Custom factors in Synthace are factors that do not map to a specific parameters within an element, but are still variables that you want to investigate as part of your DOE.

For example, you might want to investigate the effect of temperature in your biological system, and to include this as part of your design, even though it does not map directly to an element parameter and is not a variable that Synthace can control.

In this tutorial you will learn:

Where to add a custom factor,
How to define the custom factor type,
How to set a custom continuous factor as a Quasi-Replicate,
How to set a custom continuous factor as Hard To Change,
How to set a custom continuous factor to sample discretely, or a range of values,
How to define runs that have the factor set to zero.

Defining a custom numerical factor

Adding a new custom numerical factor.

Build a workflow that defines a set of liquids and provides those liquids to a Make Mixtures element.
Switch the workflow builder into DOE Mode.

Note: only the elements that can have DOE factors applied to their parameters will be interactive and display in colour. If the workflow has not already been added to a Synthace experiment you will be prompted to do so before being able to enter DOE mode.
Click the Design button to launch the Factors Table.

Note: Even if there are no factors defined, clicking the Design button will launch the Factors Table. If other factors are already defined, then clicking on the Design button will launch the design calculation panel. In this case, to get to the Factors Table, click the Design button and navigate to the Factors Table by clicking “Factors” at the top of the panel. Alternatively, click a DOE supported element in your workflow, and launch the Factors table by clicking any of the factor buttons in the instance panel.
Click the “ADD” button in the Custom Factors section to select a factor type.
Select the “New Factor” Option to open the Factor Definition Panel.

Defining factor properties

Set your custom factor name

Unlike DOE factors that directly map to Synthace element parameters, the names of custom factors are not auto-suggested.

You must provide a factor name for your custom factor. This name will be used to identify this factor and its settings all the way through to your analysis, so be sure to pick a name that is descriptive of the factor (in this example, Temperature).

Setting Factor Properties

Select whether your custom factor is Numerical or Categorical. In this example, Temperature is a continuous numerical factor.
Specify the units for this factor.

Note: Custom factors can take any units you specify in the free text field. You can also define factors that have no units at all, like pH, for example.
Define the levels you want to investigate for your factor. Click the “Add New Item” button to add additional levels.
To treat this factor as a Quasi-Replicate, tick the check box. To learn more about Quasi-replicating factors, see here.

Note: making a factor a quasi-replicate will disable the sampling control panel, as all quasi replicate factors are sampled discretely at the levels that were defined above.
To treat this factor as Hard To Change, tick the check box. To learn more about Hard to Change factors see here.

Note: making a factor Hard to Change will disable the sampling control panel, as all hard to change factors are sampled discretely at the levels that were defined above.
If you intend to use a space-filling design in your experiment, choose whether you want to sample your defined levels discretely or across a range.

Note: if sampling across a range, when calculating a space filling design, only the lowest and highest levels defined will be considered. Any intermediate levels defined will be disregarded. Be aware that, when it comes to custom factors, you, as a user, have to set these up. Therefore, it is advised to treat these custom factors discretely, so that they can be feasibly handled manually.
When sampling across a range, for space filling designs, you can also define how many runs you would like to have this factor sampled at a zero set point.
Click “Add Factor” to save the factor to your Factor Table, where you will see a summary of the factors settings.