Supporting classes

BDSim class

This class describes the run-time environment for executing a block diagram.

class bdsim.BDSim(banner=True, packages=None, load=True, toolboxes=True, **kwargs)

Bases: object

DEBUG(debug, fmt, *args)

__init__(banner=True, packages=None, load=True, toolboxes=True, **kwargs)

Parameters

• banner (bool, optional) – display docstring banner, defaults to True

• packages (str) – colon-separated list of folders to search for blocks

• load (bool,optional) – dynamically load blocks from libraries, defaults to True

• sysargs (bool, optional) – process options from sys.argv, defaults to True

• graphics (bool, optional) – enable graphics, defaults to True

• animation (bool, optional) – enable animation, defaults to False

• progress (bool, optional) – enable progress bar, defaults to True

• debug (str, optional) – debug options, defaults to None

• backend (str, optional) – matplotlib backend, defaults to ‘Qt5Agg’’

• tiles (str, optional) – figure tile layout on monitor, defaults to ‘3x4’

Raises

ImportError – syntax error in block

Returns

parent object for blockdiagram simulation

Return type

BDSim

If sysargs is True, process command line arguments and passed options. Command line arguments have precedence.

Command line switch	Argument	Default	Behaviour
–graphics, +g	graphics	True	enable graphical display
–animation, +a	animation	True	update graphics at each time step
–hold, +h	hold	True	hold graphics in done()
–no-graphics, -g	graphics	True	disable graphical display
–no-animation, -a	animation	True	don’t update graphics at each time step
–no-hold, -H	hold	True	do not hold graphics in done()
–no-progress, -p	progress	True	do not display simulation progress bar
–backend BE	backend	‘Qt5Agg’	matplotlib backend
–tiles RxC, -t RxC	tiles	‘3x4’	arrangement of figure tiles on the display
–shape WxH	shape	None	window size, default matplotlib size
–altscreen, +A,	altscreen	True	display plots on second monitor
–no-altscreen, -A	altscreen	True	do not display plots on second monitor
–debug F, -d F	debug	‘’	debug flag string
–simtime T[,dt]	simtime	(10,)	simulation time
–verbose, -v	verbose	False	be verbose
–quiet, -q	quiet	False	suppress reports
-o	outfile	None	output pickled simulation results to bd.out
–out OUTFILE	outfile	None	file to save pickled simulation results
–set P, -s P	setparam	[]	override block parameter using P=block:param=value
–global G	setglob	[]	override global parameter using G=var=value

Note

animation and graphics options are coupled. If graphics=False, all graphics is suppressed. If graphics=True then graphics are shown and the behaviour depends on animation. animation=False shows graphs at the end of the simulation, while ``animation=True` will animate the graphs during simulation.

Seealso

set_globals()

blockdiagram(name='main')

Instantiate a new block diagram object.

Parameters

name (str, optional) – diagram name, defaults to ‘main’

Returns

parent object for blockdiagram

Return type

BlockDiagram

This object describes the connectivity of a set of blocks and wires.

It is an instantiation of the BlockDiagram class with a factory method for every dynamically loaded block which returns an instance of the block. These factory methods have names which are all upper case, for example, the method .GAIN invokes the constructor for the Gain class.

Seealso

BlockDiagram()

blockinfo(block=None)

Return info about all blocks

Parameters

block (str, optional) – name of block to return info for, otherwise list of info for all

Returns

parameters of blocks

Return type

dict or list of dicts

Detailed metadata about a block is obtained by introspection and parsing the block’s docstring.

Key	Description
path	Path to the folder containing block definition
classname	Name of class
url	URL of online documentation
class	Reference to the class
module	Name of the module package.blocks.module
package	Name of the package, eg. bdsim, roboticstoolbox
params	Dict of (type, descrip), indexed by parameter name
inputs	List of names of block inputs
outputs	List of names of block outputs
nin	Number of inputs, -1 if variable
nout	Number of outputs, -1 if variable
blockclass	Block class, eg. source, sink etc.

blocks()

List all loaded blocks.

