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SCHEMENAUER AND THE XOR GATE

2011-07-20T17:51:00.019+05:30

SCHEMENAUER AND THE XOR GATE

IMPLEMENTING ANN IN PYTHON

I was searching for Artificial Neural Networks (ANN) implementation in Python. I came across the following;

FANN - C library with python bindings
PyBrain
NeuroLab
PyNN
BPNN - Not a library, solitary script by Neil Schemenauer

THE XOR PROBLEM

The XOR problem has some history in the evolution of ANN methods. The XOR function is not linearly separable and cannot be realised using only one layer of ANN.

TINKERING WITH SCHEMENAUER'S CODE

Schemenauer's code has default training values for a 2 input XOR gate.

Schemenauer recommends using of a (2,2,1) network (viz. a network with two input, two hidden, and one output nodes) and the output is very much as desired, in the limits of errors of the ANN.

XOR Output for a (2,2,1) Back Propogation Neural Network;

([0, 0], '==', [0.025608579041218795])
([0, 1], '==', [0.98184578447794768])
([1, 0], '==', [0.98170742564066216])
([1, 1], '==', [-0.021030064439813451])

However, playing around with the number of hidden layers has interesting results,

XOR Output for a (2,1,1) Back Propagation Neural Network;

([0, 0], '==', [0.0020536886211772179])
([0, 1], '==', [0.68437587415369783])
([1, 0], '==', [0.68413753288547252])
([1, 1], '==', [0.6856616998850974])

The output of (2,1,1) clearly confirms the XOR problem !

Increasing the number of hidden layers indiscriminately, leads to anomalous output.

As an example, XOR Output for a (2,25,1) Back Propagation Neural Network;

([0, 0], '==', [0.99999643777993841])
([0, 1], '==', [0.99999911082329096])
([1, 0], '==', [0.99999280130316026])
([1, 1], '==', [0.99999824824488848])

Anomalous behaviour comes into play from about 12 hidden nodes.

REFERENCES
(1) An introduction to neural networks

FIREFOX EASTER EGGS

2010-07-28T11:58:00.009+05:30

FIREFOX EASTER EGGS

In mozilla firefox type in about:robots and then see the magic unfurl !

ABRACADABRA ! .......

..... if you can handle surprises then try about:mozilla

MPLAYER !

2010-06-20T15:49:00.004+05:30

I will keep it short and simple ! I had never come across a movie player which is controlled - NOT by a GUI, but command line in the terminal window ! ..... and then I came across MPLAYER .

I guess using Unix/Ubuntu is a 'learning' experience !

HEART TO HEART

2010-04-28T10:07:00.036+05:30

HEART TO HEART

A very interesting mathematical recreation is to conceive coherent drawings using algebraic functions. Bezier curves are the authentic way to generate such computer graphics. Bezier came up with his genius in early 60s while designing automobile parts. Other popular means are Hermite curves and Splines.

Though effective, these means are involved and computationally demanding. However, sometimes by providence we do have sensible shapes made out from simple functions.

PLOTTING THE HEART IN MATLAB

I discuss plotting a heart using simple cardioid, polar plots and algebraic equations

(a) The simplest one

The simplest 'heart curve' is the cardioid. It is not truly a heart, however it looks somewhat similar to one.

(b) Polar plot

A polar curve given by;

gives a near perfect heart !

The Matlab command line is;

>> ezpolar('((sin(t)*sqrt(abs(cos(t))))*(sin(t) + (7/5))^(-1)) - 2*sin(t) + 2')

(c) Algebraic Equation

A heart can be made from the implicit algebraic function,

However tinkering by adding a factor of (0.35) and (1.3) to the terms makes the heart more aesthetic.

The Matlab command is,

>> ezplot('(0.35)*((x^2 + y^2 - 1)^3) - (1.3)*(x^2)*(y^3)');

It is worth noting that for using ezplot t, x and y doesn't have to be defined.

(d) Another Algebraic Equation

This one is due to Matt ....

.
.
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...then again forget MATLAB, we do have <3 to our rescue !

REFERENCES
(1) ezplot
(2) stackoverflow question 2720180
(3) stackoverflow question 323584
(4) Heart Curve page
(5) Wolfram page
(6) Bezier Heart in Gimp

A VERY SIMPLE CHATBOX IN PYTHON

2010-04-19T15:22:00.015+05:30

A VERY SIMPLE CHATBOX IN PYTHON

A naive chatbot program. No parsing, no cleverness, just a training file and output.

It first trains itself on a text and then later uses the data from that training to generate responses to the interlocutor's input. The training process creates a dictionary where each key is a word and the value is a list of all the words that follow that word sequentially anywhere in the training text. If a word features more than once in this list then that reflects and it is more likely to be chosen by the bot, no need for probabilistic stuff just do it with a list.

The bot chooses a random word from your input and generates a response by choosing another random word that has been seen to be a successor to its held word. It then repeats the process by finding a successor to that word in turn and carrying on iteratively until it thinks it's said enough. It reaches that conclusion by stopping at a word that was prior to a punctuation mark in the training text. It then returns to input mode again to let you respond, and so on.

It isn't very realistic but I hereby challenge anyone to do better in 71 lines of code !! This is a great challenge for any budding Pythonists, and I just wish I could open the challenge to a wider audience than the small number of visitors I get to this blog. To code a bot that is always guaranteed to be grammatical must surely be closer to several hundred lines, I simplified hugely by just trying to think of the simplest rule to give the computer a mere stab at having something to say.

