Overviews of Graph Classification and Network Clustering methods

Thanks to Sebastian Raschka I am able to share this great GitHub overview page of relevant graph classification techniques, and the scientific papers behind them. The overview divides the algorithms into four groups:

  1. Factorization
  2. Spectral and Statistical Fingerprints
  3. Deep Learning
  4. Graph Kernels

Moreover, the overview contains links to similar collections on community detectionclassification/regression trees and gradient boosting papers with implementations.

As well as a link to relevant graph classification benchmark datasets.

ArchiGAN: Designing buildings with reinforcement learning

ArchiGAN: Designing buildings with reinforcement learning

I’ve seen some uses of reinforcement learning and generative algorithms for architectural purposes already, like these evolving blueprints for school floorplans. However, this new application called ArchiGAN blew me away!

ArchiGAN (try here) was made by Stanislas Chaillou as a Harvard master’s thesis project. The program functions in three steps:

  1. building footprint massing
  2. program repartition
  3. furniture layout
Generation stack image
Stanislas’ three generation steps

Each of these three steps uses a TensorFlow Pix2Pix GAN-model (Christopher Hesse’s implementation) in the back-end, and their combination makes for a entire apartment building “generation stack” — according to Stanislas — which also allows for user input at each step.

The design of a building can be inferred from the piece of land it stands on. Hence, Stanislas fed his first model using GIS-data (Geographic Information System) from the city of Boston in order to generate typical footprints based on parcel shapes. 

Model 1 results image
The inputs and outputs of model I

Stanislas’ second model was responsible for repartition and fenestration (the placement of windows and doors). This GAN took the footprint of the building (the output of model I) as input, along with the position of the entrance door (green square), and the positions of the user-specified windows.

Stanislas used a database of 800+ plans of apartments for training. To visualize the output, rooms are color-coded and walls and fenestration are blackened.

Model II results image
The inputs and outputs of model II

Finally, in the third model, the rooms are filled with appropriate furniture. What training data Stanislas has used here, he did not specify in the original blog.

Model III results image
The inputs and outputs of model III

Now, to put all things together, Stanislas created a great interactive tool you can play with yourself. The original NVIDEA blog contains some great GIFs of the tool being used:

1HL5IIWCrgTnaRX3I63rFpQ

Stanislas’ GAN-models progressively learned to design rooms and realistically position doors and windows. It took about 250 iterations to get some realistic floorplans out of the algorithm. Here’s how an example learning sequence looked like:

Architectural sequence image
Visualization of the training process

Now, Stanislas was not done yet. He also scaled the utilization of GANs to design whole apartment buildings. Here, he chains the models and processes multiple units as single images at each step.

Apartment building generation pipeline image
Generating whole appartment blocks using ArchiGAN

Stanislas did other cool things to improve the flexibility of his ArchiGAN models, about which you can read more in the original blog. Let these visuals entice you to read more:

GAN-enabled building layouts image
ArchiGAN scaled to handle whole appartment blocks and neighborhoods.

I believe a statistical approach to design conception will shape AI’s potential for Architecture. This approach is less deterministic and more holistic in character. Rather than using machines to optimize a set of variables, relying on them to extract significant qualities and mimicking them all along the design process represents a paradigm shift.

Stanislas Chaillou (via)

I am so psyched about these innovative applications of machine learning, so please help me give Stanislas the attention and credit he deserved.

Currently, Stanislas is Data Scientist & Architect at Spacemaker.ai. Read more about him in his NVIDEA developer bio here. He recently published a sequence of articles, laying down the premise of AI’s intersection with Architecture. Read here about the historical background behind this significant evolution, to be followed by AI’s potential for floor plan design, and for architectural style analysis & generation.

Overview of built-in colors in R

Overview of built-in colors in R

Most of my data visualizations I create using R programming — as you might have noticed from the content of my website.

Though I am colorblind myself, I love to work with colors and color palettes in my visualizations. And I’ve come across quite some neat tricks in my time.

For instance, did you it’s super easy to create a reproducible though custom color palette? Or that there’s a quick reference card for ggplot2’s built-in colors? Or, and this is this blog post’s main subject, that you can access all built-in base colors using colors()!

This last trick, I learned in this recent blog post I came across, by Chisato. She explored all colors() base R incorporates, using the new ggforce and ggraph packages (thank you Thomas Lin Petersen!). Her exploration resulted in some nice visual overviews, which you can view in more detail in the original blog here.

