# Aligning then subtracting unequal length column vectors

1 view (last 30 days)
Jason on 25 Apr 2024
Commented: Voss on 25 Apr 2024
Hello, i have 2 vectors xspots and xgrid
xspots = [
2600.00
2679.00
2802.00
2924.00
3046.00
3169.00
3291.00
3413.00
3536.00
3658.00
3781.00];
xgrid = [
2680.00
2803.00
2926.00
3049.00
3172.00
3294.00
3417.00
3539.00];
Crucially they are not the ame length
what I want to do is locate in both, the nearest value to a reference (called ref) i.e. ref=3200.
I then want to align these two vectors such that the values closest to ref lign up (i.e. this will then be the values 3169 & 3172.)
Then I want the diff between xspots and xgrid in this aligned state.
This was my attempt, but its in 2 parts.
ref=3200;
n=min(numel(xspots,xgrid));
data=[];
for i=1:n
data(i,1)=xspots(i);
data(i,2)=xgrid(i);
end
data(:,3)=data(:,1)-data(:,2)
%% and then repeat this for > ref.... but it seems long winded.
Jason on 25 Apr 2024
Moved: Dyuman Joshi on 25 Apr 2024
This is the output I need. Notice how I align the two vectors at the ref. value, and then where there is overlap perform the subtraction
Jason on 25 Apr 2024
Moved: Dyuman Joshi on 25 Apr 2024
I forgot to say, i need the 1st column values together with tge 3rd column (as i will be plotting these)

Voss on 25 Apr 2024
Edited: Voss on 25 Apr 2024
xspots = [
2600.00
2679.00
2802.00
2924.00
3046.00
3169.00
3291.00
3413.00
3536.00
3658.00
3781.00];
xgrid = [
2680.00
2803.00
2926.00
3049.00
3172.00
3294.00
3417.00
3539.00];
ref=3200;
[~,idx1] = min(abs(xspots-ref));
[~,idx2] = min(abs(xgrid-ref));
n1 = numel(xspots);
n2 = numel(xgrid);
ii = intersect((1:n1)-idx1,(1:n2)-idx2);
difference = xspots(idx1+ii)-xgrid(idx2+ii)
difference = 8x1
-1 -1 -2 -3 -3 -3 -4 -3
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>
result = [xspots(idx1+ii) difference]
result = 8x2
2679 -1 2802 -1 2924 -2 3046 -3 3169 -3 3291 -3 3413 -4 3536 -3
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>
Jason on 25 Apr 2024
thankyou thats perfect!
Voss on 25 Apr 2024
You're welcome!

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