Its responses are rather impressionistic to say the least ! Also you have to put what you say in single quotes.

I used War and Peace for my "corpus" which took a couple of hours for the training run, use a shorter file if you are impatient...

here is the trainer

#lukebot-trainer.py
import pickle
b=open('war&peace.txt')
text=[]
for line in b:
for word in line.split():
 text.append (word)
b.close()
textset=list(set(text))
follow={}
for l in range(len(textset)):
working=[]
check=textset[l]
for w in range(len(text)-1):
 if check==text[w] and text[w][-1] not in '(),.?!':
     working.append(str(text[w+1]))
follow[check]=working
a=open('lexicon-luke','wb')
pickle.dump(follow,a,2)
a.close()

here is the bot

#lukebot.py
import pickle,random
a=open('lexicon-dict','rb')
successorlist=pickle.load(a)
a.close()
def nextword(a):
if a in successorlist:
 return random.choice(successorlist[a])
else:
 return 'the'
speech=''
while speech!='quit':
speech=input('>')
s=random.choice(speech.split())
response=''
while True:
 neword=nextword(s)
 response+=' '+neword
 s=neword
 if neword[-1] in ',?!.':
     break
print response

You tend to get an uncanny feeling when it says something that seems partially to make sense. I think this is a universal syndrome with chatbots and shows us a lot about our expectations and hopes for machine intelligence. The tendency to attribute some kind of surreal cosmic wisdom or irony to the responses is common.

TALKING TO TOLSTOY ! ...... ;)

Sample output:( is this like talking to Tolstoy? Not really but still...)


>>>
>'hello'
the human affairs he thought.
>'oh those affairs were great'
God,
>'what -surprised?'
do you value but she is what had the new country,
>'i do value but i do not blame the war on her'
so alarming them with those around with particular chair by all those who caressed me.
>'i never get anyone caressing me!'
allowed to talk about in a really so.
>'oh do not be prudish I am allowed to mention it'
should she suddenly heard of a duty for reason was handed him very hot.
>'you like these women a lot to talk about them so much'
advantage if your father?
>'my father approves of my romantic side'
love my son's having obeyed in the causes historic events that circle they didn't you know a force producing two Emperors with a certain prince.
>'oh now it is princes is it'
God,
>'do you believe in Him?'
the insistence of incongruities giving you married at his squadron--that is,
>' i don't understand you sir'
>'i do not understand you sir'
the bridge which,
>'i crossed'
himself,
>'ok ok... well 71 lines still is not bad'
the work at Smolensk?
>'yes'
or that of War.
>'no, war'
was gradually that millions of married in which is Dolokhov?

REFERENCES

(1) Pythomism - Luke's website

RANDOM NUMBER GENERATOR !

2010-04-11T14:46:00.008+05:30

RANDOM @DILBERT

RANDOM @NEUMANN

"Any one who considers arithmetical methods of producing random digits is, of course, in a state of sin. For, as has been pointed out several times, there is no such thing as a random number — there are only methods to produce random numbers, and a strict arithmetic procedure of course is not such a method."

-- John von Neumann

SINC LOOKS LIKE DIRAC DELTA

2010-04-10T11:10:00.001+05:30

DABBLING IN MATLAB

After installing Matlab R2009b (7.9.0) on Ubuntu Karmic, I was trying out many thing ! ...... just for fun ! While trying out sinc function .... at a certain point it resembled dirac delta !
.
.
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One very long spike unto infinity !

REFERENCES
(1) Delta Function
(2) Sinc - Delta Relationship

THE ASCII TRAIN !

2010-03-25T22:03:00.008+05:30

FOOLING AROUND @ UBUNTU 9.10

Every coder sometimes or the other, looks for a lighter moment and Ubuntu has plenty of those. One such instance .....

Install 'sl' using sudo apt-get install sl. Then, type sl in the terminal ! and watch the ASCII Train !

MOO .....

2010-03-13T08:33:00.011+05:30

ON THE LIGHTER SIDE !

#1. MOO

In Ubuntu 9.10, while trying the command sudo apt-get moo ! ...... there is sure some surprise in store.

#.2 COWS ..... FROM OUTER SPACE !

Whoever put these easter eggs into Ubuntu (9.10) was sure some cow sympathiser !

Try this ..... Alt + F2 + 'gegls from outer space' + enter !

Voila ! ..... the 'gegls' !

JYTHON : FIRST CONTACT !

2010-03-04T14:41:00.010+05:30

JYTHON, MARRIAGE OF JAVA AND PYTHON

Trying my first shot at Jython, using java swing in python-like interactive interface !

CHECKING FOR SQUARES !

2010-03-04T13:47:00.006+05:30

AN ELEGANT CODE IN PYTHON !

This program confirms if a number is square or not !

SEMAPHORES IN ADA

2010-02-27T11:04:00.030+05:30

THE PROBLEM OF SYNCHRONISATION

Often there are occasions when events must happen in a certain order ! specifically ....

(1) Serialisation: Event A must happen before Event B.
(2) Mutual exclusion: Events A and B must not happen at the same time.

In concurrent programming every process is fighting for time and resource thus in perspective of the above, order must be restored to this apparent chaos. One rather interesting way is to use semaphores.

Semaphores were invented by the Dutch computer scientist Edsger Dijkstra (EWD 74).

