How to design a model visualisation @ Gdansk satRdays


I had amazing weekend in Gdansk thanks to the satRday conference organized by Olgun Aydin, Ania Rybinska and Michal Maj.

Together with Hanna Piotrowska we had a talk ,,Machine learning meets design. Design meets machine learning”. Hanna redesigned DALEX visualisations (DALEX is a set of tools for visual explanation of predictive ML models). During the talk she explained what and why was changed.

See for example the metamorphosis of the Break Down explainer. How many differences can you spot?

Every change (axis, reading order, spacing, colors, descriptions, background, annotations) serves some purpose.

Find our presentation at slideshare.

List of satRday talks (machine learning was quite popular).

Hanna design is implemented in ggplot2 thanks to Tomasz Mikołajczyk and in D3 thanks to Huber Baniecki! Find more examples of how to use new plots here.

Make it explainable!

Most people make the mistake of thinking design is what it looks like… People think it’s this veneer — that the designers are handed this box and told, ‚Make it look good!’ That’s not what we think design is. It’s not just what it looks like and feels like. Design is how it works.

Steve Jobs, The New York Times, 2003.

Same goes with interpretable machine learning.
Recently, I am talking a lot about interpretations and explainability. And sometimes I got impression that techniques like SHAP, Break Down, LIME, SAFE are treated like magical incantations that converts complex predictive models into ,,something interpretable’’.

But interpretability/explainability is not a binary feature that you have it or not. It’s a process. The goal is to increase our understanding of the model behavior. Try different techniques to broaden the knowledge about the model or about model predictions.
Maybe you will never explain 100%, but you will understand more.

XAI/IML (eXplainable Artificial Intelligence/Interpretable Machine Learning) techniques can be used not only for post-hoc explainability, but also for model maintenance, debugging or in early phases of crisp modeling. Visual tools like PDP/ALE/CeterisParibus will change the way how we approach modeling and how we interact with models. We as model developers, model auditors or users.

Together with Tomasz Burzykowski from UHasselt we work on a book about the methodology for visual exploration, explanation and debugging predictive models.

Find the early version here https://pbiecek.github.io/PM_VEE/.

There is a lot of R snippets that shows how to use DALEX (and sometimes other packages like shapper, ingredients, iml, iBreakDown, condvis, localModel, pdp) to better understand some aspects of your predictive model.

It’s a work in process and even in an early dirty phase (despite the fact that we have started a year ago).
Feel free to comment it, or suggest improvements. Easiest way to do this is to add a new issue.

Code snippets are fully thanks to archivist hooks. I think that it’s a first book that uses archivist hooks for blended experience. You can read about a model online and in just one line of code you can download an object to your R console.

First chapters show how to use Ceteris Paribus Profiles / Individual Conditional Expectations to perform what-if/sensitivity analysis of a model.

DALEX for keras and parsnip

DALEX is a set of tools for explanation, exploration and debugging of predictive models. The nice thing about it is that it can be easily connected to different model factories.

Recently Michal Maj wrote a nice vignette how to use DALEX with models created in keras (an open-source neural-network library in python with an R interface created by RStudio). Find the vignette here.
Michal compared a keras model against deeplearning from h2o package, so you can check which model won on the Titanic dataset.

Next nice vignette was created by Szymon Maksymiuk. In this vignette Szymon shows how to use DALEX with parsnip models (parsnip is a part of the tidymodels ecosystem, created by Max Kuhn and Davis Vaughan). Models like boost_tree, mlp and svm_rbf are competing on the Titanic data.

These two new vignettes add to our collection how to use DALEX with mlr, caret, h2o and others model factories.

Explore the landscape of R packages for automated data exploration

Do you spend a lot of time on data exploration? If yes, then you will like today’s post about AutoEDA written by Mateusz Staniak.

If you ever dreamt of automating the first, laborious part of data analysis when you get to know the variables, print descriptive statistics, draw a lot of histograms and scatter plots – you weren’t the only one. Turns out that a lot of R developers and users thought of the same thing. There are over a dozen R packages for automated Exploratory Data Analysis and the interest in them is growing quickly. Let’s just look at this plot of number of downloads from the official CRAN repository.

Replicate this plot with

New tools arrive each year with a variety of functionalities: creating summary tables, initial visualization of a dataset, finding invalid values, univariate exploration (descriptive and visual) and searching for bivariate relationships.

We compiled a list of R packages dedicated to automated EDA, where we describe twelve packages: their capabilities, their strong aspects and possible extensions. You can read our review paper on arxiv: https://arxiv.org/abs/1904.02101.

Spoiler alert: currently, automated means simply fast. The packages that we describe can perform typical data analysis tasks, like drawing bar plot for each categorical feature, creating a table of summary statistics, plotting correlations, with a single command. While this speeds up the work significantly, it can be problematic for high-dimensional data and it does not take the advantage of AI tools for actual automatization. There is a lot of potential for intelligent data exploration (or model exploration) tools.

