Looping through 3D matrix

5 次查看（过去 30 天）
Sophia
Sophia 2011-11-21
Hi, I'm trying to populate a 3D matrix of zeros (3x14x12), nextvoy with a subset of rows in another matrix, trade, according to a lookup table, desigcty. The matrices look like this: trade =
682
682
682
566
566
566
579
579
579
desigcty =
682
579
566
>> tmp_x
tmp_x =
1
1
1
2
2
2
3
3
3
4
4
4
For example, nextvoy(:,:,1) should have all the entries of 682, then nextvoy(:,:,2) has 579, and then 566 for nextvoy(:,:,3). Then it should repeat this for the next 3 i's in nextvoy and so on.
The code I have overwrites each array in nextvoy with 566 because it's the last j (it's not performing according to expectations):
for i = 1:(size(desigcty,1)*nx); %for all load ports and ships: (:,:,i)
for j = 1:size(desigcty,1); %loop through each load port (j,:,:)- 3 for now
nextvoy(:,1,i)= tmp_x(i,1); %ship ID
[r1,~,~]= find(trade(:,1)==desigcty(j,1),1, 'first');
[r2,~,~]= find(trade(:,1)==desigcty(j,1),1, 'last');
nextvoy(:,2:9,i)= trade(r1:r2,1:8); %copies subset of trade matrix according to load code
end;
end;
For example, part of the sequence this code produces is >> nextvoy(:,1:2,1:6)
ans(:,:,1) =
1 566
1 566
1 566
ans(:,:,2) =
1 566
1 566
1 566
ans(:,:,3) =
1 566
1 566
1 566
ans(:,:,4) =
2 566
2 566
2 566
ans(:,:,5) =
2 566
2 566
2 566
ans(:,:,6) =
2 566
2 566
2 566
But I need: >> nextvoy(:,1:2,1:3)
ans(:,:,1) =
1 682
1 682
1 682
ans(:,:,2) =
1 579
1 579
1 579
ans(:,:,3) =
1 566
1 566
1 566
ans(:,:,4) =
2 682
2 682
2 682
ans(:,:,5) =
2 579
2 579
2 579
ans(:,:,6) =
2 566
2 566
2 566
And so on...
  3 个评论
显示 1更早的评论
Jan
Jan 2011-11-21
@Sophia: again, please format the code in your original message. You only have to press the "edit" button, mark the text with the mouse and press the "{} code" button. It is really worth to spend the necessary 4 seconds to make it easier for the readers.
I still do not get the point iof the question. Does the code do what you want? Do you get an error message? Does the result differ from your expectations - if so, how?
It would be much easier to answer, if you post running code. Currently I cannot copy&paster the definitions of trade and desigcty. But I want to concentrate on producing an answer, not on finding out, what the question could be.
Sophia
Sophia 2011-11-21
Does that help? Solution doesn't have to be in order of desigcty.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Andrei Bobrov
Andrei Bobrov 2011-11-21
in your case
a1 = sortrows(tride);
nextvoy = permute(reshape(a1,3,3,[]),[1 3 2]);
variant 2
a1 = sortrows(tride);
a2 = sort(desigcty(:,1));
[b,n] = histc(a1(:,1),a2);
nextvoy = zeros(max(b),14,numel(b));
m = size(tride,2);
for i1 = 1:numel(b)
nextvoy(1:b(i1),1:m,i1) = a1(n==i1,:);
end
EDIT variant
[c,idx] = sort(desigcty(:,1));
[b,n] = histc(tride(:,1),c);
nextvoy = [permute(ones(max(b),1)*tmp_x(:)',[1 3 2]),zeros(max(b),13,numel(tmp_x))];
k = size(tride,2);
p0 = numel(unique(tmp_x));
p = numel(tmp_x)/p0;
for i1 = 1:numel(b)
i2 = idx(i1);
nextvoy(1:b(i2),2:k+1,i1:p:end) = repmat(tride(i2==n,:),[1,1,p0]);
end
  2 个评论
Sophia
Sophia 2011-11-21
Thanks, but that's not exactly what I'm looking for. The point of having it search for first and last occurrence of codes is to allow for flexibility since there may be more than 3 occurrences in later iterations. Also, I need it to populate a 3D matrix size = 3 14 12 4 times (3 of same subset, 4 times). Thanks for the help.
Sophia
Sophia 2011-11-21
Brilliant, that worked, thank you very much!

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Logical 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by