Stacking data sets into 1

I am trying to stack data. I have an matrix (ROI), that I obtain the rows from. Each row is my y data. The x data is just the column number (1:num_of_columns)

for each row of data, I need to take the column number and shift it by an amount in a vector called thresh (and column2).

I then want to combine each set of data. The left graph shows the first 2 rows i plot seperately before the x-axis shift. The right hand graph is individual plots of all the rows each shifted (from the vector thresh(:,2)).

stack=[];
for i=1:num_of_rows
    y=ROI(i,:);
    plot(x-thresh(i,2),y,'r.'); hold on; 
    if i==1
      stack(:,1)=x-thresh(i,2);
      stack(:,2)=y;
    else
       stack(:,1)=vertcat(stack(:,1),x-thresh(i,2))
       stack(:,2)=vertcat(stack(:,2),y)
    end    

end    
grid on;
stack

Error using vertcat
Dimensions of matrices being concatenated are not consistent.

Error in ArchimedesIQC>pushbutton126_Callback (line 12236)
       stack(:,1)=vertcat(stack(:,1),x-thresh(i,2))

[Star Strider]

What are the row and column sizes of ‘x’ and ‘y’?

Since ‘thresh’ appears to be a scalar in each iteration, it is likely not the problem.

[Guillaume]

No, the problem is

x(:, 1) = [x(:,1), something_not_empty]

the number of elements on the left hand side is always going to be smaller than the number of elements on the right hand side. This is always going to result in an error in matlab.

The error itself may be caused by x being a row vector instead of a column vector.

[Star Strider]

‘The error itself may be caused by x being a row vector instead of a column vector.’

Precisely the reason I asked for their dimensions before proceeding!

Answer 1

[Guillaume]

I have not really understood what it is you're trying to achieve but fixing your error is easy:

else
   stack = [stack; x-thresh(i, 2), y];  %or vertcat(stack, [x-thresh(i, 2), y]);
end

Note that this assumes that x and y are column vectors. If they are row vectors, you need to transpose them:

stack = [stack; x.' - thresh(i, 2), y.'];