A definition will be, a non-negative integer-valued variable that can only be acted upon by two procedures: sem_wait and sem_post

These operations are defined (for a semaphore s) as:

sem_wait(P)
if s>0 then set s:=s-1 and allow task to proceed else suspend task

sem_post(V)
set s:=s+1

For a synchronisation where each process waits for the other, synchronous synchronisation will be done using 2 semaphores, as;

TRYING IN ADA 2005

Trying the scenario in Ada 2005, where Task A and Task B are defined as

Task A : printing 'A' 5 times
Task B : printing 'B' 5 times

yields the following results, the output strictly interleafs on all ocassions,

however the slicing is of 2 rounds of each task at a time.( i.e. 'AA' , 'BB' ....). This slicing can be tailored with scheduling policies.

REFERENCES
(1) Concurrent and Real Time Programming in Ada
(2) Semaphore construction
(3) http://code.google.com/p/ada-simple/

HELLO WORLD IN ADA 2005

2010-02-27T08:44:00.001+05:30

HELLO ADA !

I should not be writing this article ! ...... however, trying out very simple programs in Ada 2005 made me realise how I have lost touch of the syntax etc !

Ada is a high level language which is a favourite for safety critical and real time systems. Trying out the 'Hello, World' in Ada,

The syntax has a 'pascal like' sing to it, Ada program files have extensions adb or ads. The compiler used for Ada is GNAT (which is a part of gcc).

Compilation creates 3 more files.

Running the program,

A SIMPLE EXAMPLE WITH PYCHECKER

2010-02-22T19:17:00.015+05:30

BEGINNING TESTING !

Trying out this tool for python testing .... pychecker on program e.py,

The testing software identifies that sum 'shadows builtin' , thus changing name of the function from sum to summation.

.... rectifies the Warnings !

REFERNCES

(1) Pychecker
(2) Beginning Python : From Novice to Professional

DABBLING WITH BASH -1

2010-02-19T10:35:00.042+05:30

DABBLING WITH BASH - 1

BASH (Bourne Again SHell), the name seemed to echo between 'Bashing' to 'Bourne Trilogy'. The command line for nearly all *nix Operating Systems is actually a programming language !

I am working on version 4.0.33

1)The Hello World Program

1a) from command line

1b) from script

1c) 'Exotic' Hello, World(s)

This program prints Hello and the first command-line argument

2)Counting from 1 to 10

3)Evaluating the squares

4)Some Arithmetic

CHECKING FOR OPENGL RENDERING IN UBUNTU

2010-02-14T23:49:00.009+05:30

CHECKING FOR OPENGL RENDERING !

Details about rendering and also the graphics-card can also be obtained by the command, glxinfo | grep render

4 GOOGLE SEARCHES IN A SINGLE PAGE !

2010-01-08T22:40:00.015+05:30

Try "www.googlegooglegooglegoogle.com" and get the 4 google search on a single page.

Try playing with funny variations ! a mix and match with wiki and google !

ZETA IN SCIPY

2010-01-04T06:30:00.018+05:30

PROBLEMS WITH ZETA FUNCTION IN SCIPY

Dabbling with zeta in scipy gave various unsatisfactory results. Few very obvious results of zeta function are ;

(1) For negative even integers the function is zero

(2) zeta(0) = -1/2

(3) zeta(-1) = -1/12

(4) zeta(1/2) = -1.46035450880.....

(5) zeta(1) = infinity

(6) zeta(2) = 1.6449340.....

Trying it on scipy,

The probable reason for this inconsistent behaviour and issues for zeta values below 2 and improbable results for negative numbers is; the module is probably structured abinitio from zeta function

whilst it may be a better idea to structure the zeta function using the functional equation.

It may also help to have a special provision for zeta(1/2)

REFERENCE
(1) Zeta Scipy reference

AN EXPERIMENT IN ADA

2010-01-04T05:43:00.025+05:30

MULTIPLE CONCURRENT UPDATES IN ADA-2005

Probably the best book in Ada concurrent and real time programming is,

Pic 1. Concurrent and Real time programming in Ada-2005

In this book, in page 37 the authors discuss a program which lacks protection to multiple concurrent updates,

Pic 2. The Program

On tinkering with the program, increasing the looping; strange results are seen to happen. The program is tried with increasing looping in XP and also Ubuntu 9.10. The results are as follows;

Observations in XP ( first table ) and in Ubuntu 9:10( second table ) :

The program runs on the same body and has 2 tasks, on higher loops discrepancy is observed and issues of multiple concurrent updates are visible.

On closer observations it can be seen that XP and Ubuntu 9.10 behave little differently and the issue of multiple concurrent updates come to be at different loopings.

The reasons for such behaviour is still not very well understood by me, however modifying the program using semaphores does rectify this problem.

STARTING OFF IN RUBY

2009-12-27T07:24:00.006+05:30

MY FIRST RUBY PROGRAM !

Dabbling in python and its variants I came to try ruby ! The syntax is very similar to python.

Fig1. Ruby version 1.8.7

My first program was straight from the ruby website,

Fig2. Seen on Ruby website

The output was as desired !

Fig3. I love Ruby !

SINE INTEGRAL IN SCIPY

2009-11-27T01:59:00.003+05:30

THE SINE INTEGRAL

The Sine Integral is a very important function in Physics, Astronomy, Electrodynamics, Mathematical Physics,Optics and Signal Processing.

A fundamental result in the sine integral is;

This result is analytically proven using contour integrals concept from complex theory.

