Find which command used

What matlab command, or combination of commands (using 25 characters or less), could be used to create the following matrix?

1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0

1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0

1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0

1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0

1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0

1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0

1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0

1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0

1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0

1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0

1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0

1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0

1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0

1 1 0 0 0 1 1 0 0 0 1 1 0 0 0 1 1 0 0 0

1 1 1 0 0 1 1 1 0 0 1 1 1 0 0 1 1 1 0 0

1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Hint: Look for a lower triangluar matrix that is repeated many times. First try to produce that lower triangular matrix with as few characters as possible.

[Guillaume]

The "or less" is a bit misleading (or a challenge?) as the straightforward way is exactly 25 characters if you forfeit any kind of whitespaces.

Don't expect people to do your homework for you, since that's cheating.

[Adam]

This isn't a challenge forum. That is what Cody is for. And as Guillaume says, obviously it isn't a "please do my homework for me" forum either.

[Jan]

Some forum users do like challenge questions.

I thought about urlread of this page and a tiny-url. With kron I got 29 characters. What might be the shortest dec2bin approach? When using repmat is allowed, are user-defined M-files "Matlab commands" also? Then 1 character is sufficient already. What about drawing an image and using getframe - would the image belong to the limited number of characters or is this not part of the "command"? In fact, you can learn a lot about Matlab by this question.

[Star Strider]

I don’t like challenge questions in MATLAB Answers. As Adam correctly pointed out, that is what Cody is for.

I assume the Questions posted on Answers are genuine requests for help. While some homework help Questions may not be appropriate (in my opinion, they amount to cheating), the vast majority of Questions here are appropriate.

If you already know the best solution, why ask for help?

If you’re posing a challenge, go to Cody.

[Guillaume]

The way this question is formulated, it really looks like an assignment question. That's why your answer is appropriate, it gives the OP a way to find the solution while not giving it away.

[Star Strider]

Thank you. That was my original impression, making the OP’s Comment to my Answer somewhat puzzling to me. What does ‘sorry, not’ mean?

[Jan]

I miss Matt Figs the hump-day puzzlers. The assessment method of Cody collide with my personal opinion about nice and efficient code.

[Adam]

Yes, I never go near Cody personally since I found that 'best' solutions to many problems involve some ridiculous use of regexp. Personally my idea of good code doesn't involve using the fewest characters possible!

Answer 1

[Star Strider]

This looks like a homework assignment, so I’ll direct you to three functions: ones, tril, and repmat.

[you wu]

sorry,not

[Star Strider]

I’m lost. What do you mean?