Colors() with no color family
Colors() that have at least 5 colors in their family
Colors() with similar names
Simulate Datasets with DrawData.xyz

Simulate Datasets with DrawData.xyz

Vincent Warmerdam shared his new tool to quickly simulate artificial datasets: www.drawdata.xyz.

The drawdata.xyz tool allows you to easily create your own line- and scatter-plot with different groups of datapoints following specific x-y patterns.

After drawing your data, you can just click to export your new dataset to csv or json format.

xy
106.04204.11a
118.84205.16a
86.89213.17a
55.70223.59a
112.36212.67a
77.50178.74a
139.59215.85a
79.72176.98a
111.07165.06a

[
{“x”:106.03951109571048,”y”:295.89491361991946,”color”:”a”},{“x”:118.84116584600102,”y”:294.83836796770856,”color”:”a”},{“x”:86.89356822087684,”y”:286.82917421691593,”color”:”a”},{“x”:55.704734781797704,”y”:276.40994950952324,”color”:”a”},{“x”:112.35769167604312,”y”:287.3270528058234,”color”:”a”},{“x”:77.49742862117122,”y”:321.2601748923149,”color”:”a”},{“x”:139.58612733846104,”y”:284.1490846490819,”color”:”a”},{“x”:79.72318039443124,”y”:323.02279632733473,”color”:”a”},{“x”:111.07206207974374,”y”:334.9434522924817,”color”:”a”},
…]

Vincent was inspired by this d3.js tool by Eli.

Try his drawdata.xyz out yourself!

17 Principles of (Unix) Software Design

17 Principles of (Unix) Software Design

I came across this 1999-2003 e-book by Eric Raymond, on the Art of Unix Programming. It contains several relevant overviews of the basic principles behind the Unix philosophy, which are probably useful for anybody working in hardware, software, or other algoritmic design.

First up, is a great list of 17 design rules, explained in more detail in the original article:

  1. Rule of Modularity: Write simple parts connected by clean interfaces.
  2. Rule of Clarity: Clarity is better than cleverness.
  3. Rule of Composition: Design programs to be connected to other programs.
  4. Rule of Separation: Separate policy from mechanism; separate interfaces from engines.
  5. Rule of Simplicity: Design for simplicity; add complexity only where you must.
  6. Rule of Parsimony: Write a big program only when it is clear by demonstration that nothing else will do.
  7. Rule of Transparency: Design for visibility to make inspection and debugging easier.
  8. Rule of Robustness: Robustness is the child of transparency and simplicity.
  9. Rule of Representation: Fold knowledge into data so program logic can be stupid and robust.
  10. Rule of Least Surprise: In interface design, always do the least surprising thing.
  11. Rule of Silence: When a program has nothing surprising to say, it should say nothing.
  12. Rule of Repair: When you must fail, fail noisily and as soon as possible.
  13. Rule of Economy: Programmer time is expensive; conserve it in preference to machine time.
  14. Rule of Generation: Avoid hand-hacking; write programs to write programs when you can.
  15. Rule of Optimization: Prototype before polishing. Get it working before you optimize it.
  16. Rule of Diversity: Distrust all claims for “one true way”.
  17. Rule of Extensibility: Design for the future, because it will be here sooner than you think.

Moreover, the book contains a shortlist of some of the philosophical principles behind Unix (and software design in general): 

  • Everything that can be a source- and destination-independent filter should be one.
  • Data streams should if at all possible be textual (so they can be viewed and filtered with standard tools).
  • Database layouts and application protocols should if at all possible be textual (human-readable and human-editable).
  • Complex front ends (user interfaces) should be cleanly separated from complex back ends.
  • Whenever possible, prototype in an interpreted language before coding C.
  • Mixing languages is better than writing everything in one, if and only if using only that one is likely to overcomplicate the program.
  • Be generous in what you accept, rigorous in what you emit.
  • When filtering, never throw away information you don’t need to.
  • Small is beautiful. Write programs that do as little as is consistent with getting the job done.

If you want to read the real book, or if you just want to support the original author, you can buy the book here:

Let me know which of these and other rules and principles you apply in your daily programming/design job.