TRYING IT IN MATLAB

MATLAB gives excellent results, particularly for the special case of (0-inf )it gives correct value.

TRYING IT IN SCIPY

In Scipy the sine integral (and the cosine integral) is via (si,ci) = sici function. It yields excellent values for numbers, however for infinity it yields nan (not a number). This should probably be corrected with an exception in the sici module.

It is worth noting that for sufficiently high values (which tend to infinity) the desired result of 1.57.... ( = pi/2) is obtained, which confirms the numerical evaluation is correct

REFERENCES
(1) sici
(2) sine integral

RAISING IT TO THE POWER OF ......

2009-11-25T06:23:00.016+05:30

LAWS OF EXPONENT

In the laws of exponents, a number can never be raised to an exponent to yield negative values. Only using complex exponents can negative values be obtained.

Trying the same formulation in python, it is worth noting that the formulation fails for a = 1 hence a special case output for a = 1.

Some sample output is ;

Similar treatments in MATLAB is also fruitful

The visible change is that iota in MATLAB it is i, while in Python it is j.

BIZARRE BIZARRE PYTHON

2009-11-07T16:29:00.004+05:30

IS THAT SOME WITCH CRAFT ?

Python .... maybe the one of the best programming languages has just gone crazy !

In the interpreter mode I got these crazy results trying to get numbers starting with zero...

Only on referring to Hetland that I got to know that the interpreter does an OCTAL !

REFERENCES
(1) Hetland

SQUARE ROOT OF IOTA

2009-10-19T05:49:00.024+05:30

SQUARE ROOT OF COMPLEX NUMBERS

i, the square root of -1 the fundamental complex number. Working out the square-root of i;

ON MATLAB

Trying it on Matlab

Fig 1. Matlab 1

Fig 2. Matlab 2

Matlab gives very precise result both by 'power of 0.5' and 'sqrt function'.

USING CMATH

Using cmath module in Python;

Fig 3. cmath 1

Fig 4. cmath 2

cmath also gives wonderful results, however it is worth noting that the real and complex parts are different in the last 2 digits ( 0.70710678118654757 in the real part while 0.70710678118654746 in the complex part); which should not be so as they both represent the same number ! 

USING SCIPY

Using Scipy, scientific and numerical module in python

Fig 5. Using Scipy

EULER'S GAMMA !

2009-10-11T04:16:00.023+05:30

EULER'S GAMMA

Once again ! .... we meet Leonhard Euler ... a constant named after him. Euler-Mascheroni constant which runs as .... 0.57721 … called 'gamma' ,denoted by the Greek alphabet 'gamma' and is one of the important constants of mathematics.

From an abinitio, 'gamma' is defined as;

IN SCIPY

Trying it out in scipy yields a very accurate gamma.....

Fig 1. gamma in scipy

Should gamma be build into scipy as pi and e ?

Fig 2. pi and e in scipy

IN MATLAB

Trying it in MATLAB

MATLAB recognises the integral as a special integral ! ...... with a vpa, the value is obtained.

Gamma and other mathematical constants should be build into Scipy and Scipy should be intelligent enough to identify these expressions and integrals.

REFERENCES
(1) Murray Spiegel

AN EXOTIC INTEGRAL IN SCIPY

2009-10-01T22:57:00.018+05:30

ADVENTURES IN SCIPY

Scipy is a module in python which allows for mathematical and scientific functions and tools. Trying to evaluate an exotic integral , using contour integration and complex analysis it can be shown that ;

Trying out the integral in scipy, the function is introduced using lambda and the scipy.integrate.quad is used over 0 to infinity to obtain the results. The result comes up with a warning on infinite recursions and a recommendation to use a special-purpose integrator and the numeric value is 1.5708678849453777, which is with 0.0015587759422623915 of the correct value (~0.025% accurate).

Fig 1. The integral in scipy

REFERENCES
(1) Scipy
(2) Scipy mini anthology

I AM FAMOUS !

2009-09-20T16:55:00.007+05:30

GOING PLACES ..... AGAIN !

Now, I am famous ! ...... my game Pygame Toss has been published in famouswhy ..... I would guess it is the simplicity of the game than its achievements , that makes it 'famous' !

Fig 1. I am famous !

REFERENCES
(1) Pygame Toss

VISUAL PYTHON

2009-09-19T17:38:00.016+05:30

VPYTHON - FIRST PROGRAM !

Trying out visual python (version 5.12) came rather easy.

My first program was mere 2 lines and I could do a fair deal with that.

REFERENCES

(1) VPython intro
(2) Some great examples
(3) Wiki
(4) Vpython in teaching Physics

AN ODE TO 'pi'

2009-09-17T18:20:00.021+05:30

3.141592653589793......

The ratio of circumference to diameter, may be no other number has intrigued and troubled mathematicians any more. The Bible puts pi as 3 ..... while many fanatics have spend the prime of their lives computing the 'little' that lies beyond 3 ... Ludolph van Ceulen from Leiden is sure worth a mention .... and he took the 35 digits of his computation to his tombstone after his death in 1610 ..... the exoticism of pi doesn't end here ..... and Feynman point is another interesting aspect of the unending digits of pi....

