Step 4.1: Yet another framework: APPLY

Yet an other WarpScript framework: APPLY! It’s a framework used to compute operation (like add, sub or mask) on multiple set of series. In this tutorial we will no enter in the details of this framework, but notice it exists and can but used to substract two set of series!

At the bottom of this page, you will find a practice example showing how to substract two set of time series.

The framework

The signature of the APPLY with a sub operator is described below. It takes 4 parameters: a set of time series that compose the minuend, an other set that compose the subtrahend of the sub operation. A list of labels and the op.sub operation are the last two required parameter.

This will compute the sub operation between the first and the second set (based on the equivalences classes).

Apply in pictures

To get a better understanding of the APPLY framework, let’s decompose the APPLY operation on several steps.

First several set of time series are needed as input. In our case, for the sub operation, a minuend is first needed:

Still in our case, a second set of time series is needed, the subtrahend:

After this operation an equivalence class have to be computed to split the series (in the example below) based on the record labels. This mean that we compute the APPLY operation only between the series of both set that belongs to the same equivalence class.

And finally, we select the apply operation to compute on each equivalence class:

In our case it would be the sub operation! Let’s practice it before applying this operation on the NASA lightcurve data.

Practice

The following example show you a quick demonstration on how to use it with the sub operator. In this example 4 time series are first created and put in two diffrent set. Then it’s up to you, hunter, to compute the difference of the earth or mars series of the first set with the one related contained in the second one! The base code is available in the APPLY skeleton below.

Pro-tips: Use the equivalence class on the label “name” to compute a name based difference

Resume

To compute a difference between two series, the framework APPLY need to be used. It’s also better to synchronize the ticks of each series using BUCKETIZE before computing this operation. The APPLY framework for the sub operation expects two set of list and an equivalence class. Where you careful when you set this parameter to be sure to compute a substraction on only the earth or mars series ?

As a result you get a list of two series: one containing all the value of the earth (resp. mars) rotation time series substracted of the value to correct of the second earth (resp. mars) time series.

To be continued

Once you are familiar with this specific operation of the APPLY framework, please continue with the next step, as you initiation as an exoplanet hunter is about to end. As a matter of fact, you now have the knowledge of all the needed tools to start exploring the kepler-11 start to detect it’s exoplanet.