Block methods and attributes

The Block object and its subclasses are key to bdsim.

Subclasses

Subclass	Purpose
SourceBlock	data source, outputs only
SinkBlock	data sink, inputs only, but not graphical
GraphicsBlock	data sink, inputs only, but graphical
FunctionBlock	instantaneous function of inputs, no state
TransferBlock	transfer function, has dynamics and state
SubsystemBlock	represents a subsystem and its connections
ClockedBlock	a discrete time block with states

Methods

Method name	Called when	Purpose
new	at construction	adds a reference to the owning block diagram
__init__	at construction	processes common arguments
add_outport	connecting	connect wire to block output port
add_inport	connecting	connect wire to block input port
start	simulation startup	initialise the block ready for simulation, report events
check	simulation startup	sanity check block parameters like number of inputs, outputs, states etc.
done	end of simulation	clean up, write files, matplotlib block etc.
step	every integrator time step	save output/state information
output	every integrator iteration	return output of the block based on time, inputs, state
setinput	every integrator iteration	set block port input value
setinputs	every integrator iteration	set all block port input values
__getitem__	diagram construction	create a plug by wire index or slice
__getattr__	diagram construction	create a plug from block port name
__setitem__	diagram construction	create a wire
__setattr__	diagram construction	create a wire
rshift	diagram construction	operator creates wire between operand blocks/plugs
_fixname	constructor	turn LaTeX port names to valid Python identifier name
inport_names	constructor	set block input port names
outport_names	constructor	set block output port names
state_names	constructor	set block state names, they are used in output object and plots
sourcename		Get the name of output port driving this input port
info		print information about the block
isclocked		true if the block is clocked

GraphicsBlock only

Method name	Called when	Purpose
savefig	end of simulation	GraphicsBlock only

TransferBlock and ClockedBlock only

Method name	Called when	Purpose
reset	start of simulation	copy initial state to current state
getstate0	start of simulation	return initial state vector
setstate	every integrator time step	set state vector

Attributes

Attribute name	Purpose
nin	number of input ports
nout	number of output ports
nstates	number of continuous-time states
ndstates	number of discrete-time states
id	unique sequential integer identifier, starts at 0
_clocked	bool, true if block is clocked
_input_names	list of names of input ports, includes LaTeX markup
_output_names	list of names of output ports, includes LaTeX markup
_state_names	list of names of states, includes LaTeX markup
inports	list(nin) of wires connected to input ports
outports	list(nout) of wires connected to output ports
_x	current state vector
_x0	initial state vector, set at construction time