It must be appreciated that pi is not just another constant .....and is far from the likes of physical constants as G,h and c ..... and is also distinctly different from root 2, gamma, e and iota .... the physical constants are structured by the physical theory and are found to vary with time..... while e, iota, gamma etc can be said to be product of our chosen number system and the bias of our prevalent mathematical structure ....... while, pi is engraved in mother nature ..... it is ubiquitous and omnipresent .... pi enunciates why every circle mimics every other circle .... and so is true for every sphere..... Various physical theories as electrostatics, fluid-dynamics and gravitation have confirmed the presence of pi in their formulation , i.e: Stokes Equation, Gauss's Law, Kepler's law .....

The only other constant which may compete for similar prominence is phi , though phi is more subtle and not really as often visible as pi .... well..... I must stop with these rhetorics ... and get to business ...... 2 python recursions (1) Ramanujan's formulation (2) Wallis Product.

(1) Ramanujan's formulation

One of the most exotic and 'very fast converging' series for computing pi was given by Ramanujan...

A corresponding python program is ....

Fig 1. piramanujan.py

The program gives very accurate value of pi (3.14159265381), however the limit of recursion is reached in about 20 terms ...

(2) Wallis Product

An evaluation of pi in a 'product' form of an infinite series was given by English mathematician John Wallis.

The python program is ....

Fig 2. piwallis.py

The limit of recursion is at about 995 terms .

Though life can be made much easier ... away from these recursions by importing pi from math .....

Fig 2. pisimple.py

PYTHON RECURSIONS FOR 'pi' AND 'e'

2009-09-16T21:25:00.017+05:30

FROM THE BASEL PROBLEM

The problem which put Euler on the path of immortality was the BASEL PROBLEM solved in 1735, 91 years since it was proposed . Succinctly put Euler's proof was ;

Using this result to obtain a recursion for pi in Python !

Pic 1. pi.py

At 500 terms the result is 3.13968..... not too far from the sinister 3.1415.....The recursions are good till about 995 terms (3.14063326091) after which one comes across .... RuntimeError: maximum recursion depth exceeded

Similar programs may be devised on more series as given by Euler, as .....

RECURSIONS FOR e

e the base of natural logarithm is yet another important constant in mathematics .... and once again related to Euler .....

A python program on this recursion is designed via the factorial function ....

Pic 2. e.py

The limit of recursion is around n = 170 which yields a very accurate value of e.

Thus in a nutshell .....

"Read Euler, read Euler, he is the master of us all."

-- Pierre-Simon Laplace

REFERENCES
(1) Recursive functions for phi and root two
(2) Other pi recursions in Python

STARRY THINGS !

2009-09-16T20:19:00.005+05:30

ONCE UPON A STAR LIT SKY

I discuss 2 programs which try to mimic stars in the sky.

Program 1 (stars.py)
This program comes along with examples in the official pygame package , very nice introductory example. With every mouse click the supposed center of the screen moves to that point. Creates a good illusion and can be used as the start-up for further futuristic starry games and animations.

Video 1. Program 1

Program 2 (parallaxstars.py)
I came across this example from Chapter 8 of Will's book, this example creates an illusion that the stars close to the observer are moving faster than those in the background, unlike last example ... a mouse click does no good to the program ! once again a good program and can be used as background for futuristic games.

Video 2. Program 2

It is worth nothing that both these Pygame GUI's generate random stars and does not use any images to blit the screen.

CODEPAD

2009-09-07T21:37:00.013+05:30

....AND THEN THERE WERE ALL ..... !

Other than Netbeans, Scite and Eclipse there is hardly another IDE which supports a wide array of languages

! VOILA ! ..... CODEPAD ..... AN ONLINE COMPILER / INTERPRETER FOR 12 LANGUAGES

Python works cool , but lacks the interpreter mode. Another online interpreter specifically for Python is Try Python which preserves the Python Chevron (>>>) and is in the interpreter mode. Zamplizer is another multi-lingual online platform.

Fig 1. The pad of codepad

Fig 2. Simple Ruby code in codepad

REFERENCES
(1) My codepad profile
(2) Online Compilers
(3) The Ruby code

FERMAT'S LAST THEOREM !

2009-09-06T06:10:00.012+05:30

FERMAT'S LAST THEOREM !

Allen Downey in his book Think Python poses the reader with a problem !

Write a function named check_fermat that takes four parameters — a, b, c and n — and that checks to see if Fermat’s theorem holds.

Fig 1. Fermat's last Theorem

A suitable program may be made as;

Fig 2. Python Code for check_fermat

However, it must be noted that this sort of treatment may never form some basis of an alternative proof of Fermat's last Theorem, which was the holy grail of mathematics till 1995 when A ndrew Wiles established the proof for the 358 year old puzzle.

REFERENCES
(1) Simon Singh

PALINDROMES !

2009-09-06T05:31:00.010+05:30

PALINDROMES !

A simple program to check for palindromes .

Fig 1. The code for palindrome check

Fig 2. Sample output

REFERENCES
(1) Allen Downey
(2) Palindromes
(3) Palindromes of numbers

TAXICAB IN PYTHONLAND

2009-08-31T00:31:00.015+05:30

THE TAXICAB NUMBER Ta(2) TYPES

The Taxicab Numbers Ta(2) types are expressed as,

The name is attributed to a historical discussion between Ramanujan and G.H Hardy.

"I remember once going to see him when he was lying ill at Putney. I had ridden in taxi-cab No. 1729, and remarked that the number seemed to be rather a dull one, and that I hoped it was not an unfavourable omen. "No", he replied, "it is a very interesting number; it is the smallest number expressible as the sum of two [positive] cubes in two different ways."