Example:

73  blocks loaded
bdsim.blocks.functions..................: Sum Prod Gain Clip Function Interpolate
bdsim.blocks.sources....................: Constant Time WaveForm Piecewise Step Ramp
bdsim.blocks.sinks......................: Print Stop Null Watch
bdsim.blocks.transfers..................: Integrator PoseIntegrator LTI_SS LTI_SISO
bdsim.blocks.discrete...................: ZOH DIntegrator DPoseIntegrator
bdsim.blocks.linalg.....................: Inverse Transpose Norm Flatten Slice2 Slice1 Det Cond
bdsim.blocks.displays...................: Scope ScopeXY ScopeXY1
bdsim.blocks.connections................: Item Dict Mux DeMux Index SubSystem InPort OutPort
roboticstoolbox.blocks.arm..............: FKine IKine Jacobian Tr2Delta Delta2Tr Point2Tr TR2T FDyn IDyn Gravload
........................................: Inertia Inertia_X FDyn_X ArmPlot Traj JTraj LSPB CTraj CirclePath
roboticstoolbox.blocks.mobile...........: Bicycle Unicycle DiffSteer VehiclePlot
roboticstoolbox.blocks.uav..............: MultiRotor MultiRotorMixer MultiRotorPlot
machinevisiontoolbox.blocks.camera......: Camera Visjac_p EstPose_p ImagePlane

closefigs()

done(bd, block=False)

fatal(message, retval=1)

Fatal simulation error

Parameters

• message (str) – Error message

• retval (int, optional) – system return value (*nix only) defaults to 1

Display the error message then terminate the process. For operating systems that support it, return an integer code.

load_blocks(verbose=True, toolboxes=True)

Dynamically load all block definitions.

Raises

ImportError – module could not be imported

Returns

dictionary of block metadata

Return type

dict of dict

Reads blocks from .py files found in bdsim/bdsim/blocks, folders given by colon separated list in envariable BDSIMPATH, and the command line option packages.

The result is a dict indexed by the upper-case block name with elements: - path to the folder holding the Python file defining the block - classname - blockname, upper case version of classname - url of online documentation for the block - package containing the block - doc is the docstring from the class constructor

report(bd, type='summary', **kwargs)

Print block diagram report

Parameters

• bd (BlockDiagram) – the block diagram to be reported

• type (str, optional) – report type, one of: “summary” (default), “lists”, “schedule”

• style (str) – table style, one of: ansi (default), markdown, latex

Single method wrapper for various block diagram reports. Obeys the -q option to suppress all reports at runtime.

Seealso

BlockDiagram.report_summary() BlockDiagram.report_lists() BlockDiagram.report_schedule()

run(bd, T=5, dt=None, solver='RK45', solver_args={}, debug='', block=None, checkfinite=True, minstepsize=1e-12, watch=[])

Run the block diagram

Parameters

• T (float, optional) – maximum integration time, defaults to 10.0

• dt (float, optional) – maximum time step

• solver (str, optional) – integration method, defaults to RK45

• block (bool) – matplotlib block at end of run, default False

• checkfinite (bool) – error if inf or nan on any wire, default True

• minstepsize (float) – minimum step length, default 1e-6

• watch (list) – list of input ports to log

• solver_args (dict) – arguments passed to scipy.integrate

Returns

time history of signals and states

Return type

Sim class

Assumes that the network has been compiled.

The system is simulated from time 0 to T.

The integration step time dt defaults to T/100 but can be specified. Finer control can be achieved using max_step and first_step parameters to the underlying integrator using the solver_args parameter.

Results are returned in a class with attributes:

• t the time vector: ndarray, shape=(M,)

• x is the state vector: ndarray, shape=(M,N)

• xnames is a list of the names of the states corresponding to columns of x, eg. “plant.x0”,

  defined for the block using the snames argument

• yN for a watched input where N is the index of the port mentioned in the watch argument

• ynames is a list of the names of the input ports being watched, same order as in watch argument

If there are no dynamic elements in the diagram, ie. no states, then x and xnames are not present.

The watch argument is a list of one or more input ports whose value during simulation will be recorded. The elements of the list can be:

• a Block reference, which is interpretted as input port 0

• a Plug reference, ie. a block with an index or attribute

• a string of the form “block[i]” which is port i of the block named block.

