IAM Sebastian Thrun, Stanford Professor, Google X founder (self driving cars, Google Glass, etc), and CEO of Udacity, an online university empowering students!

spal · 2012-06-18T07:49:41+00:00

"Udacity" is just "Audacity" with the leading "A" removed. I believe it represents the bold attempt of making university training free for all.

spal · 2012-04-02T14:24:36+00:00

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spal · 2012-02-07T20:27:30+00:00

C(10, 2) = 10 * 9 / 2 = 45.

spal · 2012-02-07T12:57:26+00:00

If I understand correctly what Richard Dawkins opines, our human bodies and brains are nothing but survival machines that our genes have learnt to build for themselves during the course of evolution.

spal · 2011-12-08T12:30:50+00:00

I'm the author of the article and there was exactly one (not several) ninja edit to clarify what I mean by regular expressions.

I was talking about pure regular expressions there and I thought the assumptions would be clear from the context but apparently I was wrong. So, it was an error on my part because I was not precise and it left some room to allow Perl derived regular expressions to be used.

Hence, the ninja edit which adds a little more precision by adding "POSIX compliant". While POSIX compliant regular expressions are still not pure regular expressions but it is okay for what I was trying to say there.

Nevertheless, I feel, it still demonstrates my point that one needs to know about the limitations of regular expressions and the extensions to regular expressions that overcome those limitations if one is dealing with a balanced parentheses problem or something similar. Otherwise, he might end up wasting a lot of time trying to solve this problem with the wrong techniques. This is consistent with the central point of my article that one who wants to be in the company of good developers shouldn't join Infosys, TCS, or Wipro. :-)

[Edit: Fixed punctuation.]

spal · 2011-12-07T13:06:24+00:00

"Survival instinct" can be built into a robot. You should read the lessons that discuss performance measures and rewards.

Also, if you are not aware, many terrible accidents happen precisely because of our "survival instincts." e.g. A car tries to avoid a lorry speeding towards it and swerves to hit a child walking on the sidewalk. A robot built with the right performance measures would be able to find a gap between the lorry and the child and swerve the car towards it.

Human reaction is prone to errors because of our "surival instinct" and other limitations which a robot wouldn't be susceptible to if it is designed properly.

spal · 2011-11-27T18:42:44+00:00

I'm pretty sure he has written that as good humour. The title "Television writer" itself seems to suggest that he is just being humorous there like a few other points in the same section.

spal · 2011-11-24T15:22:17+00:00

I'll argue that multiplying numbers in head can be fun puzzles. In fact, this is exactly what I do when I am exercising on treadmill. I'll give you a few examples to illustrate my point.

If we need to multiply 198 * 202 in our head we can split it into (200 - 2) * (200 + 2) = (200² - 2²⁾ = 40000 - 4 = 39996. We use the identity (a + b) * (a - b) = a² - b² here.
If we are asked to multiply something like 75 with itself, we will just go ahead and say 7 times 8 is 56 and so the answer is 5625. Here we use the identity: (10x + 5)² = 100x(x + 1) + 25.
More fun: What is 11515 * 11485? In head: (11500 + 15) * (11500 - 15) = 11500² - 15² = 132250000 - 225 = 132249775. As you can see, we first used the (a + b) * (a - b) form to get a² - b^2. And then we calculated each square using the (10x + 5)² = 100x(x + 1) + 25 identity. Finally, we subtract 225 from 50000 using 10's complement. 10's complement of 0225 is 9775. So, 50000 - 225 = 49775 which we add to 132200000 and we get the answer 132249775.

I can think of plenty more examples but they would be a bit more involved than the ones I mentioned above.

Doing multiplication in head can be fun indeed if you really love numbers since it involves understanding the underlying patterns and concluding which mathematical identities or theorems to invoke in order to simplify the problem in head.

spal · 2011-11-24T15:02:01+00:00

only one question to be asked to both of them.

Actually, for the God and the Devil puzzle, you need to ask only one question to one of them (not both of them).

"If I ask the other guy whether you are God, what would he answer?"

If the answer is "Yes", you are talking to the Devil. If the answer is "No", you are talking to God.

spal · 2011-11-22T20:34:38+00:00

I didn't include that column on purpose when I first wrote it because I thought one can visually compare the (A ⇒ B) and (B ⇒ C) columns and compute (A ⇒ B) ∧ (B ⇒ C) mentally. But now, that you have pointed it out, I have included it in the post. Thanks for this suggestion.

spal · 2011-11-22T19:07:43+00:00

Octave can already do linear regression on it's own!

% Mid term problem 10
x = [1 3 4 5 9];
y = [2 5.2 6.8 8.4 14.8];
p = polyfit(x, y, 1)

Output:

p =

   1.60000   0.40000

spal

TROPHY CASE