Dynamic Programming MIT Course

Dynamic Programming MIT Course

Cover image by xkcd

Over the last months I’ve been working my way through Project Euler in my spare time. I wanted to learn Python programming, and what better way than solving mini-problems and -projects?!

Well, Project Euler got a ton of these, listed in increasing order of difficulty. It starts out simple: to solve the first problem you need to write a program to identify multiples of 3 and 5. Next, in problem two, you are asked to sum the first thousand even Fibonacci numbers. Each problem, the task at hand gets slighly more difficult…

For me, Project Euler combines math, programming, and stats in a way that really keeps me motivated to continue and learn new concepts and programming / problem-solving approaches.

However, at problem 31, I really got stuck. For several hours, I struggled to solve it in a satisfactory fashion, even though most other problems only take 5-90 minutes.

After hours of struggling, I pretty much gave up, and googled some potential solutions. Aparently, the way to solve problem 31, is to take a so-called dynamic programming approach.

Dynamic programming is both a mathematical optimization method and a computer programming method. The method was developed by Richard Bellman in the 1950s and has found applications in numerous fields, from aerospace engineering to economics. In both contexts it refers to simplifying a complicated problem by breaking it down into simpler sub-problems in a recursive manner. While some decision problems cannot be taken apart this way, decisions that span several points in time do often break apart recursively. Likewise, in computer science, if a problem can be solved optimally by breaking it into sub-problems and then recursively finding the optimal solutions to the sub-problems, then it is said to have optimal substructure.

https://en.wikipedia.org/wiki/Dynamic_programming

Now, this sounded like something I’d like to learn more about! I was already quite familiar with recursive problems and solutions, but this dynamic programming sounded next-level.

So I googled and googled for tutorials and other resources, and I finally came across this free 2011 MIT course that I intend to view over the coming weeks.

There’s even a course website with additional materials and assignments (in Python).

ASSN #TOPICSPROBLEM SETSSOLUTIONS
1Asymptotic complexity, recurrence relations, peak findingProblem Set 1 (PDF)
Problem Set 1 Code (ZIP)
Problem Set 1 Solutions (PDF)
2Fractal rendering, digital circuit simulationProblem Set 2 (PDF)
Problem Set 2 Code (ZIP)
Problem Set 2 Solutions (PDF)
Problem Set 2 Code Solutions (ZIP – 7.7MB)
3Range queries, digital circuit layoutProblem Set 3 (PDF)
Problem Set 3 Code (ZIP – 3.2MB)
Problem Set 3 Solutions (PDF)
Problem Set 3 Code Solutions (ZIP – 15.7MB)
4Hash functions, Python dictionaries, matching DNA sequencesProblem Set 4 (PDF)
Problem Set 4 Code (GZ – 12.4MB) (kfasta.py courtesy of Kevin Kelley, and used with permission.)
Problem Set 4 Solutions (PDF)
Problem Set 4 Code Solutions (ZIP)
5The Knight’s Shield, RSA public key encryption, image decryptionProblem Set 5 (PDF)
Problem Set 5 Code (ZIP)
Problem Set 5 Grading Explanation (PDF)
Problem Set 5 Solutions (PDF)
Problem Set 5 Code Solutions (ZIP)
6Social networks, Rubik’s Cube, DijkstraProblem Set 6 (PDF)
Problem Set 6 Code (ZIP – 2.9MB) (nhpn.py courtesy of Punyashloka Biswal and Michael Lieberman; Pocket Cube Solver courtesy of Huan Liu and Anh Nguyen. Used with permission.)
Problem Set 6 Solutions (PDF)
Problem Set 6 Code Solutions (ZIP)
7Seam carving, stock purchasing and knapsackProblem Set 7 (PDF)
Seam Carving for Content-Aware Image ResizingProblem Set 7 Code (ZIP) (Sunset image © source unknown. All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/fairuse.)Problem Set 7 Answer Template (ZIP)Problem Set 7 Grading Explanation (PDF)
Problem Set 7 Solutions (PDF)
Problem Set 7 Code Solutions (ZIP)

Will you join me? And let me know what you think!

For those less interested in (dynamic) programming but mostly in machine learning, there’s this other great MIT OpenCourseWare youtube playlist of their Artificial Intelligence course. I absolutely loved that course and I really powered through it in a matter of weeks (which is why I am already psyched about this new one). I learned so much new concepts, and I strongly recommend it. Unfortunately, the professor recently passed away.