How to add one scatter plor to another?

Hello,

I have two pairs of (x,y) arrays, say (x1,y1) and (x2, y2), they have equal length, but may be unordered. Also x1 set intersect x2. For example x1 = [0, 2, 4, 8, 1, 10] and x2 = [2, 9, 11, 13, 5, 7], corresponds to y1 = x1.^4 and y2 = sqrt(x2).

How to scatterplot y1+y2 sum on union of x1 and x2? Thanks.

Answer 1

[Azzi Abdelmalek]

x=[x1 x2]
y=[y1 y2]
[val,idx]=sort(x);
new_x=val
new_y=y(idx)
plot(new_x,new_y)

[Vasily Kozhevnikov]

x = [x1 x2] isn't union, and the last command will not plot sum

[Azzi Abdelmalek]

It's not clear, maybe this:

x=sort(unique([x1 x2]))
y1=x.^4;
y2=sqrt(x)
plot(x,y1+y2)

Answer 2

[Azzi Abdelmalek]

%or you are looking for

x1 = [0, 2, 4, 8, 1, 10]
x2 = [2, 9, 11, 13, 5, 7],
y1=x1.^4;
idx1=find(ismember(x1,x2))       % find common values in x1 & x2
y1(idx1)=y(idx1)+sqrt(x1(idx1))   %add second function to common values
x2(ismember(x2,x1))=[]           % remove common value from x2
y2=sqrt(x2)
[x,idx]=sort([x1 x2])
y=[y1 y2]
y=y(idx)
plot(x,y)

Answer 3

[Vasily Kozhevnikov]

Sorry, but in my task y1 is a list of values, but not an analytic function of x1. But now to my opinion I have a solution

x = union(x1, x2); f = interp1(x1, y1, x, 'cubic', 0) + interp1(x2, y2, x, 'cubic', 0); plot(x, f)

it may works

[Azzi Abdelmalek]

Vasily, in your question y1 and y2 are not a list of object, but functions of x1 and x2.