--G.H Hardy

1729 is the smallest Taxicab Ta(2) number and can be expresses as cubes of 2 different sets of numbers (12, 1) and (10, 9).

A Python program for generating such numbers placing range conditions on a,b,c, and d yielded

as the highest Taxicab Number for a,b,c,d in the range of 1 to 100 and

for a range from 1 to 1000.

The crux of the Python program is obviously summed up as;

REFERENCES
(1) Taxicab Numbers
(2) Source code

A COMMON ERROR IN PYTHON !

2009-08-30T20:27:00.008+05:30

= AND ==

A common error in Python is a mix-up of == and = , this example illustrates this

Fig 1. The mix up !

Fig 2. The solution

Fig 3. Moral of the story

REFERENCE
(1) Allen Downey, ' Think Python'

HELLO HASKELL !

2009-08-24T17:28:00.012+05:30

HELLO WORLD

Seems I am into some 'Hello World' frenzy !. The Haskell 'Hello World' is similar to that of Python .

Fig 1. Hello Haskell

REFERENCES
(1) Haskell in 5 easy steps

HELLO ANDROID !

2009-08-23T21:58:00.009+05:30

ANDROID

Android is a Google platform for mobile devices. IDE Eclipse allows for the Android plug in and the programming is in Java.

Fig 1. Android Logo

The 'Hello World' program was indeed some struggle, not because of the code but rather since one has to wait for about a minute as the emulator executes the program.

Fig 2. Hello Android

Fig 3. Hello Android code

Fig 4. 'Home' in the emulator

Fig 5. 'Hello Android' in the menu

Fig 6. The blog spot

REFERENCES
(1) 'Hello World' files
(2) http://www.android.com/
(3) Eclipse

2+2 = 4199232

2009-08-17T05:37:00.019+05:30

2+2 = 4199232

If only C++ was not so notorious !

Fig 1. 2+2 = 4199232

Trying out this simple program in Quincy gives a weird output !

What is happening is that, The printf statement: printf("The answer is %d\n"); tells the program to print an integer, but fails to supply one. The printf function doesn't know this, so it will take the next number off the stack (some random number) and print it.

The correct code should be: printf("The answer is %d\n", answer);

Fig 2. Corrected Program, 2+2 = 4

Running the program in Unix (Ubuntu) gave another result ! 2+2 = 134518880

Fig 3. 2+2 = 134518880

REFERENCES
(1) Oualinne, Steve "How not to Program in C++", No Starch Press 2003
(2) Quincy

MY PROJECT LOGO

2009-08-13T03:04:00.007+05:30

MY PROJECT LOGO !

Now ! ..... to stamp my mark on my projects, I had to think of something ! ...

This logo has a 60s looks to it !... but looks snazzy ! .... this logo can be seen on top left of all my google-codes pages !

Fig 1. My Personalised logo

HOW DID I GET A SOFTPEDIA PAGE ???

2009-08-06T16:25:00.009+05:30

I JUST DO NOT KNOW !

I had uploaded my recent game PIRATE SLOT MACHINE 1.1 on google codes with links on Pygame page ! ...... and voila I now have a softpedia advertisement ! ..... seems open source goes places .... all across the web!

Pic1. How did it happen ??

Fig2. It keeps getting weirder !

REFERENCE
(1) Softpedia page 1 !
(2) Softpedia page 2 !

PIRATE SLOT-MACHINE

2009-07-31T04:23:00.023+05:30

PIRATE SLOT-MACHINE

Another game of chance with Pygame ! with a piratey touch to it ! The tokens used in the slot machine are (1) The Jolly Roger (2) Pirate mate (3) Anchor (4) Treasure-map and (5) Gun.

5 Tokens , 3 slots ! ......

Fig1. Randomisation is achieved with 3 variables

May be the best game of chance I have made , the obvious thread can be traced to Pygame Dice and Pygame Toss discussed here earlier.

Fig2. Start-up screen

Fig3.User-Input Screen

Fig4. 'Loser' Getting all 3 different tokens

Fig5. 'Good Job' Getting at least '2' similar tokens

Fig6. 'Winner' Getting all '3'

Video1. Pirate slot-machine

REFERENCES
(1) Pygame Project 1243
(2) Source code

PYGAME DICE

2009-07-19T18:56:00.016+05:30

PYGAME DICE

Extending the idea of tossing a coin to the throw of a pair of dice. The throw doesn't have equal probable events , ie: Probability of getting a cumulative sum of 10 is not the same of getting a cumulative sum of 7.

The probabilities of rolling a cumulative sum of 'n' is maximum for rolling a 7 (16.67% , lucky seven) while it is the lowest for rolling a 2 or 12 (2.78%).

To allow the user to have the 12 choices (2-12 and Quit) two variables are used as posx and posy (single variable pos used in the toss of a coin), to make a grid.

Fig1. The start up screen

Fig2. The user interface

Fig3. The Result screen (1)

Fig 4. The Result screen (2)

The coding gets lengthy due to the 36 possible outcomes of the event. The lines of codes tally to nearly 1450 across 2 python files.

It is worth noting that throw of a single die is an equal-probable event with all events bearing a 16.67% probability thus programming such an interface would be lot easier and just matter to add on to the toss of a coin code.