More extensive list of software (including Python libraries and web applications) and papers is available on Mateusz’s GitHub. Researches can follow our autoEDA project on ResearchGate.

iBreakDown: faster, prettier and more precise explanations for predictive models (with interactions)

LIME and SHAP are two very popular methods for instance level explanations of machine learning models (XAI).
They work nicely for images and text inputs, but share similar weakness in case of tabular data: explanations are additive while complex models are (sometimes) not. iBreakDown addresses this problem.

iBreakDown is a a successor of the breakDown package. Yesterday it has arrived on CRAN. Key new features are:

– It identifies and shows feature interactions (if there are local interactions in the model).
– It is much faster. For additive explanations the complexity is O(p) instead of O(p^2).
– The plotD3 function creates an interactive D3-based break-down plot (thanks to r2d3).
– iBreakDown has a new design, created by Hanna Dyrcz. We will have a talk about it ,,Machine learning meets design. Design meets machine learning.” at satRdays. Try the new theme theme_drwhy()!.
– It shows explanation level uncertainty – how good are explanations?

A methodology behind this package is described in the iBreakDown: Uncertainty of Model Explanations for Non-additive Predictive Models.

A nice titanic-powered use-case is described in the titanic vignette.

An example of the D3 interactive explainer is here.

Some intuition is introduced in the Visual Exploration, Explanation and Debugging (working version, still in progress).

iBreakDown is a part of the DrWhy.AI family of explainers consistent with the DALEX.

Let us know if you like it. Feel free to create a pull request with new features, add issue with new idea or star the github repository if you like this package.

DALEX has a new skin! Learn how it was designed at gdansk2019.satRdays

DALEX is an R package for visual explanation, exploration, diagnostic and debugging of predictive ML models (aka XAI – eXplainable Artificial Intelligence). It has a bunch of visual explainers for different aspects of predictive models. Some of them are useful during model development some for fine tuning, model diagnostic or model explanations.

Recently Hanna Dyrcz designed a new beautiful theme for these explainers. It’s implemented in the DALEX::theme_drwhy() function.
Find some teaser plots below. A nice Interpretable Machine Learning story for the Titanic data is presented here.

Hanna is a very talented designer. So I’m super happy that at the next satRdays @ gdansk2019 we will have a joint talk ,,Machine Learning meets Design. Design meets Machine Learning”.

New plots are available in the GitHub version of DALEX 0.2.8 (please star if you like it/use it. This helps to attract new developers). Will get to the CRAN soon (I hope).

Instance level explainers, like Break Down or SHAP

Instance level profiles, like Ceteris Paribus or Partial Dependency

Global explainers, like Variable Importance Plots

See you at satRdays!

shapper is on CRAN, it’s an R wrapper over SHAP explainer for black-box models

Written by: Alicja Gosiewska

In applied machine learning, there are opinions that we need to choose between interpretability and accuracy. However in field of the Interpretable Machine Learning, there are more and more new ideas for explaining black-box models. One of the best known method for local explanations is SHapley Additive exPlanations (SHAP).

The SHAP method is used to calculate influences of variables on the particular observation. This method is based on Shapley values, a technique borrowed from the game theory. SHAP was introduced by Scott M. Lundberg and Su-In Lee in A Unified Approach to Interpreting Model Predictions NIPS paper. Originally it was implemented in the Python library shap.

The R package shapper is a port of the Python library shap. In this post we show the functionalities of shapper. The examples are provided on titanic_train data set for classification.

While shapper is a port for Python library shap, there are also pure R implementations of the SHAP method, e.g. iml or shapleyR.

Installation

The shapper wraps up the Python library, therefore installation requires a bit more effort than installation of an ordinary R package.

Install the R package shapper

First of all we need to install shapper, this may be the stable release from CRAN

or the developer version form GitHub.

Install the Python library shap

Before you run shapper, make sure that you have installed Python.

Python library shap is required to use shapper. The shap can be installed both by Python or R. To install it through R, you an use function install_shap() from the shapper package.

If you experience any problems related to the installation of Python libraries or evaluation of Python code, see the reticulate documentation. The shapper access Python within reticulate, therefore the solution to the problem is likely to be in there ;-).

Would you survive sinking of the RMS Titanic?

The example usage is presented on the titanic_train dataset from the R package titanic. We will predict the Survived status. The other variables used by the model are: Pclass, Sex, Age, SibSp, Parch, Fare and Embarked.

Let’s build a model

Let’s see what are our chances assessed by the random forest model.

Prediction to be explained

Let’s assume that we want to explain the prediction of a particular observation (male, 8 years old, traveling 1-st class embarked at C, without parents and siblings.

Model prediction for this observation is .558 for survival.

Here shapper starts

To use the function shap() function (alias for individual_variable_effect()) we need four elements

  • a model,
  • a data set,
  • a function that calculated scores (predict function),
  • an instance (or instances) to be explained.

