Tuesday, December 31, 2013

You feel despair, you feel there is no point in taking another step.
You feel you don't have the energy to take another step.

But then you simply take another step,
and meaning comes, energy comes.

Tuesday, December 24, 2013

Hard to kill this crazy love I have for you,
anywhere in Europe I can hear you cry out,
for what we shared.

It seems like it will be a miracle for a whole continent
when we reunite.

Saturday, December 21, 2013

A brief history of the theory of computation

Somewhere in the beginning of the 20th century,
the notion of a computer was mathematically formalized.
(The name `computer' came from people whose job it was to perform mathematical
computations on a piece of paper - they were called computers)

It was asked first: Is there something a computer can't compute? Even
if it is given an unbounded amount of time and space to use?
Alan Turing showed that even in such a case a computer cannot solve the following problem:
You give it a code of some computer program and ask it: If I run this program will it go
on running forever? Or will it stop after some finite amount of time?
Turing showed that whatever program you write to answer this question, it will always
give the wrong answer on some computer program it gets as input.

But it seemed that pretty much any problem you would want to solve
you could write a computer program for.
So the next big question was: Out of the problems a computer *can* solve, are there problems it can't solve in a reasonable amount of time?
A good way to think of reasonable is : Suppose I give the computer an input to the problem that is 800 bits long. Then if it can solve the problem before the universe ends using just the resources inside the universe
then this is reasonable.

Using the Theory of NP-Completeness it was shown that the following problem probably cannot be solved in a reasonable amount of time:
We have a map with n cities. Between each 2 there is a train. We start in the first city.
We ask what is the fastest way to go through all the cities and return to the first one.
That is, in which way order should we go through the cities to minimize the total travel time.
This problem is called - The Travelling Salesman Problem - or TSP
But, alongside theory who said this problem is hard, on many of the maps and sets of n cities that people cared the problem was and is being solved in practice.
So, now the next big question: Characterize which instances of TSP can be solved in reasonable time and which cannot.
One example - suppose the n cities are located in log(n) different states that are very far away from each other. And furthermore, inside the states it is clear what the best route is. Then we can prove an efficient algorithm exists.

Friday, December 20, 2013

He was rational, open minded
but had the need to be a fanatic.

She would become his religion..
When they first met, they joked that she would be a cult leader
and he would be the most devoted member.

But it was no joke,
worshiping her was like a drug..
and he did not care about it's insanity..
as long as that feeling could make him do one more push up
work harder, run faster,
he thought.. as drugs go you could do much worse.

He wished she would become just as addicted to this insanity..
They would be so caught up into it, they would barely notice as their bodies
turned to dust..

It would not change for a moment the way they looked at each other..
even as only bones and skulls were left.

Thursday, December 19, 2013

It's spreading like wildfire! A big Israeli coffee chain has added a new vegan menu to all its branches after a survey indicated 40% of its customers were interested in more vegan options.


Wednesday, December 18, 2013

Most of the time we take for granted that Technology works..
and doing computer science research you take for granted most of the time
that mathematics works.
But there are moments when you feel how remarkable it is.
You look at a string of 0's and 1's.
For example (1,0,1,0,0,0,1)
And you look at all it's cyclic shifts (where you move all bits one place to the right and move the last one back to the start)
The first shift gives you      (1,1,0,1,0,0,0)
The second shift gives you (0,1,1,0,1,0,0)
and so on..
You would like to prove that the 1's of the different shifts intersect with the original string on at most one coordinate:
For example: The original string has a one on the 1,3,7 indices.
                     The first shift has a one on the 1,2,4 indices
       so indeed they intersect on only one place.
Can you prove the intersection is always at most of size one without checking?
It turns out the following thing works.
There are these things called Galois fields
which are groups of numbers that are different from regular numbers.
For example in the Galois field GF(8)  we have 1+1 =0. Also, as the name implies - we have only 8 different numbers in this field - rather than infinitely many as we are used to with rational or real numbers.
In this field GF(8) there are special elements called generating elements.
These are elements g with the property that when you take their powers g,g^2,g^3...
they will run over all elements in the field except the 0 element.
Now say we take such a generating element g and compute the polynomial
whose roots are the powers of g corresponding to the 1's of our string - 1,3,7
and also 0
That is the polynomial
It's easy to see this polynomial has degree 4.
What will be the coefficient of x^3?
It turns out that whenever it is 0, the cyclic shifts of the string will indeed intersect at atmost one place.
in the case above the polynomial we get (when doing computations in this field GF(8)) is
x^4 + (g^2 + g + 1)*x^2 + (g^2 + g)*x 

Which indeed has 0 as the coefficient of x^3
You can try it yourself here:
just plug in the powers you want when evaluating poly, and then press evaluate.
This corresponds to the fact that subspaces have an intersection size that is a power of 2 over GF(2)and polynomials whose roots are a subspace over GF(2) will only contain powers that are powers of 2.

