Loops

Pulse provides the functionality to define and execute a loop. This feature allows the creation of iterative processes, whereby specific tasks can be repeated based on defined conditions, offering greater flexibility in automating repetitive tasks.

Building a Loop

You can define a loop over an entire workflow, or select just part of a workflow to loop. Defining a loop is very similar to defining a Sub-Process. You must ensure that the data transfer into and out of the loop are correct, like when defining a sub-process. There are two ways of creating a loop.

  • Use the Loop button on the Create ribbon to generate a loop block.

    Figure 1.

    Explode the loop block by double clicking on it. You can then build your workflow inside of the expanded loop.

    Figure 2.

  • From an already created workflow, select the modules and group them as part of a loop.

    Figure 3.
    The loop is then represented in the Study browser.
    Figure 4.

Setting Up a Loop

Loop parameters can be set through the Study browser.
Figure 5.
Name
Name of the loop.
Loop Type
Type of logical loop.
Variables
Inputs and outputs to/from the loop. Can be defined using the Variable browser inside of a loop.

While Loop

Condition
Logical condition to control the loop. It follows python syntax:
Example: [output] < [value] and ([input]:=[input] i+1)
The condition is set using Pulse process variables present inside the loop. See Process Variable for more information on how to create them. Best practice is to use process variables monitoring outputs to evaluate logical conditions, and increment process variables controlling inputs on each iteration. If no condition is set, Pulse will execute the loop through the number of maximum iterations defined by you.
Iteration Start
Step form which loop will start iterating.
Max Iteration
Maximum number of iterations.
Example
Figure 6.

In this example, the Pulse module calculates the volume of a cuboid based on length, height, and width inputs. The volume output is monitored by the Volume process variable, and the length input is controlled by Length process variable.

The loop condition is defined in the following way: v<280 and (l:=l+1)

This means that the module will be executed while its output (cuboid volume) is less than 280, and that after each iteration, length value will be increased by one.

The example above is a NO-CODE representation of the following Python loop:
Figure 7.
Loop Results
Loop results can be found in the current run folder. Each iteration folder will contain the output generated by the workflow defined inside the loop.
Figure 8.
Complex Example
Figure 9.
Logical conditions can also be applied to the incrementing/decrementing input variables. In this example, the input numbers of the sum are being modified. Variable a is incremented by one and variable b is decremented by one. Both have a logical condition applied to them.