Configuring parameters¶
Edge Selection¶
There are different methods available to choose an input edge and output edge. To choose an input edge to pull an item from, the nodes utilises the strategy specified in the parameter in_edge_selection. Similarly, to select an output edge, to push the item to, nodes uses the method specified in out_edge_selection parameter. These parameters can be a constant integer value (one of the edge indices), or one of the methods available in the package (passed as a string; listed below) or a Python function or a generator function instance provided by the user. User-provided function should return or yield an edge index. If the function depends on any of the node attributes, users can pass None to these parameters at the time of node creation and later initialise the parameter with the reference to the function. Various options available in the package for in_edge_selection and out_edge_selection are listed below. To use these strategies, their names can be passed as a string while initialising the node.
- "RANDOM": Selects a random out edge.
- "ROUND_ROBIN": Selects out edges in a round-robin manner.
- "FIRST_AVAILABLE": Selects the first out edge that can accept an item.
In case of "FIRST_AVAILABLE", always the edge with the least index value will be selected if multiple edges are available. If blocking is set to False and out_edge_selection is set to "FIRST_AVAILABLE", then the worker thread will check if any of the out edges is available to accept. The item is discarded only if none of the edges are available.
Examples¶
- Example showing how to pass constant values to these parameters
- Example showing how to pass one of the methods available in the package as a string or a custom function to these parameters
Delay parameters¶
node_setup_time, inter_arrival_time and processing_delay are one of the two delay paramaters that can be configured. node_setup_time is an intial one time delay for setting up any node. inter_arrival_time is the time interval between two successive item generation in the source and processing_delay is the time incurres by an item to get processed in components like machine, split, joint, etc. node_setup_time can be an int or a float and is a constant value. The parameters inter_arrival_time and processing_delay can be specified as a constant value (int or float) or as a reference to a python function or a generator function instance that generates random variates from a chosen distribution. If the function depends on any of the node attributes, users can pass None to this parameter at the time of node creation and later initialise the parameter with the reference to the function.