The debug string comprises single letter flags:

• ‘p’ debug network value propagation

• ‘s’ debug state vector

• ‘d’ debug state derivative

Note

Simulation stops if the step time falls below minsteplength which typically indicates that the solver is struggling with a very harsh non-linearity.

run_interval(bd, t0, T, x0, simstate=None)

Integrate system over interval

Parameters

• bd (BlockDiagram) – the system blockdiagram

• t0 (float) – initial time

• tf (float) – final time

• x0 (ndarray(n)) – initial state vector

• simstate (SimState) – simulation state object

Returns

final state vector xf

Return type

ndarray(n)

The system is integrated from from x0 to xf over the interval t0 to tf.

savefig(block, filename=None, format='pdf', **kwargs)

savefigs(bd, format='pdf', **kwargs)

set_globals(globs)

Set globals as specified by command line

Parameters

globs (dict) – global variables

The command line option --global var=value can be used to request the change of global variables. However, actually changing them requires explicit code support in the user’s program after the BDSim constructor.

Example:

sim.set_globals(globals())

Messages are displayed by defaulting, indicating which variables are changed, and their old and new values.

set_options(**options)

showgraph(bd, **kwargs)

update_parameters(bd)

Set value of parameters according to command line arguments

Command line arguments of the form:

-s block:param=value --set block:param=value

are stored as list items in options.setparam

block can be either:

• the block’s name as a string, either user assigned or bdsim assigned

• the block id as displayed by the report method

param is the name of the parameter used in the constructor

value is the new value of the variable

class bdsim.BDSimState

Bases: object

Variables

• x (np.ndarray) – state vector

• T (float) – maximum simulation time (seconds)

• t (float) – current simulation time (seconds)

• fignum (int) – number of next matplotlib figure to create

• stop (Block subclass) – reference to block wanting to stop simulation, else None

• checkfinite (bool) – halt simulation if any wire has inf or nan

• graphics (bool) – enable graphics

__init__()

declare_event(block, t)

BlockDiagram class

This class describes a block diagram, a collection of blocks and wires that can be “executed”.

class bdsim.BlockDiagram(name='main', **kwargs)

Bases: object

Block diagram class. This object is the parent of all blocks and wires in the system.

Variables

• wirelist (list of Wire instances) – all wires in the diagram

• blocklist (list of Block subclass instances) – all blocks in the diagram

• x (np.ndarray) – state vector

• compiled (bool) – diagram has successfully compiled

• blockcounter (collections.Counter) – unique counter for each block type

• blockdict (dict of lists) – index of all blocks by category

• name (str) – name of this diagram

This object:

• holds all the blocks and wires that comprise the system

• manages continuous- and discrete-time state vector for the whole system, splitting it across blocks as required

• evaluates the entire diagram as a function to compute dot{x} = f(x, t)()

add_block(block)

add_wire(wire, name=None)

blockvalues(t=None, simstate=None)

clock(*args, **kwargs)

compile(subsystem=False, doimport=True, evaluate=True, report=False, verbose=True)

Compile the block diagram

Parameters

• subsystem (bool, optional) – importing a subsystems, defaults to False

• doimport (bool, optional) – import subsystems, defaults to True

Raises

RuntimeError – various block diagram errors

Returns

Compile status

Return type

bool

Performs a number of operations:

• Check sanity of block parameters

• Recursively clone and import subsystems

• Check for loops without dynamics

• Check for inputs driven by more than one wire

• Check for unconnected inputs and outputs

• Link all output ports to outgoing wires

• Link all input ports to incoming wires

• Evaluate all blocks in the network

connect(start, *ends, name=None)

TODO:

s.connect(out[3], in1[2], in2[3]) # one to many block[1] = SigGen() # use setitem block[1] = SumJunction(block2[3], block3[4]) * Gain(value=2)

deriv(t)

Harvest derivatives from all blocks.

Parameters

• t (float) – simulation time, defaults to None

• simstate (SimState, optional) – simulation state, defaults to None

done(block=False)

Finishup all blocks

Parameters

• state (SimState, optional) – simulation state, defaults to None

• graphics (bool, optional) – graphics enabled, defaults to False

Inform all blocks that BlockDiagram execution is complete by invoking their done method and passing options. Used to close files, display figures etc.

Note

if graphics is False, Graphics blocks are not called

dotfile(filename, shapes=None)

Write a GraphViz dot file representing the network.

Parameters

• file (str, file handle) – Name of file to write to, or file handle

• shapes (dict) – block shapes

Create a GraphViz format file for procesing by dot. The graph is:

• directed graph, drawn left to right

• source blocks are in the first column

• sink and graphics blocks are in the last column

• SUM and PROD blocks have the sign or operation of their input wires labeled.