Monday, December 16, 2013

It's so exciting how Veganism is getting into the mainstream in Israel.
Domino's Pizza are now selling a vegan Pizza..
too bad I missed it by becoming a more fanatic gluten-free vegan.

What if before we were born God told us..
`I am going to given you exactly the experiences you need.. so that you can,
in the shortest time possible, reach a state of happiness and love.'

What if we knew this? How differently we would face each challenge.

I am happy when I feel each experience is a learning towards the union with you
that I dream about.

Sunday, December 15, 2013

Something I find it hard to relate to is how people can claim
to do something they are not able to do.
You have these Java libraries
XStream and JSON-io where their websites claim they are able to save any Java object to a file,
doesn't matter how complicated it is, or whether it is serializable.
But it's not true.. and surely they noticed it if I and other people have run into examples where it doesn't
the first time we try.
Their claims make you spend hours trying to make their libraries work.. when you could  have written the program you need yourself in an hour - which is what you end up doing of course..

Saturday, December 14, 2013

I was shocked to discover today that there is no generic way to save an object to a file in Java.
There is this thing called the Serializable interface, but it doesn't work well with complex objects -
like parameterized objects where the parameters are complex objects themselves.
My example: An instantiation of DirectedSparseGraph < Vertex, Edge >

Anyway.. while programming today, and thinking about search problems,
I was thinking how the universe from particles to atoms to molecules to brains
is now evolving, through the internet and search algorithms, to one big brain
where the individual neurons themselves are complex and self-aware -
knowing they are in this brain and able to change the way they connect to other neurons
when there is need.

And how this brain is evolving to be used to solve a new level of mathematical problems,
or explore the next level of musical compositions.

I am also thinking now that quinoa seeds are wusses.
If you put them in a pan of hot water with over things - like lentils or oats,
they will not take any of the water until the other things are done using it.

Two things I have discovered from trying to be gluten-free.

For the first time I have a consistent way to get the belly I have had for more than 20 years down.
Trying to not eat late, or too much, or fatty things never worked for me (partly cause I couldn't do it consistently). But now since I don't eat pastries and bread and pitas it's going down automatically.

Second - a great way to make wraps or sort of sandwiches - use this thing called rice paper.

Did I invent you?
Are you just my imagination?
It's been so long since we met in reality. By now I am like a religious fanatic, believing I am preparing for the day we meet again with no proof that it will come.. perhaps even with some evidence that it won't.

But that belief gives me an extra push of willpower throughout many small junctions during each day.

I come to the office. My instinct is to spend another 20 minutes browsing the web before starting to work.
I feel at first there is no chance I have the energy to avoid that temptation.
But then, sometimes, I think to myself: How will the decision I make at this moment affect how well things go between us if and when we meet in who knows how many years.
Amazingly to me, I find that if I feel making the harder decision will help things go better by 0.1% with a 0.1% probability, I can make the hard choice not only without effort, but with enthusiasm thinking about it as yet another small brick being placed in the construction of this future I dream about.

Wednesday, December 11, 2013

So sweet, for every taste of you
I walk a hundred years in the desert.
Your shining eyes assure me, time is not lost,
this is the road you must take.
Each day, in the afternoon, every cell of my body wants to be
closer to you.

Tuesday, December 10, 2013

What do you do with people in your life that just always want more?
More of your attention, more of your energy.
Anytime you feed them, instead of being grateful they just want more,
they are looking for the next bite.
Even if they don't say anything, you feel it. You are stressed, you feel like you
need to protect what you have.
Is there any solution except shutting them out completely?
I thought today of this analogy: You are stressed out about a friend owing you a few dollars.
Then, you suddenly discover that you have 100,000$ in your bank account that you did not know about.
At that moment, these dollars that your friend owes you seem like not a big issue.
Then again you forget about this money in your account and you are annoyed at your friend and stressed again.
Similarly, I have this feeling of being stressed about not getting enough, or not getting what I deserve.
I now meditate  2 hours in the morning sometimes -  the deeper effect starts only after the first hour so it's a shame to stop there.  After that, at random moments in the day, I have this feeling of having 100,000$ dollars in some spiritual bank account - this feeling of abundance and joy that is deep and independent of external events. And at those moments, things not being as they should externally - not getting the attention you want from a girl, someone in your office that can't stop talking, your room being a mess - are still things that preferably should improved, but are not reasons not to be happy.

