
flat (bool) – If True, constraints should be a one-dimensional sequence of floats. If False, constraints should be a sequence of tuples of digits. Each element will be passed to the set_constraints method of each corresponding Joint. (Default value = True)

step(iterations=None, dt=1)

Make a step of the linkage.

Parameters:

iterations (int) – Number of iterations to run across. If None, the default is self.get_rotation_period(). (Default value = None)
dt (float) – Amount of rotation to turn the cranks by. All cranks rotate by their self.angle * dt. The default is 1. (Default value = 1)

Returns:

Iterable of the joints’ coordinates.

Return type:

Generator[tuple[float, float]]

Module contents

Definition and analysis of a linkage as a dynamic set of joints.