Create one vector from several iterations in for loop

Hello, I am trying to split a vector into more pieces using a for loop. I have a vector, Lat, which contains latitude points. I wish to add more points in a linear fashion between the existing points in my Lat vector.

In order to do this, I am trying to use a for loop and the linspace operator as follows, splitting each interval in five new pieces.

 for i = 1:length(Lat)-1
    latitude(i) = linspace(Lat(i),Lat(i+1),5);
end

This does not work. How do I make the for loop understand that I wish to obtain a new vector containing all the points created using the linspace operator?

Answer 1

[Star Strider]

Try this:

for i = 1:length(Lat)-1
    latitude(i,:) = linspace(Lat(i),Lat(i+1),5);
end
latitude = reshape(latitude', 1, []);

[Anna]

Using this code I get the following error: Assignment has more non-singleton rhs dimensions than non-singleton subscripts.

Any idea how to fix this?

[Star Strider]

This works correctly for me:

Lat = 1:5;
for i = 1:length(Lat)-1
    latitude(i,:) = linspace(Lat(i),Lat(i+1),5);
end
latitude = unique(reshape(latitude', 1, []))

latitude =
  Columns 1 through 7
            1         1.25          1.5         1.75            2         2.25          2.5
  Columns 8 through 14
         2.75            3         3.25          3.5         3.75            4         4.25
  Columns 15 through 17
          4.5         4.75            5

I added the unique call because the original code created duplicates of the start and end values in each iteration.

[Anna]

Thank you for your help! This works.

I am also trying to make the number here specified as 5 vary for each iteration based on how large the interval between the points in the Lat vector is. I have made a vector "splitperint" with i-1 values. However the following code does not work:

 for i = 1:length(Lat)-1
    latitude(i,:) = linspace(Lat(i),Lat(i+1),splitperint(i));
end
latitude = unique(reshape(latitude', 1, []));

Do you have any input on how I can make this work? Or is this simply not possible with the linspace operator?

[Star Strider]

That won’t work because the columns aren’t equal. A cell array will allow unequal-sized vectors.

I simulated your changed code using a cell array as:

Lat = 1:5;
for i = 1:length(Lat)-1
    latitude{i} = linspace(Lat(i),Lat(i+1),5+i);
end
latitude = cell2mat(latitude);
latitude = unique(reshape(latitude', 1, []))

This works. Note the curly braces ‘{}’ indicating cell array addressing.

[Anna]

This works great! Thank you so much for you help!

[Star Strider]

As always, my pleasure!

Answer 2

[Andrei Bobrov]

 n = 5;
 Latitude = [Lat(1);reshape(reshape(Lat(1:end-1),1,[])...
                                        + cumsum(ones(n,1)* diff(Lat(:)')/n),[],1)];