The shap() function can be used directly with these four arguments, but for the simplicity here we are using the DALEX package with preimplemented predict functions.

The explainer is an object that wraps up a model and meta-data. Meta data consists of, at least, the data set used to fit model and observations to explain.

And now it’s enough to generate SHAP attributions with explainer for RF model.

Plotting results

To generate a plot of Shapley values you can simply pass an object of class importance_variable_effect to a plot() function. Since we are interested in the class Survived = 1 we may add additional parameter that filter only selected classes.

Labels on y-axis show values of variables for this particular observation. Black arrows show predictions of model, in this case, probabilities of each status. Other arrows show effect of each variable on this prediction. Effects may be positive or negative and they sum up to the value of prediction.

On this plot we can see that model predicts that the passenger will survive. Changes are higher due to young age and 1st class, only the Sex = male decreases chances of survival for this observation.

More models

It is useful to contrast prediction of two models. Here we will show how to use shapper for such contrastive explanations.

We will compare randomForest with svm implemented in the e1071.

This model predict 32.5% chances of survival.

Shapley values plot may be modified. To show more than one model you can pass more individual_variable_plot objects.

To see only attributions use option show_predcited = FALSE.

More

Documentation and more examples are available at https://modeloriented.github.io/shapper/. The stable version of the package is on CRAN, the development version is on GitHub (https://github.com/ModelOriented/shapper). Shapper is a part of the DALEX universe.

x-mas tRees with gganimate, ggplot, plotly and friends

At the last homework before Christmas I asked my students from DataVisTechniques to create a ,,Christmas style” data visualization in R or Python (based on simulated data).

Libaries like rbokeh, ggiraph, vegalite, shiny+ggplot2 or plotly were popular last year. This year there are also some nice submissions that use gganimate.

Find source codes here. Plots created last year are here.
And here are homeworks from this year.

Trees created with gganimate (and gifski)



Trees created with ggplot2 (and sometimes shiny)









Trees created with plotly


Trees created with python


Trees created with rbokeh


Trees created with vegalite


Trees created with ggiraph

Data, movies and ggplot2

Yet another boring barplot?
No!
I’ve asked my students from MiNI WUT to visualize some data about their favorite movies or series.
Results are pretty awesome.
Believe me or not, but charts in these posters are created with ggplot2 (most of them)!

Star Wars

Fan of StaR WaRs? Find out which color is the most popular for lightsabers!
Yes, these lightsabers are created with ggplot2.
Would you guess which characters are overweighed?
Find the R code and the data on the GitHub.

Harry Pixel

Take fames from Harry Potter movies, use k-means to extract dominant colors for each frame, calculate derivative for color changes and here you are.
The R code and the poster are here.
(steep derivatives in color space is a nice proxy for dynamic scenes).

Social Network for Super Heroes

Have you ever wondered how the distribution of super powers looks like among Avengers?
Check put this poster or dive in the data.

Pardon my French, but…

Scrap transcripts from over 100k movies, find out how many curse words you may find in these movies, plot these statistics.
Here are sources and the poster.
(Bonus Question 1: how curse words are related to Obama/Trump presidency?
Bonus Question 2: is the number of hard curse words increasing or not?)

Rick and Morty

Interested in the demography of characters from Rick and Morty?
Here is the R code and the poster.
(Tricky question: what is happening with season 3?)

Twin Peaks

Transcripts from Twin Peaks are full of references to coffee and donuts.
Except the episode in which the Laura’s murdered is revealed (ups, spoiler alert).
Check out this by yourself with these scripts.

The Lion King

Which Disney’s movie is the most popular?
It wasn’t hard to guess.

Box Office

5D scatterplots?
Here you have.

Next time I will ask my students to visualize data about R packages…
Or maybe you have some other ideas?

Ceteris Paribus Plots – a new DALEX companion

If you like magical incantations in Data Science, please welcome the Ceteris Paribus Plots. Otherwise feel free to call them What-If Plots.

Ceteris Paribus (latin for all else unchanged) Plots explain complex Machine Learning models around a single observation. They supplement tools like breakDown, Shapley values, LIME or LIVE. In addition to feature importance/feature attribution, now we can see how the model response changes along a specific variable, keeping all other variables unchanged.

How cancer-risk-scores change with age? How credit-scores change with salary? How insurance-costs change with age?

Well, use the ceterisParibus package to generate plots like the one below.
Here we have an explanation for a random forest model that predicts apartments prices. Presented profiles are prepared for a single observation marked with dashed lines (130m2 apartment on 3rd floor). From these profiles one can read how the model response is linked with particular variables.

Instead of original values on the OX scale one can plot qunatiles. This way one can put all variables in a single plot.

And once all variables are in the same scale, one can compare two or more models.

Yes, they are model agnostic and will work for any model!
Yes, they can be interactive (see plot_interactive function or examples below)!
And yes, you can use them with other DALEX explainers!
More examples with R code.