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Category: R

Basics Of R Plotting

Published 2017-04-12 by Kevin Feasel

Aman Tsegai shows some basic ways to customize R’s plot function:

We’re going to be using the cars dataset that is built in R. To follow along with real code, here’s an interactive R Notebook. Feel free to copy it and play around with the code as you read along.

So if we were to simply plot the dataset using just the data as the only parameter, it’d look like this:

plot(dataset)

The plot function is great for cases where you don’t much care how the visual looks, and the simplicity is great for throwaway visuals.

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R Plots In Power BI

Published 2017-04-11 by Kevin Feasel

Leila Etaati has a three-part series on displaying R visuals in Power BI.  Part 1 shows how to create a scatter plot:

so in the above picture we can see that we have 3 different fields that has been shown in the chart :highway and city speed in y and x axis. while the car’s cylinder varibale has been shown as different cycle size. However may be you need a bigger cycle to differentiate cylinder with 8 to 4 so we able to do that with add another layer by adding a function name

Part 2 shows how to use facet_grid to show multiple plots in one visual:

now I want to add other layer to this chart. by adding year and car drive option to the chart. To do that first choose year and drv  from data field in power BI. As I have mentioned before, now the dataset variable will  hold data about speed in city, speed in highway, number of cylinder, years of cars and type of drive.

I am going to use another function in the ggplot packages name “facet_grid” that helps me to show the different facet in my scatter chart. in this function, year and drv (driver) will be shown against each other.

Part 3 shows how to place charts on a map in R:

Now I have to merg the data to get the location information from “sPDF” into “ddf”. To do that I am going to use” merge” function. As you can see in below code, first argument is our first dataset “ddf” and the second one is the data on Lat and Lon of location (sPDF). the third and forth columns show the main variables for joining these two dataset as “ddf” (x) is “country” and in the second one “sPDF”  is “Admin”. the result will be stored in “df” dataset

Aside from my strong dislike of bar/pie charts on maps, this is good to know, particularly if there is not a built-in or customer Power BI visual to replicate something you can do in R.

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Logging R Scripts

Published 2017-04-11 by Kevin Feasel

Tomaz Kastrun shows the places where you might be able to track R scripts running on your system:

Extensibility Log will store information about the session but it will not store the R or R environment information or data, just session information and data. Navigate to:

C:\Program Files\Microsoft SQL Server\MSSQL13.MSSQLSERVER\MSSQL\LOG\ExtensibilityLog

to check the content and to see, if there is anything useful for your needs.

It’s not a great answer today.

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Microsoft R Open 3.3.3

Published 2017-04-07 by Kevin Feasel

David Smith reports that Microsoft R Open 3.3.3 is now available:

Microsoft R Open (MRO), Microsoft’s enhanced distribution of open source R, has been upgraded to version 3.3.3, and is now available for download for Windows, Mac, and Linux. This update upgrades the R language engine to R 3.3.3, upgrades the installer, and updates the bundled packages.

R 3.3.3 makes just a few minor fixes compared to R 3.3.2 (see the full list of changes here), so you shouldn’t encounter any compatibility issues when upgrading from MRO 3.3.2. For CRAN packages, MRO 3.3.3 points to CRAN snapshot taken on March 15, 2017 but as always, you can use the built-in checkpoint package to access packages from an earlier date (for compatibility) or a later date (to access new and updated packages).

Click through for more details.  As a side note, CRAN R 3.4 is scheduled for release this month, so given their recent cadence, I’d guess MRO 3.4 to be out late this year.

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Using OLS To Fit Rational Functions

Published 2017-04-06 by Kevin Feasel

Srini Kumar and Bob Horton show how to use the lm function to fit functions using the Pade Approximation:

Now we have a form that lm can work with. We just need to specify a set of inputs that are powers of x (as in a traditional polynomial fit), and a set of inputs that are y times powers of x. This may seem like a strange thing to do, because we are making a model where we would need to know the value of y in order to predict y. But the trick here is that we will not try to use the fitted model to predict anything; we will just take the coefficients out and rearrange them in a function. The fit_pade function below takes a dataframe with x and y values, fits an lm model, and returns a function of x that uses the coefficents from the model to predict y:

The lm function does more than just fit straight lines.