Video 1. Pyagame Dice

REFERENCES
(1) Pygame project 1287
(2) Softpedia Award

MY TRYST WITH DJANGO - Part 1

2009-07-18T15:00:00.004+05:30

THE BEGINNING

Something very conspicuous about software and programming languages are that they are named in rather peculiar manner. Sometimes it is a play of words as WINE (Wine Is Not an Emulator) and XNA (XNA is Not Acronymed) to those named after some scientist or mathematician as Ada, Turing, Pascal etc , then there are also those named after some entertainment/cartoon character as Linda (allegedly named after porn star Linda Lovelace) , Python (named after the comedy group Monty Python) and Django (named after jazz guitarist Django Reinhart).

Fig1. The British comedy group Monty PYTHON

Fig2. Jazz Guitarist DJANGO Reinhardt

DJANGO 1.0

An open source web development tool , developed in 2005 for maintaining news websites for The World Company , Lawrence , Kansas.

Versions 1.0 and higher , released in early 2009 has been lot different than the previous version of 0.96.

Just to check everything is in order ..... check the django version and django-admin must be on the path !

Fig3. DJANGO version in python shell

Fig4.'django-admin.py' must in the path

'IT WORKED !'

After the efforts , it is soothing to see the pastel blue 'IT WORKED'

Fig5.First Django page

HELLO WORLD

Hello World and time is made modifying the views and urls file.

Fig6. 'Hello World'

Fig7.Time in Django , refreshing the screen updates the recent time

Fig8.'Hello World' and 'Time'

Fig9.Error 404 , the http://127.0.0.1:8000/ is no special page

REFERENCES

2 references used by me are ,

(1) The Definitive Guide to Django , 2nd Edition

(2) Django 1.0 WebSite Development

STARTING WITH GAMEMAKER 7.0

2009-06-25T03:54:00.028+05:30

GAMEMAKER 7.0

I got inspired to try out GAMEMAKER 7.0 after skirting through the wonderful book by Jacob Habgood and Mark Overmars.

Fig 1 . The Game Maker's Apprentice

GAMEMAKER reduced the 'coding' aspects and allows creation of games using GUI. Excellent software ! in some beginnner's pursuit I was able to create game snippets similar to PAC-MAN and SUPER-MARIO. The software is also supported by GAME MAKER LANGUAGE (GML) which is similar to Java/C++.

Fig 2. Game snippet similar to SUPER-MARIO. The 'mushrooms' add life and energy whilst the 'snakes' reduces it.

Video 1. Game snippet similar to SUPER-MARIO

Fig 3. GML 'Hello World'

Fig 4. GML 'Hello World' script

REFERENCES

(1) Jacob,H & Overmars,M 'The Game Maker's Apprentice'
(2) GAMEMAKER SITE
(3) http://gamemakerblog.com/
(4) youtube tutorial

THE TOSS IS ALWAYS IMPORTANT !

2009-06-21T19:17:00.044+05:30

MY FIRST INTERACTIVE GAME : PYGAME TOSS

My first interactive user input game ! .... tossing a coin. The user is prompted to choose (HEADS or TAILS) using the up and down keys ,and enter.

Fig1. Start up screen

Fig2. User input screen

An Intermediate screen confirms the choice made by the user.

Fig3. Intermediate screen confirming the user of his/her choice

The Result of the toss is confirmed by the show of the successful side of the coin and status (Winner/ Loser) in regards to the user's choice.

Fig4(i). Result screen

Fig3(ii). Result screen

THINGS WORTH A CHAT

(1) The randomisation is realised using the random module across a range (1,2)

Fig5. Randomisation

(2) The Disney font is used to give a touch of humour
(3) The PyGame screen is (512 x 384) suited for a small game !
(4) Dr.Python is WOW ! better than Scite

THINGS NOT WORTH A CHAT

(1) There should be a 'count' which counts the number of times 'you' win.
(2) I am avoiding all sound effects since they fail with py2exe.

Video 1. PyGame Toss

Such codes can be extended to any more games of chance as a throw of a die, draw of cards etc.

The user-input setting can be used to make an electronic photo album or an electronic jukebox.

REFERENCES

(1) http://www.pygame.org/project/875/
(2) Mc Gugan,Will ' Beginning Game Development with Python and Pygame'
(3) IYOCGwP
(4) Source code and images , http://code.google.com/p/pygame-toss/downloads/list
(5) Pygame Official Project 1254

WHAT IS PYGLET ?

2009-06-20T20:01:00.015+05:30

WHAT IS IT ?

It is a cross-platform , Open-GL based software library used for developing games and animations using python.

Image 1. '...snakes.....pigs ....it is an entire zoo out here...'

The improvement over PyGame is that it allows animated gif images.

Video 1. Create Space Invaders with Pyglet in 40 Minutes

Video 2. Animating a gif file

REFERENCES
(1) Wikipedia page
(2) Daniweb , http://www.daniweb.com/code/snippet853.html
(3) Pyglet website , http://www.pyglet.org/

21 POUNDS

2009-06-15T03:35:00.023+05:30

21 POUNDS

A 1 pound coin bouncing randomly with a 20 pound note in the background ! Another PyGame creation !

Fig 1. 21 Pounds

Fig 2. 21 Pounds

Fig 3. 21 Pounds

OBSERVATIONS AND THE CODE

The code is somewhat different than my earlier PyGame creations. Further, there is a parameter 'e' to slow down the speed of the 1 Pound coin. At e = 0.98 the 1 Pound coin comes to a stop after about 141 seconds , at the upper left corner of the pygame screen. For e = 1 , the coin never comes to stop while for e > 1 , the motion becomes faster and erroneous and the software rejects it after some time.

