Switch node is a kind of Control node. In fact two
nodes present Switch: start Switch and end Switch. Nodes of such type
are always InLine nodes. You have to supply this type of node by service,
which will perform switching. That's why nodes of such type can have at
least two or more switch ports (Boolean), but only one switch port can
have "True" value at a definite moment of graph execution. With
that kind of node you can define all kinds of tests or switches :
“if( condition ) ; else if( condition ) … ; else” or
“switch( variable ) ; case value …; default”.
Etc…
Titles of the nodes. By default the name of the service is used. You can change only the name of the Start Switch node - the name of the End Switch node will be automatically created as follows: EndOf + "Name of the Start Switch node" .
Status of execution shows state of the loop. It can be: Not Started, Running, Finished.
InGate/OutGate - control ports of the loop execution.
SwitchPort – ports for control management of the Switch. The values in this ports are of boolean type and can be 0 or 1. They must be connected to InGate ports of the correspondent computation nodes.
Input/Output ports – Input port of the Start Switch node will get the initial value, which can be processed by underlying Python function and will be transferred inside of the switch. The last computation node of the switch will put this value to the input port of the End Switch node.
The associated Python function will have all input ports of the Switch node as input arguments. And that function must return a value for all output ports. A simple example of this Python function:
def Switch(x):
i1=0
i2=0
i3=0
if x>13:
i1=1
elif x==13:
i2=1
else:
i3=1
return i1,i2,i3
In this example i1, i2, i3 parameters of the function correspond to Switch ports of the node. So, depending on the result of execution of the initial condition (in our case it's a comparison of the input parameter with an integer 13), one of the switch ports will get the value 1. And this port will transmit further dataflow to the corresponding node.
Switch nodes have the following particularities:
You must define at first boolean output ports which correspond to cases of the switch. They must be connected to Input Gates of head nodes of each branch of switch.
A branch of condition may begin with one or some nodes if there is parallelism of execution of nodes.
During execution of the Switch there can be one and only one such boolean output port with a “true” value.
The input ports created by the user in an End Switch node are automatically duplicated by the SuperVision component as output ports of the End Switch node. That component will fill the value of such output ports with the corresponding values of such input ports at execution time.
Each branch of the switch must have links to all input ports of the End Switch node.
But at execution time, there will be only one branch executed.
The end of branch of a switch may have one or some nodes if there is parallelism of execution of nodes.
