Systems package

Package Systems

This module contains all the system types that are provided by pyHarm. The module is organized around an abstract class ABCSystem and a FactorySystem that is in charge of instantiating the objects. All system objects must comply with the ABCSystem abstract class. The section below presents the different modules that are available.

ABCSystem

The ABCSystem class is an abstract class defining the essential components of any system. Two abstract methods are mandatory :

Methods	Use
Residual	Abstract method : Returns residual of all the elements
Jacobian	Abstract method : Returns jacobian of all the elements

Examples of creating an ABCSystem and adding it into an input dictionary:

To be created, an ABCSystem needs at least a Substructure but many substructures can be defined in the input file. Connectors and kinematic conditions can be added to the problem to complete the system to be solved. The integration in an input file would look like :

class FakeSystem(ABCSystem):
    factory_keyword="fakesystem"
    def Residual(q:np.ndarray)->np.ndarray:
        # Codes how to assemble residuals
        return Residual_vector
    def Jacobian(q:np.ndarray)->tuple(np.ndarray,np.ndarray):
        # Codes how to assemble jacobians
        return dRdx, dRdom

INP = {
    ...,
    "system":{
        "type":FakeSystem.factory_keyword,
        ...,
    },
    "substructures":{
        "sub_1":{ # At least the definition of 1 substructure is mandatory
            ...,
        },
        ...,
    },
    "connectors":{
        "connector_1":{
            ...
        },
        ...
    },
    "kinematics":{
        "kine_1":{
            ...
        },
        ...,
    }
}

FactorySystem

This file contains the dictionary of all the systems that are available as well as the function generateSystem that creates the ABCSystem object. The System_dico attribute defined in this module gathers all the ABCSystem subclasses that are available for creation.

System Base

Basic system class that implements the computation of Residual and Jacobian methods by chaining _residual and _jacobian methods onto the different lists of elements.

The parameters associated with the system creation are the following :

Parameter	Use	Default
nh	number of harmonics to be considered [int | list[int]]	✓ : 1
nti	number of time instant used in the AFT procedure [int]	✓ : 128
adim	Parameters used for adimensionalising the system [dict[bool,float,float]]	✓ : {“status”:False, “lc”:1.0, “wc”:1.0}

The harmonic number can also be provided as a list of integer. Allowing user to choose specfic harmonics to be solved (e.g. [1, 3, 5, 7]).

Examples of creating a Base system:

INP = {
    ...,
    "system":{
        "type":"Base",
        "nh":3,
        "nti":128,
        "adim":{
            "status":True,
            "lc":3.14,
            "wc":1.618e+02
        }
    },
    "substructures":{
        ...,
    }
    ...,
}

API links

pyHarm.Systems