Video 1. 21 Pounds

The PyGame screen is also made to suit to that of the 20 pound note (591 x 326) and not the usual (640 x 480).

Fig 4. 21 Pounds , the code

It is also worth noting that random motion is obtained without the use of the random module.

REFERENCES

(1) Daniweb , http://www.daniweb.com/code/snippet758.html
(2) source code and images , http://code.google.com/p/pygame-21pounds/downloads/list

MAKING A FIRE !

2009-06-05T04:17:00.023+05:30

PYGAME FIRE

Trying to animate a fire , using python game platform , pygame. I got the fire 'to life' by combining together 16 different sketches or 'sprites'. The primary plume and the wood being the static parts while the other smaller portions of the flame being in repetitive motion. Black is used as background for best contrast.

Fig1.Fire, Screen-Shot 1

Fig2. Fire , Screen-Shot 2

Superimposing the main plume with 14 other minor plume allows creating a seeming movement of the flames upward.

Fig 3. Without the main plume (14 minor plumes and the wood)

Video 1. PyGame Fire

The 'effect' is created by motion of the 14 sprites both in horizontal and vertical axis and the variation of the colour. Not often 16 different pieces are sewn together to form an animation in PyGame.

Some tweaking has to be done with the various parameters in order to 'liven-up' the fire.

REFERENCES

(1) Source code and sketches , http://code.google.com/p/pygame-fire/downloads/list

CHERRYPY : HELLO WORLD

2009-06-01T03:08:00.025+05:30

HELLO CHERRY

CherryPy is a python based web-development tool. The traditional 'hello world' is scripted as follows.

Fig 1. 'Hello World' in CherryPy

After running the program , on opening http://localhost:8080/

Fig 2. In Firefox

Fig 3. In Safari

REFERENCES
(1) CherryPy Website

THE TRAIN : MY FIRST VISUAL IN PYGAME

2009-05-28T00:17:00.057+05:30

THE TRAIN
My first visual in PyGame ! THE TRAIN ! .....

Fig 1. PyGame , Game Development in Python

One of the first motion pictures was 50 second screening of a train , I took a leaf out of that. My first visual in PyGame is a train passing through a field with birds flying away in the sky.

The visual was made using 4 sketches or rather 3 'sprites' , One for the train , One for the setting and 2 for birds in either directions. The sound effects were my efforts to record train sounds from the London Underground and also the Southern Rail , and then painfully converting them to ogg files.

Fig 2. Screen-shot 1

Fig 3. Screen-shot 2

Video 1 .The Train

THE GOOD BITS !
My first efforts yielded some success !

(1) The train moves !
(2) The birds in both the directions gives a more realistic effect !
(3) 3 movements incorporated in the same scene !
(4) The sound effect was icing to the cake
(5) All of it , from conceptualisation to realisation was mere 4 days !

WHAT REMAINS TO BE DONE !
(1) The train 'glides through' I wish I could make the wheels to go round
(2) It is all too sketchy , B/W ! needs some glamour !
(3) The sound is not in sync with the train's movement
(4) Lack of an user input !
(5) All looks a bit kiddish !

THE CODE
No programming discussion is ever finished without the code !

The code is a single python program (train.py) , available in Reference (2) .

REFERENCES
(1) Mc Gugan,Will ' Beginning Game Development with Python and Pygame'
(2) Source code , sketches and sound can be downloaded from http://code.google.com/p/pygame-train/downloads/list
(3) MARIO
(4) Pygame project 1380

CONCURRENCY AND WINDOWS DO NOT MARRY !

2009-05-24T05:01:00.039+05:30

THE UNFAITHFUL MARRIAGE !

WINDOWS does not support multithreading concurrent and real-time structures. What an irony !.The most popular OS does not allow systems and structures which can control the most breathtaking technologies of the day. Aerospace , trains, nuclear power plants and other state of the art embedded technologies cannot use WINDOWS !

When I learned about Real-Time and Concurrent Systems ,it was not very acceptable that Microsoft would make such a redundant OS. A bit of dabbling on the internet led me to Article Number 22523 in Microsoft knowledge base.

Fig1. Article 22523

Which clearly stated that ,

"In no sense can Microsoft Windows be considered a "real-time" system. It is a message-driven, event-polling system, with nonpreemptive scheduling".

Being initiated in Windows and using it for about ten years , did make me stubborn and I tried to look for other alternatives which would allow to construct real-time structures in Windows.

Cygwin came to my rescue ! However on running threads in POSIX and tasks in Ada, I realised that it is only a cheap makeover.

Python and Ada however worked in windows , Ada because it is a concurrent language and platform is not an issue. Python did execute the threads , though on a closer inspection it revealed that Python reduces the concurrent codes to their sequential evil twin brother.

A simple code which which prints out 'Hello World' and the thread number ;

Fig 2. The threading code

gives slightly different results with different OS. When run on Ubuntu Linux ,

Fig 3. Execution in Ubuntu

The order of execution of the threads is 3,4,1,5,2 then 1,2,3,4,5 and then 5,4,3,2,1. Thus the order of execution is non-deterministic , typical of real-time systems.

However on Windows ,

Fig 4. Execution in Windows, 'evil twin brother'

the order of execution is deterministic , as seen above. Thus windows prevents the real-time characteristics of non-determinism and reduces it to sequential processes.

Linux confirms the standard characteristics of concurrency as nondeterminism and preemption , hence a joy for all concurrent programmers. Seems Bill Gates got it wrong this time !