The file can be processed using dot:

% dot -Tpng -o out.png dotfile.dot

Note

By default all blocks have the default shape, with source blocks shown as a rectangle (“record”), and sink/graphics blocks as a rounded rectangle (“Mrecord”). This can be overriden by provide a dictionary shapes that maps block class (sink, source, graphics, function, transfer) to the names of GraphViz shapes.

Seealso

showgraph()

getstate0()

initialstate()

property issubsystem

ls()

report(**kwargs)

report_lists(**kwargs)

Print a tabular report about the block diagram.

Parameters

kwargs – options passed to ansitable.ANSITable.print()

Print the important lists in pretty format.

• block list, all blocks

• wire list, all wires

• clock list, all discrete time clocks

report_schedule(**kwargs)

Display execution schedule in tabular form

Parameters

kwargs – options passed to ansitable.ANSITable.print()

Seealso

schedule_plan(), schedule_dotfile()

report_summary(sortby='name', **kwargs)

Print a summary of block diagram.

Parameters

• sortby (str, optional) – sort rows by specified block attribute: “name” [default] or “type”

• style (str) – table style, one of: ansi (default), markdown, latex

Print a table with 4 columns:

1. Block name, sorted in alphabetical order

2. The input port (if not a source block)

3. The block driving this port (if not a source block)

4. The type of value driving this port (if not a source block)

If the block is an event source, add a @ suffix.

reset()

Reset conditions within every active block. Most importantly, all inputs are marked as unknown.

Invokes the reset method on all blocks.

schedule_dotfile(filename)

Write a GraphViz dot file representing the execution schedule

Parameters

file (str) – Name of file to write to

The file can be processed using neato or dot:

% dot -Tpng -o out.png dotfile.dot

Display execution plan as a dataflow graph.

Seealso

schedule_plan(), schedule_print()

schedule_evaluate(x, t, checkfinite=True, sinks=True, simstate=None)

Evaluate all blocks in the network

Parameters

• x (ndarray) – state

• t (float) – current time

• checkfinite (bool) – check for Inf or Nan values in block outputs

• sinks (bool, optional) – evaluate sink blocks, defaults to Trye

• simstate – simulation state

Returns

state derivative

Return type

numpy.ndarray

Performs the following steps:

1. Partition the state vector x to all stateful blocks

2. Execute the blocks in the order given by the plan. The block outputs are “sent” to their connected inputs.

Sink blocks are not executed here, but after completion their inputs will all be valid.

schedule_generate()

Create execution plan

The plan is saved in the attribute plan and is a list [L0, L1, ... LN] where each Li is a list of blocks. The blocks in the lists are executed sequentially, ie. all the blocks in L0 then all the blocks in L1 etc.

The plan ensures that the inputs of all blocks in Li have been previously computed.

Note

• The plan is essentially a dataflow graph.

• The blocks in list Li could potentially be executed in parallel.

• Constant blocks and stateful blocks are all executed in L0

• The block attribute _sequence is i and indicates its execution order

Seealso

schedule_report(), schedule_dotfile()

showgraph()

Display diagram as a graph in browser tab

Seealso

dotfile()

start(simstate=None)

Start all blocks

Parameters

simstate (SimState, optional) – simulation state, defaults to None

Inform all blocks that BlockDiagram execution is about to start by invoking their start method and passing the state object. Used to open files, create figures etc.

Note

if graphics is False, Graphics blocks are not called

step(t)

Step all blocks

Parameters

• t (float) – simulation time, defaults to None

• inports (list) – block input port values

Tell all blocks to take action on new inputs by invoking their step method and passing the state object. Used to save results to a figure or file.

Called at the end of every integration interval.

Note

• if graphics is False, Graphics blocks are not called

Components

Wire

class bdsim.Wire(start=None, end=None, name=None)

Bases: object

Create a wire.

Parameters

• start (Plug, optional) – Plug at the start of a wire, defaults to None

• end (Plug, optional) – Plug at the end of a wire, defaults to None

• name (str, optional) – Name of wire, defaults to None

Returns

A wire object

Return type

Wire

A Wire object connects two block ports. A Wire has a reference to the start and end ports.

A wire records all the connections defined by the user. At compile time wires are used to build inter-block references.

