How to use Loop without For or While

Hello everyone Consider this code:

n=10;
m=5;
A=zeros(n,m);
A(1,:)=[1];
for i=1:n-1
    A(i+1,:)=3*A(i,:)
end

answer is :

A =

             1           1           1           1           1
             3           3           3           3           3
             9           9           9           9           9
            27          27          27          27          27
            81          81          81          81          81
           243         243         243         243         243
           729         729         729         729         729
          2187        2187        2187        2187        2187
          6561        6561        6561        6561        6561
         19683       19683       19683       19683       19683

How can I calculate the A without using For (or while) , like this code:

n=10;
m=5;
A=zeros(n,m);
A(1,:)=[1];
A(2:end,:)=3*A(1:end-1,:)

unfortunately this code appears this:

A =
     1     1     1     1     1
     3     3     3     3     3
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0

Thanks every one

[James Tursa]

Is this homework? What's wrong with using your loop?

[Ardalan Norouzi]

yes it's question of my teacher for homework please help me

Answer 1

[Walter Roberson]

See bsxfun

[Ardalan Norouzi]

Could you please write every lines of the code for me? I'm new in Matlab Thanks

[Jan]

@Ardalan Norouzi: It is your homework. If the complete solution is posted in the forum, you have to cheat when you submit it. you can find the solution by your own, when you read the documentation of bsxfun.

[Ardalan Norouzi]

I'm trying to write the code but I can't complete it, Please help me

Answer 2

[Jan]

2 hints:

3 .^ (0:9)
% [1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683]

[1;2;3] * [4,5,6]
% [4, 5, 6;
%  8, 10, 12;
%  12, 15, 18]

[Ardalan Norouzi]

thanks but not in this way

[Jan]

I do not understand your comment. You can combine the two lines to obtain the wanted result. You can also use repmat to create the matrix.

[Ardalan Norouzi]

I would like to create an array of elements which created with their last elements. for example A is an array with 1 row and 5 column , first column is 1 and second column is 3*A(first) and third column is 3*A(second) and ... The whole of this procedure without using "For" or "While"

[Jan]

So what's wrong with the hints I gave?! I hesitate to post the complete solution, because otherwise you cannot submit this as a your homework without cheating. But the shown methods allow to solve the problem easily. If you do not only claim, that they do not help you but post, what you have tried and why you think, that this does not help, I had a chance to give further hints.

3 .^ (0:9).'

Now this must by multiplied by a vectors of ones to obtain the shown matrix.

Answer 3

[Ardalan Norouzi]

Please somebody help me , I need this code , you're my last chance.

[Jan]

See my comment.