How to use Loop without For or While
2 vues (au cours des 30 derniers jours)
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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
2 commentaires
James Tursa
le 29 Nov 2015
Modifié(e) : James Tursa
le 29 Nov 2015
Is this homework? What's wrong with using your loop?
Réponses (3)
Jan
le 29 Nov 2015
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]
4 commentaires
Jan
le 6 Déc 2015
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.
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