Between two blocks, a wire can connect one or more ports, ie. it can connect a set of output ports on one block to a same sized set of input ports on another block.

property fullname

Display wire connection details.

Returns

Wire name

Return type

str

String format:

d2goal[0] --> Kv[0]

property info

Interactive display of wire properties.

Displays all attributes of the wire for debugging purposes.

Plug

class bdsim.Plug(block, port=0, type=None)

Bases: object

Create a plug.

Parameters

• block (Block) – The block being plugged into

• port (int, optional) – The port on the block, defaults to 0

• type (str, optional) – ‘start’ or ‘end’, defaults to None

Returns

Plug object

Return type

Plug

Plugs are the interface between a wire and block and have information about port number and wire end. Plugs are on the end of each wire, and connect a Wire to a specific port on a Block.

The type argument indicates if the Plug is at:

• the start of a wire, ie. the port is an output port

• the end of a wire, ie. the port is an input port

A plug can specify a set of ports on a block.

__add__(**kwargs)

__getitem__(i)

__init__(block, port=0, type=None)

__mul__(**kwargs)

__neg__(**kwargs)

__pow__(**kwargs)

__radd__(**kwargs)

__repr__()

Display plug details.

Returns

Plug description

Return type

str

String format:

bicycle.0[1]

__rmul__(**kwargs)

__rshift__(**kwargs)

__rsub__(**kwargs)

__rtruediv__(**kwargs)

__str__()

Display plug details.

Returns

Plug description

Return type

str

String format:

bicycle.0[1]

__sub__(**kwargs)

__truediv__(**kwargs)

property isslice

Test if port number is a slice.

Returns

Whether the port is a slice

Return type

bool

Returns True if the port is a slice, eg. [0:3], and False for a simple index, eg. [2].

property portlist

Return port numbers.

Returns

Port numbers

Return type

iterable of int

If the port is a simple index, eg. [2] returns [2].

If the port is a slice, eg. [0:3], returns [0, 1, 2]. For the case [2:] the upper bound is the maximum number of input or output ports of the block.

property width

Return number of ports connected.

Returns

Number of ports

Return type

int

If the port is a simple index, eg. [2] returns 1.

If the port is a slice, eg. [0:3], returns 3.

Blocks

class bdsim.Block(*args, bd=None, **kwargs)

Bases: object

T_deriv(*inputs, t=0.0, x=None)

Evaluate a block for unit testing.

Parameters

• inputs (list) – input port values

• t (float, optional) – Simulation time, defaults to 0.0

• x (ndarray) – state vector

Returns

Block derivative value

Return type

ndarray

The derivative of the block is evaluated for a given set of input port values. Input port values are treated as lists.

Mostly used for making concise unit tests.

Warning

the instance is monkey patched, not useable in a block diagram subsequently.

T_next(*inputs, t=0.0, x=None)

Evaluate a block for unit testing.

Parameters

• inputs (list) – input port values

• t (float, optional) – Simulation time, defaults to 0.0

• x (ndarray) – state vector

Returns

Block next state value

Return type

ndarray

The next value of a discrete time block is evaluated for a given set of input port values. Input port values are treated as lists.

Mostly used for making concise unit tests.

T_output(*inputs, t=0.0, x=None)

Evaluate a block for unit testing.

Parameters

• *inputs –

  Input port values

• t (float, optional) – Simulation time, defaults to 0.0

• x (ndarray) – state vector

Returns

Block output port values

Return type

list

The output ports of the block are evaluated for a given simulation time and set of input port values. Input ports are assigned to consecutive inputs, output port values are a list.

Mostly used for making concise unit tests.

Warning

the instance is monkey patched, not useable in a block diagram subsequently.

T_start(simstate=None)

T_step(*inputs, t=0.0)

Step a block for unit testing.

Parameters

• inputs (list) – input port values

• t (float, optional) – Simulation time, defaults to 0.0

Step the block for a given set of input port values. Input port values are treated as lists.

Mostly used for making concise unit tests.

__add__(**kwargs)

__getitem__(port)

Convert a block slice reference to a plug.

Parameters

port (int) – Port number

Returns

A port plug

Return type

Plug

Invoked whenever a block is referenced as a slice, for example:

c = bd.CONSTANT(1)

bd.connect(x, c[0])
bd.connect(c[0], x)

In both cases c[0] is converted to a Plug by this method.

