I need help preallocating array?

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ME
ME on 12 Apr 2015
Edited: pfb on 12 Apr 2015
I need help making this array preallocated.
p = 10;
newArray = [];
array = [];
for i = 1:p
a= variable1;
b = variable2;
c = variable3;
d = variable4;
e = variable5;
array = [a,b,c,d,e]
newArray= [newArray array];
end

Accepted Answer

pfb
pfb on 12 Apr 2015
Look at the function "zeros".
array = zeros(1,5);
newArray = zeros(1,5*p);
and, in the loop
newArray((1+(i-1)*5):(i*5))=array;
This way all you need is allocated before the loop.
I assume that the assignments of a through e come from function that have a different value for different i's.
If they are the same, it's just a tiling problem. You need "repmat".
  5 Comments
pfb
pfb on 12 Apr 2015
not really in a new row.
In your code "array" is copied at the end of the row vector newArray. No new rows.
Use the semicolon operator to add new rows. You should have written
myArray = [myArray; array];
I think you should read some documentation.
Anyway, to allocate your matrix (not vector)
newArray = zeros(p,5);
Filling it, now is much simpler. This fills the ith row of newArray with the current values in array.
newArray(i,:) = array;
You should state your problem better. Apparently, what you needed was filling the rows of a matrix, all the time.
And perhaps take a look into the basics of matlab.

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