d. Loops

The measurement states of an experiment are generated using loops. Loops are defined using lists, ranges, and expressions.

In our example, a range and an expression are used (see the Reference for more on Lists) in a loop to define the measurement states that the experiment will have.

A range is a compact way to specify a series of measurement states from a set of parameters.

In our example, the range will cause motorA to visit positions: 1.0, 2.0, 3.0, 4.0, and 5.0.   

An expression is a list of values for the trajectory to visit that is generated by a formula relying on lists, ranges, and other expressions.

In our example, the expression will cause motorB to visit positions: 2.0, 4.0, 6.0, 8.0, and 10.0. This is because motorA visits positions 1.0, 2.0, 3.0, 4.0, and 5.0 and motorB visits every position of motorA multiplied by two.

Note: Expressions should not be the only thing within a loop, because they depend on other values.  However, they can reference variables in outer loops - more on this later.