__init__(name=None, nin=None, nout=None, inputs=None, type=None, inames=None, onames=None, snames=None, pos=None, bd=None, blockclass=None, verbose=False, **kwargs)

Construct a new block object.

Parameters

• name (str, optional) – Name of the block, defaults to None

• nin (int, optional) – Number of inputs, defaults to None

• nout (int, optional) – Number of outputs, defaults to None

• inputs (Block, Plug or list of Block or Plug) – Optional incoming connections

• inames (list of str, optional) – Names of input ports, defaults to None

• onames (list of str, optional) – Names of output ports, defaults to None

• snames (list of str, optional) – Names of states, defaults to None

• pos (2-element tuple or list, optional) – Position of block on the canvas, defaults to None

• bd (BlockDiagram, optional) – Parent block diagram, defaults to None

• verbose (bool, optional) – enable diagnostic prints, defaults to False

• kwargs (dict) – Unused arguments

Returns

A Block superclass

Return type

Block

A block object is the superclass of all blocks in the simulation environment.

This is the top-level initializer, and handles most options passed to the superclass initializer for each block in the library.

__mul__(**kwargs)

__neg__(**kwargs)

static __new__(cls, *args, bd=None, **kwargs)

Construct a new Block object.

Parameters

• cls (class type) – The class to construct

• *args –

  positional args passed to constructor

• **kwargs –

  keyword args passed to constructor

Returns

new Block instance

Return type

Block instance

__pow__(**kwargs)

__radd__(**kwargs)

__repr__()

Return repr(self).

__rmul__(**kwargs)

__rshift__(**kwargs)

__rsub__(**kwargs)

__rtruediv__(**kwargs)

__setattr__(name, value)

Convert a LHS block name reference to a wire.

Parameters

• name – Port name

• value (Block or Plug) – the RHS

Used to create a wired connection by assignment, for example:

c = bd.CONSTANT(1, inames=['u'])

c.u = x

Ths method is invoked to create a wire from x to port ‘u’ of the constant block c.

Notes:

• this overloaded method handles all instances of setattr and implements normal functionality as well, only creating a wire if name is a known port name.

__setitem__(port, src)

Convert a LHS block slice reference to a wire.

Parameters

• port (int) – Port number

• src (Block or Plug) – the RHS

Used to create a wired connection by assignment, for example:

X[0] = Y

where X and Y are blocks. This method is implicitly invoked and creates a wire from Y to input port 0 of X.

Note

The square brackets on the left-hand-side is critical, and X = Y will simply overwrite the reference to X.

__str__()

Return str(self).

__sub__(**kwargs)

__truediv__(**kwargs)

add_input_wire(w)

add_output_wire(w)

add_param(param, handler=None)

check()

done(**kwargs)

property info

Interactive display of block properties.

Displays all attributes of the block for debugging purposes.

inport_names(names)

Set the names of block input ports.

Parameters

names (list of str) – List of port names

Invoked by the inames argument to the Block constructor.

The names can include LaTeX math markup. The LaTeX version is used where appropriate, but the port names are a de-LaTeXd version of the given string with backslash, caret, braces and dollar signs removed.

property inputs

Get block inputs as a list

Returns

list of block inputs

Return type

list

Returns a list of values corresponding to the input ports of the block. The types of the elements are dictated by the blocks connected to the input ports.

Note

When a block’s output method is evaluated the resulting list is saved as an attribute of that block. The inputs method uses the sources attribute which has references to the output values held by the predecessor block.

Seealso

input()

property isclocked

Test if block is clocked

Returns

True if block is clocked

Return type

bool

True if block is clocked, False if it is continuous time.

property isgraphics

Test if block does graphics

Returns

True if block does graphics

Return type

bool

outport_names(names)

Set the names of block output ports.

Parameters

names (list of str) – List of port names

Invoked by the onames argument to the Block constructor.

The names can include LaTeX math markup. The LaTeX version is used where appropriate, but the port names are a de-LaTeXd version of the given string with backslash, caret, braces and dollar signs removed.

reset()

savefig(*pos, **kwargs)

set_param(name, newvalue)

sourcename(port)

Get the name of output port driving this input port.

