Overview of statistical learning theory

Teaching computer to read with linear regression

In the first part of the file tutorial2.py of repository Tensorflow in my github, you have the commented version of the MINST tutorial for experts in Tensorflow. Tensorflow is an opensource API for several languages that act as frontend for a machine learning backend that is quite flexible. What I was surprised for is the result of this first small exercise, that is: you take the pixel of the MINST package for character recognition traning.

Dynamic mapping with Shapefiles and python

In a two days coding challenge over workers day holiday, I decided to play with maps as means to plot information. What I decided to are use are the widely available shapefiles and python matplotlib packages, using mainly pandas and numpy to analyse data. You can find everything in this git repository. First of all you can start familiarising with shapefiles by plotting the pure patches, as in function mP in mapPlot.

Generational clash

The new prodigy behind Google translate

I read a lot of misconceptions this morning related to this article regarding Google Translate. Is not properly fresh news but this morning in my telegram group @scienza, this other popularization article has been posted that completely misunderstood the premises of the original academic article (also the so-called informed comments are not really , so I decided to try to keep the record straight and offer a question. In the article the approach is referred as a multitasking learning framework

CP Symmetry violation

Matter-Antimatter symmetry violation might have found it’s first culprit and have been recently published on Nature (here’s the arXiv https://arxiv.org/abs/1609.05216 ) Together with the results of AMS (pasted) have been an interesting 2016 for big collaborations. What can nuclear physics contribute to such big and fancy experiments and new quests for dark matter or CP symmetry? All these experiments use nuclei at one point or another of their experimental chain, all of them use the strong force and its low-energy extrapolation…

The magical mystery world of nuclear reactions exposed.

Nuclear wave function in function of for the proton state, obtained by diagonalizing the self energy in the exact continuum used above. The first eigenvalue at -23.97 MeV (solid red line) is compared by the corresponding harmonic oscillator state multiplied by the square root of the spectroscopic factor (dashed red line), the second eigenvalue at -2.85 MeV (solid blue line) is similarly compared with harmonic oscillator state (dashed blue line).

Github returns

I am setting up and using the public github repository after many years. I decided to start releasing some old projects publicly, since seems apparent I will never have time to write anymore papers, nor to polish the code. Eventually, at least for these little “didactic” subprojects, I will start to do little explanatory videos, or blogposts, instead of articles just to save times and make the process more fluid.

Macbook Pro 2016

Macbook Pro 2016 update sports still LPDDR3 RAM memory, in 8GB or 16GB size, and 1866 or 2133 MHz CL11 or CL12. Frankly I’m furious that a 2300£ (starting from) laptop still uses a 9 years old standard, while a newer one is available since more than a year. Already the Skylake processor is a setback, but the DDR3 memory on a Intel graphics laptop is practically a scam. Dell XPS15 offers better specs since June, in roughly the same size.

Shakespearean Conondrum

Little feature in Times Higher Education and elsewhere

C# Lists and Dictionary

In C# there are several key differences to C++. Microsoft Website spells them all: https://msdn.microsoft.com/en-us/magazine/cc301520.aspx Garbage collector instead of deconstructors providing a different approach to micromenagment of memory and lists, jagged arrays and dynamic memory allocation are already available into the language. It supports also negative index to counting from the last element, similarly to Python. About lists instead of the usual self-made textbook-example class, there are specific embedded classes for Lists and Dictionaries.

Calculation of Skyrme Landau Parameters

Fun with conditional probability

Bayesian concept of probability is linked not with frequency, but with state of information. The processing of this information proceeds in a propositional sense. In fact there are semantic work related to the use of Bayesian statistic as foundation for programming languages (BLOG), First kind logic (MEBN , also look at the fun Of Starships and Klingon) and thus the foundation principles of Network-Centric warfare and commerce.

Property of Baysian calculation of proabability are sometimes difficult to grasp and very counter intuitive, interesting consideration can hide behind apparently trivial formulas that can help to answer questions like: If you know your neighbour has a son born on Tuesday, which is the probability your neighbour has two sons?

The Practice of Programming

I started reading “The Practice of Programming” by Kernigan and Pike.

The book hinges on the concepts of simplicity, clarity and generality as foundation of a good code. Eventually automation can bring something to the table generating code from algorithms.

It starts by the usual “obvious” remarks about style:

Value at Risk on expected return

Value at Risk on expected return is the lower bound for the loss in an investement respect to a probability. Is a way to estimating losses probabilities in terms of value, instead of standard deviation. E.g. in the case of , means that the investor have a probability of loosing € or more, investing € on the portfolio . Considering the system ergodic and thus all the variances of the titles summing up coherently to for a variance of the portfolio distributed within the normal distribution, this is simply calculated considering the quantile (the value of the distribution corresponding to a certain fraction of probability) .

No-Arbitrage condition

No Arbitrage states the inadmissibility of Free Lunch in applying a structure (metric?) to the prices. Considering a title with price and cash flow , or every time , where it is the discretized time . Then we have the two No-Arbitrage condition: Weak No-Arbitrage : if Strong No-Arbitrage: if and Let’s suppose a world where I can borrow money with fixed interest rate , which will be the price of a product with interest over one year?

Optimizing: the Minimum Variance (or Maximum Return) Portfolio example

The aim is the optimization either by maximizing total return (or minimizing risk), in keeping with the constraints of normalization for a given risk (or return). Thus Lagrange method is perfectly suited for the job. For minimizing risk, respect to a desired total return , one must consider the function of total risk and minimize the lagrangian with constrain over the desired return and sum to one of weights.

Investment Portfolio Basics

Theorical ArXiv of Cook and Rossi

There are several aspects of the paper of Norman Cook and Andrea Rossi that scream “amateurish”: from layout to typos (hoping they’re so), from historical concepts to bibliography, I’m not certainly the only one to have noted them.

But is the scientific thesis to be flawed, even without considering the disputed history of E-cat and LENR and possible prejudices one can have on the author and its reasons.

Calculation for Gaussian Matrix Elements

Example of Calculation

Beta decay logft

The comparative half life ft is useful to compare the strength of the and electron-capture processes over different nuclei. -decay half lives can span several orders of magnitude, from fraction of seconds to thousands of time the age of the universe. Some of these striking differences are due to relatively trivial energetic conditions, but the more interesting from a nuclear structure point of view are due to the wavefunction superposition and the angular momentum coupling.

The mistery of Nature’s sons

The website craft 101

When I kicked on WILT I learned some deal regarding the craft of the website productions. First of all I struggled with the DNS. I first of all found that exist two type of DNS configurations A and CNAME. A links to an IP-address, in other words the server IP. CNAME links to another http address, connecting via DNS for example http://phme.it to http://w__ww.phme.it. Then I decided to set up the WordPress network in subdirectory instead of subdomain, and I struggled with the infamous .