Quantum Bayesian Networks

April 30, 2017

I don’t use plates to eat Bayesian networks

Filed under: Uncategorized — rrtucci @ 2:02 am

I am referring here to the “plates” used by some to draw Bayesian networks. Here is why I don’t like them. Consider this diagram given as an example by the Wikipedia article on plate notation. In this diagram, I would replace
\theta by \theta^{M}, z by z^{NM}, and w by w^{NM}. F*** (forget) the plates.

This aversion of mine to plates is related to the following idiosyncratic notation of mine.

In computer code, I like to use x\_ for a random variable x and vx for a vector of N observations x. (In a latex document I might use \underline{x} for a random variable and \underline{x}^N for the N observations.)

A vector of x measurements vx is like a primitive version of the random variable x\_. In fact, from vx one can get an empirical distribution P_{emp}(x) which approximates the true distribution P(x) which defines the random variable x\_. That’s why when I see a statement like x\_ \sim P(x), I think of this as an ordinary equivalence relation. In fact,

x\_ \sim vx \sim P_{emp}(x) \sim  P(x)

are all equivalent in the limit of a large number of observations.

April 29, 2017

Miss Quantum Computing, may I introduce to you Miss Bayesian Hierarchical Models and Miss MCMC?

Filed under: Uncategorized — rrtucci @ 5:49 pm

Warning: Intense talk about computer software ahead. If you are a theoretical computer scientist, you better stop reading this now. Your weak constitution probably can’t take it.

When you enter the nerd paradise and secret garden that is Bayesforge.com (a free service on the Amazon cloud), you will see one folder named “Classical” and another named “Quantum”. Here is a screenshot of this taken from Henning Dekant’s excellent post in Linkedin

The “Quantum” folder contains some major open source quantum computing programs: Quantum Fog, Qubiter, IBM-QisKit (aka kiss-kit), QuTip, DWave, ProjectQ, Rigetti

The “Classical” folder contains some major Bayesian analysis open source programs: Marco Scutari’s bnlearn (R), Kevin Murphy’s BNT (Octave/matlab), OpenPNL (C++/matlab), PyMC, PyStan.

The idea is to promote cross fertilization between “Quantum” and “Classical” Bayesian statisticians.

Today I want to talk mostly about PyMC and PyStan. PyMC and PyStan deal with “Hierarchical Models” (Hmods). The other programs in the “Classical” folder deal with “Bayesian Networks”(Bnets).

Bnets and Hmods are almost the same thing. The community of people working on Bnets has Judea Pearl as one of its distinguished leaders. The community of people working on Hmods has Andrew Gelman as one of its distinguished leaders. You might know Gelman (Prof. at Columbia U.) from his great blog “Statistical Modeling, Causal Inference, and Social Science” or from one of his many books

Both PyStan and PyMC do MCMC (Markov Chain Monte Carlo) for Hmods. They are sort of competitors but also complementary.

PyStan (its GitHub repo here) is a Python wrapper of a computer program written in C++ called Stan. According to Wikipedia, “Stan is named in honour of Stanislaw Ulam, pioneer of the Monte Carlo method.” Prof. Gelman is one of the fathers of Stan (I mean the program, of course).

PyMC comes in 2 incompatible versions: 2.X and 3.X. Version 3 is more advanced and intends to replace Ver 2. PyMC2’s best sampler is a Metropolis-Hastings (MH) sampler. PyMC3 contains an MH sampler, but it also contains the “No U turns” or “NUTS” sampler that is supposed to be much faster than MH for large networks. Currently, Bayesforge contains only PyMC2, but the next version will contain both PyMC2 and PyMC3. As an added bonus, PyMC3 comes with Theano, one of the leading deep neural networks frameworks.

Check out this really cool course:

Sta-663 “Statistical Programming” , available at GitHub, taught at Duke U. by Prof. Chi Wei Cliburn Chan.

This wonderful course has some nice jupyter notebooks illustrating the use of PyMC2, PyMC3 and PyStan. Plus it contains discussions of many other statistical programmimg topics. I love it. It has a similar philosophy to BayesForge, namely to do statistical programming with jupyter notebooks because they are great for communicating your ideas to others and allow you to combine seamlessly various languages like Python, R, Octave, etc

April 21, 2017

Real Artistes Ship!

Filed under: Uncategorized — rrtucci @ 7:33 pm

Today we finally unveiled to the public our http://www.BayesForge.com home page which contains instructions on how to sign up to our free service on the Amazon cloud. In the immortal words of Steve Jobs, “Real Artists Ship”. We ain’t called artiste-qb.net for nothing πŸ™‚

The exploding-reassembling Vitruvian-Metropolis Firefly Robot

April 8, 2017

Welcome to BayesForge, a free service on the Amazon cloud

Filed under: Uncategorized — rrtucci @ 7:08 am

Our company artiste-qb.net is proud to announce BayesForge (BF), our new service on AWS (Amazon Web Services). BayesForge is not yet open for business but will open in a week or less. The purpose of this blog post is to give an overview and teaser of what is coming.