Parameters

port (int) – Input port

Returns

Port name

Return type

str

Return the name of the output port that drives the specified input port. The name can be:

• a LaTeX string if provided

• block name with port number given in square brackets. The block name will the one optionally assigned by the user using the name keyword, otherwise a systematic default name.

Seealso

outport_names

start(simstate)

state_names(names)

varinputs = False

varoutputs = False

Source block

class bdsim.SourceBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.Block

A SourceBlock is a subclass of Block that represents a block that has outputs but no inputs. Its output is a function of parameters and time.

__init__(**blockargs)

Create a source block.

Parameters

blockargs (dict) – common Block options

Returns

source block base class

Return type

SourceBlock

This is the parent class of all source blocks.

__module__ = 'bdsim.components'

blockclass = 'source'

Sink block

class bdsim.SinkBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.Block

A SinkBlock is a subclass of Block that represents a block that has inputs but no outputs. Typically used to save data to a variable, file or graphics.

__init__(**blockargs)

Create a sink block.

Parameters

blockargs (dict) – common Block options

Returns

sink block base class

Return type

SinkBlock

This is the parent class of all sink blocks.

__module__ = 'bdsim.components'

blockclass = 'sink'

step(t, inports)

Function block

class bdsim.FunctionBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.Block

A FunctionBlock is a subclass of Block that represents a block that has inputs and outputs but no state variables. Typically used to describe operations such as gain, summation or various mappings.

__init__(**blockargs)

Create a function block.

Parameters

blockargs (dict) – common Block options

Returns

function block base class

Return type

FunctionBlock

This is the parent class of all function blocks.

__module__ = 'bdsim.components'

blockclass = 'function'

Transfer function block

class bdsim.TransferBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.Block

A TransferBlock is a subclass of Block that represents a block with inputs outputs and states. Typically used to describe a continuous time dynamic system, either linear or nonlinear.

__init__(nstates=1, **blockargs)

Create a transfer function block.

Parameters

blockargs (dict) – common Block options

Returns

transfer function block base class

Return type

TransferBlock

This is the parent class of all transfer function blocks.

__module__ = 'bdsim.components'

blockclass = 'transfer'

check()

getstate0()

reset()

setstate(x)

Subsystem block

class bdsim.SubsystemBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.Block

A SubSystem s a subclass of Block that represents a block that has inputs and outputs but no state variables. Typically used to describe operations such as gain, summation or various mappings.

__init__(**blockargs)

Create a subsystem block.

Parameters

blockargs (dict) – common Block options

Returns

subsystem block base class

Return type

SubsystemBlock

This is the parent class of all subsystem blocks.

__module__ = 'bdsim.components'

blockclass = 'subsystem'

Graphics block

class bdsim.GraphicsBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.SinkBlock

A GraphicsBlock is a subclass of SinkBlock that represents a block that has inputs but no outputs and creates/updates a graphical display.

__init__(movie=None, **blockargs)

Create a graphical display block.

Parameters

• movie (str, optional) – Save animation in this file in MP4 format, defaults to None

• blockargs (dict) – common Block options

Returns

transfer function block base class

Return type

TransferBlock

This is the parent class of all graphic display blocks.

__module__ = 'bdsim.graphics'

blockclass = 'graphics'

create_figure(state)

done(block=False)

savefig(filename=None, format='pdf', **kwargs)

Save the figure as an image file

Parameters

• fname (str) – Name of file to save graphics to

• **kwargs – Options passed to savefig

The file format is taken from the file extension and can be jpeg, png or pdf.

start(simstate)

step(t, inports)

Discrete-time systems

class bdsim.ClockedBlock(*args, bd=None, **kwargs)

Bases: bdsim.components.Block

A ClockedBlock is a subclass of Block that represents a block with inputs outputs and discrete states. Typically used to describe a discrete time dynamic system, either linear or nonlinear.

__init__(clock=None, **blockargs)

Create a clocked block.

Parameters

blockargs (dict) – common Block options

Returns

clocked block base class

Return type

ClockedBlock

This is the parent class of all clocked blocks.

blockclass = 'clocked'

check()

getstate0()

reset()

setstate(x)

class bdsim.Clock(arg, unit='s', offset=0, name=None)

Bases: object

__init__(arg, unit='s', offset=0, name=None)

add_block(block)

getstate(t)

getstate0()

next_event(simstate=None)

savestate(t)

setstate()

start(simstate=None)

time(i)