Aligning then subtracting unequal length column vectors

Question

Jason 2024-4-25

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2111761-aligning-then-subtracting-unequal-length-column-vectors

评论： Voss 2024-4-25

Hello, i have 2 vectors xspots and xgrid

xspots = [
00
00
00
00
00
00
00
00
00
00
00];

xgrid = [
00
00
00
00
00
00
00
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;
           mask = xgrid(:,1) < ref;              
           xgrid(mask,:) = [];
           
           mask = xspots(:,1) < ref;
           xspots(mask,:) = [];
           
           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.
           
           
               
               
       

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Jason 2024-4-25

移动：Dyuman Joshi 2024-4-25

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 2024-4-25

移动：Dyuman Joshi 2024-4-25

I forgot to say, i need the 1st column values together with tge 3rd column (as i will be plotting these)

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Answer 1

Voss 2024-4-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2111761-aligning-then-subtracting-unequal-length-column-vectors#answer_1448051

编辑：Voss 2024-4-25

在 MATLAB Online 中打开

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>