Henning Dekant will give a tour of BF to those who attend the meeting on April 21 of the Toronto Quantum Computing Meetup.

Why AWS?

The Amazon cloud is one of the largest and Amazon offers an incredible deal to all its customers. Anybody with a credit card can get an AWS Free Tier account. An AWS Free Tier account gives you one full year of free cloud use (there are some upper bounds on usage but very generous ones). Furthermore, you can open a separate AWS Free Tier account in the name of your spouse and each of your children. Amazon doesn’t seem to care!! Only Jeff Bezos could be so crazy generous. Once you have an AWS Free Tier account, you can use it to play with BayesForge for a whole year, free of charge. You don’t have to be a student to do this.

What can you do with BayesForge?

BF allows you to write Jupyter notebooks on your web browser in a wide variety of languages and run/store those notebooks on the cloud. (Besides the web browser, no additional software needs to be installed on your computer). We have installed Jupyter kernels for Python-3, Python-2, R, Octave (clone of matlab) and bash. This means you can write/run a notebook in which you use one of those languages exclusively. We have also installed Rmagic and Octavemagic which allows you to write a notebook in Python but dip temporarily into R or Octave.

What software packages does BayesForge include?

BF comes with 2 folders called “Classical” and “Quantum”. The “Quantum” folder contains a large selection of open source quantum computing software, including our own Quantum Fog and Qubiter, and also open source qc software from DWave, IBM, Rigetti, etc. The “Classical” folder contains a large selection of open source software for doing classical bayesian statistical analysis.

This is the logo of BayesForge (graphics by our inhouse artiste and Gimp wizard, Henning Dekant. BayesForge name suggested by Gavin Dekant)

“True gold is not afraid of fire.”
(Chinese Proverb)

“Incus robust malleum non timet”
“A strong anvil need not fear the hammer.”
(Latin Proverb)

April 6, 2017

Reaching Quantum Escape Velocity

Filed under: Uncategorized — rrtucci @ 5:42 pm

The term “Reaching Quantum Supremarcy”, coined by John Preskill, is usually used to refer to the first time a quantum computer can perform in minutes a calculation that would take the best classical computers centuries to perform. I prefer to call that “Reaching Quantum Escape Velocity”.

I love the term “Quantum Supremacy” too, but I like to use it differently, as in “Google, IBM and Microsoft are vying for Quantum Supremacy”, viz., to dominate the qc market. This second meaning is the one being used in my upcoming movie entitled “Quantum Supremacy”.

I prepared the following poster to promote the concept of reaching quantum escape velocity. It recycles some art from a previous blog post of mine.

April 5, 2017

Tao Yin teleports (the old fashioned way) 2 entangled cats from Germany to China

Filed under: Uncategorized — rrtucci @ 5:11 pm

In this photo you can see Tao Yin at the Frankfurt airport, before boarding an airplane to China, transporting cat #1. Cat #2 was teleported by his wife on same flight. One small pet per passenger allowed. Cats 1 and 2 are friends that were entangled at a distance during the flight.

Dr. Tao Yin obtained a Ph.D. in Physics at the end of last year from
The Goethe University in Frankfurt. He started at artiste-qb.net as a long-distance intern last summer, but he is now CTO and part owner of artiste-qb.net . He has quickly become an important part of our company. He has just moved from Frankfurt-Germany to Shenzhen-China, where he will continue to represent us. Shenzhen, population ~ 11 million, is one of the 5 largest cities in China, a technology power house located immediately north of Hong Kong.

Tao brings to artiste-qb.net excellent computer skills and knowledge of physics. We are also relying on him to translate to Mandarin Chinese some of our software docs. For example, he translated the Jupyter notebooks quantum_compiler_intro.ipynb to quantum_compiler_intro_CN.ipynb. These jupyter notebooks explain how to use the quantum compiler in our open source software Qubiter. Qubiter has had a fully-functional quantum compiler since the first week of Jan of 2017. Currently, Qubiter is the only software to offer a quantum compiler of this kind.

April 1, 2017

April the Giraffe has Baby

Filed under: Uncategorized — rrtucci @ 6:32 pm

Today, April the Giraffe had a baby boy calf after 15 months of taxing pregnancy, the progress of which has been anxiously followed via webcam by millions of animal lovers throughout the world. April lives at the Animal Adventure Park near Binghamton, NY, although conservative rumor mills claim that her real birth certificate is from Kenya.

To congratulate April and hubby Oliver on the new addition to their family, we have sent them a baby bib (size=”giraffe”), a baby bottle and a copy of our latest book “Quantum Computer Programming for Giraffes” printed on paper made from tasty Acacia tree leaves that were made-in-America.

We here at artiste-qb.net are passionate animal lovers and have a long tradition of sending gifts to giraffes and other mammals, including the least noble ones. For example, on a previous occasion, we sent to Jack Ma (founder of Alibaba) one of our stylish baseball caps, and to the new baby of Mark Zuckerberg a copy of our book “How to program the Facebook quantum computer with QuPy”. (You too can have a copy of these items for a very reasonable price. They are especially popular with people who want to make an impression at Silicon Valley cocktail parties).

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