# shift matrix to the right

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Nimasha Pilippange on 26 Feb 2022
Hello,
I need to compare 2 matrices. One is 1x1280 and other is 1x5120. So I need to take the 1st one to the other range. How do i do that.
for example: A=[0 0 1 1 0 0 1 1], B=[0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1]. The number of elements in B is an integer multiple of number of elements in A. After shifting I need to subtract A by B.
Any Idea?
Image Analyst on 27 Feb 2022
You forgot to answer my question. Which is it: 1 or 2?

Image Analyst on 27 Feb 2022
Try this:
markerSize = 30;
% Say a goes from 250 to 4800 and has 60 elements
a = 250 + (4800-250) * rand(1, 60);
% Say b goes from 100 to 900 and has 30 elements
b = 100 + (900-100) * rand(1, 30);
plot(a, 'b.-', 'LineWidth', 2, 'MarkerSize', markerSize);
hold on;
plot(b, 'c.-', 'LineWidth', 2, 'MarkerSize', markerSize);
grid on;
% Rescale b so that it also goes from 250 to 4800
b = rescale(b, min(a), max(a));
% Interpolate b so that it has the same number of elements as a.
bq = linspace(1, length(b), length(a));
b2 = interp1(b, bq);
plot(b2, 'r.-', 'LineWidth', 2, 'MarkerSize', markerSize);
% Find differences
c1 = a - b2;
c2 = b2 - a;
legend('a', 'b', 'b2') Nimasha Pilippange on 28 Feb 2022
I used this and it seems working. Thank you very much

Scott MacKenzie on 26 Feb 2022
Edited: Scott MacKenzie on 26 Feb 2022
Perhaps this is what you are looking for:
A=[0 0 1 1 0 0 1 1]
A = 1×8
0 0 1 1 0 0 1 1
B=[0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1]
B = 1×16
0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1
m = numel(A);
n = numel(B);
Anew(n-m+1:n) = A % shifted to match B with zeros at beginning
Anew = 1×16
0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 1

Image Analyst on 26 Feb 2022
It appears no one knows what you mean since it's not clearly explained and you didn't give the resulting difference vector. So here is another guess:
A=[0 0 1 1 0 0 1 1];
B=[0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1];
% Resize smaller vector to be the same size as the larger vector.
a2 = imresize(A, size(B), 'nearest')
% "subtract A by B" - whatever that means. Here are two possibilities
c = a2 - B
c = B - a2
Let me know if either of these is what you want.

Voss on 27 Feb 2022
Maybe use interp1() (or resample()):
nx = 20;
x = randn(1,nx);
% xr = resample(x,4,1);
xr = interp1(1:nx,x,1:0.25:nx);
figure();
plot(1:nx,x,'-o');
hold on
plot(0.25*(4:numel(xr)+3),xr,'.');
legend({'Original','Interpolated x4'}) 