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New RTVS Instructions

Published 2017-04-06 by Kevin Feasel

Ginger Grant has updated her instructions for installing R Tools for Visual Studio and getting R Services to work on SQL Server:

In addition to having an SQL Server 2016 instance with R Server installed, the following components are needed on a client machine

The Comprehensive R Archive Network

RStudio (optional)

Visual Studio 2015 R Tools

This list is a change from the previous list I have provided as RTVS contains an installation of R Client, there is no need to download that as well. You do not need to download Microsoft R Open if you are using R Server either.  Once RTVS is installed, there is a menu option on the R Tools window. Selecting Install R Client from the menu will handle the information. Unfortunately, there is no change to the menu option once R Client is installed, it always looks like you should install it.  To find out if R Client has been installed, look in the Workspaces window.

In other words, fewer dependencies and an easier installation process.  Read the whole thing to avoid RevoScaleR errors in your code post-upgrade.

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Generating R Services Stored Procedures From R

Published 2017-04-05 by Kevin Feasel

David Smith describes sqlrutils, an R function to generate SQL Server R Services stored procedures:

If you’ve created an R function (say, a routine to clean up missing values in a data set, or a function to make forecasts using a machine learning model), and you want to make it easy for DBAs to use it, it’s now possible to publish R functions as a SQL Server 2016 stored procedure. The sqlrutils package provides tools to convert an existing R function to a stored procedure which can then be executed by anyone with authenticated access to the database — even if they don’t know any R.

To use an R function as a stored procedure, you’ll need SQL Server 2016 with R Services installed. You’ll also need to use the sqlrutils package to publish the function as a stored procedure: it’s included with both Microsoft R Client (available free) and Microsoft R Server (included with SQL Server 2016), version 9.0 or later.

Compare this against R Tools for Visual Studio, with which you can generate stored procedures from the IDE.

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ggedit 0.2.0

Published 2017-04-04 by Kevin Feasel

Jonathan Sidi announces ggedit 0.2.0:

ggedit is an R package that is used to facilitate ggplot formatting. With ggedit, R users of all experience levels can easily move from creating ggplots to refining aesthetic details, all while maintaining portability for further reproducible research and collaboration.
ggedit is run from an R console or as a reactive object in any Shiny application. The user inputs a ggplot object or a list of objects. The application populates Bootstrap modals with all of the elements found in each layer, scale, and theme of the ggplot objects. The user can then edit these elements and interact with the plot as changes occur. During editing, a comparison of the script is logged, which can be directly copied and shared. The application output is a nested list containing the edited layers, scales, and themes in both object and script form, so you can apply the edited objects independent of the original plot using regular ggplot2 grammar.

This makes modifying ggplot2 visuals a lot easier for people who aren’t familiar with the concept of aesthetics and layers—like, say, the marketing team or management.

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Scalable Data Analytics

Published 2017-04-03 by Kevin Feasel

David Smith covers a recent Microsoft Data Science team talk at Strata:

The tutorial covers many different techniques for training predictive models at scale, and deploying the trained models as predictive engines within production environments. Among the technologies you’ll use are Microsoft R Server running on Spark, the SparkR package, the sparklyr package and H20 (via the rsparkling package). It also touches on some non-Spark methods, like the bigmemory and ff packages for R (and various other packages that make use of them), and using the foreach package for coarse-grained parallel computations. You’ll also learn how to create prediction engines from these trained models using the mrsdeploy package.

Check out the post as well as the tutorial David links.

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doAzureParallel

Published 2017-03-31 by Kevin Feasel

JS Tan announces a new R package:

For users of the R language, scaling up their work to take advantage of cloud-based computing has generally been a complex undertaking. We are therefore excited to announce doAzureParallel, a lightweight R package built on Azure Batch that allows you to easily use Azure’s flexible compute resources right from your R session. The doAzureParallel package complements Microsoft R Server and provides the infrastructure you need to run massively parallel simulations on Azure directly from R.

The doAzureParallel package is a parallel backend for the popular foreach package, making it possible to execute multiple processes across a cluster of Azure virtual machines with just a few lines of R code. The package helps you create and manage the cluster in Azure, and register it as a parallel backend to be used with foreach.

It’s an interesting alternative to building beefy R servers.

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