Sunday, December 08, 2013

Your brain tricks you,dozens times a day..
in the corridors full of professors and Phd students
you manage to label someone as the bully,
some people as the popular group that won't associate with you.

Someone makes a comment in a lecture
with a slightly condescending tone..
you find yourself  hearing `all that you have to offer is worthless'
you attack back : `well why don't you prove it if it's so easy'
For a few minutes you are on auto-pilot..
but then you wake up.. this audience is not your enemy..

In your dreams you kick them away without checking who
they are,
just assume everybody is a monster..
anything else takes too much brain power.

Unexpectedly you meet her,
you see the world has something completely new to offer,
if you are able, for a moment, just to wake up..

Saturday, December 07, 2013

Be strong for me,
transform for me,
so that we can unite at a higher level than before.

That has always been my plan.
You resent it's not as easy as you imagined.
But you know it's worth it.
You know you have no choice.
You know no one can love you like this.
Dirty and real, voices playing with the energy they were born into.
Finally finding someone that can give them wings.
Growing in the ground full of dirt and rocks,
and water, giving life to everything around them.
Giving this present of their love to all that surround the
I feel this  frustration inside me.
I wish I could scream and ignore all consequences.
But I am the one burdened with being the constant repetitious reminder:

Be strong for me.
Transform for me.
So that we can unite at a higher plane than before.

Finally, found a place I enjoy showing tourists in Jerusalem.
The old city itself has a kind of weird, maybe negative, vibe.
Gethsemane church just outside of it to the east,
where supposedly Jesus prayed just before being caught by the Romans,
has a very special spiritual feel.
Maybe indeed some special event similar to Buddha's enlightenment happened here,
and the vibrations are still influencing it; because the atmosphere is quite noticeably different
from the area around, even though the place itself is quite a noisy tourist hotspot now.

Spiritual wealth

You sit for an hour in the forest.. you walk a little.
 You tell your monk friends `I was thinking of sitting for another hour..but maybe I'll just go home'
 And one of them asks you their regular trick question : `so are you going to choose the way of folding, or choose the way of strong determination'
You meditate with them for another hour.. you're not really sure how much time passed.
You start feeling the pain, together with the emotional pain..
 you feel clearly the correlation between the physical discomfort, the emotional discomfort, and your behavior patterns in critical situations.
 You feel how every extra minute, is worth its duration in gold.
 Every extra minute sitting with this discomfort, increasing the chances that in those critical moments, where a situation can lead into disaster or happiness, you will make the less wrong decision.
You drive from Haifa to Tel-Aviv. Feeling this wealth you have built up inside.
 Just watching the view, listening to the same CD.. how in the same situation just a day before you felt like a beggar.

Wednesday, December 04, 2013

I'm always wondering about whether stopping to drink coffee will make my alertness more stable throughout the day. Giving up coffee is quite a sad affair for me. I'm happy I found something else lately that has an even more positive affect on alertness and clarity - cutting off gluten - bread, pastries, ect. been doing it just for a few days and feel great.
Looks like it will take some time for my program to harmonize Giant Steps in Bach style..
and not sure that is the most interesting direction.

Here's something cute, meanwhile. It has the ability to stick a user chosen chord in the middle of a piece and go back to the original line in a relatively smooth way.

Original beginning of Chorale from BWV 1.6:

Sticking an Eb chord in the middle:

So happy I know how to embed Soundcloud files now :)

Monday, December 02, 2013

So much he wanted to know,
what was in her mind,
what she thought,
what she felt.

But he had only his imagination
to keep him company.
Imagining it was not just his imagination,
that he could read her thoughts,
that he knew what she thought and felt.
He didn't know what to do.
He wanted her so much in his life.
He said to himself, practice staying positive, practice being emotionally independent;
so that when you have the chance to be with her, you won't screw it up.
Her image became his motivation. Suddenly it became easy to stay calm in a
traffic jam, to spend 4 hours going in and out of the house looking for keys
and then looking for something else he dropped while looking for the keys.
What did it matter missing this or missing that?
All that mattered was using the time to develop the qualities that would enable them
to be together.
Suddenly difficult, frustrating situations were a good thing.
He knew she was difficult and frustrating, but not more than many other things.
He knew he was spoiled. He built a life where he could set the borders.
He could kick out anyone that did not act according to his predefined rules and behaviors.
He was good at not getting lonely.
But a life without this magic.. he was not ready for it,
he would always yearn for it.

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Hi! I am a computer science postdoc. For some reason google is not finding my new homepage so I added a link from this profile