How to find the indices of a vector from another vector

I have two sets of array A and B in the attachment.

Dataset A is the cone of influence (COI) of the power of wavelet B. Which means they both have the same length. When I plot it looks like the graph below.

Please how can I find the position of A (COI) in the matrix B (contour) or how can I select the variables inside the COI?

Answer 1

[TTA]

This was the answer I expect.

power = (abs(wave)).^2 ;        % compute wavelet power spectrum
incoi=(period(:)*(1./coi)<1);
Powd1 = zeros(numel(power(:, 1)), numel(power(1, :)));
for k = 1:numel(power(1, :))
    for j = 1:numel(power(:, 1))
    pow1 = power(j, k);
    incoi1 = incoi(j, k);
        if incoi1 == 1
            Powd1(j,k) = pow1;
        else            
            Powd1(j,k) = nan;
        end   
    end
end

Answer 2

[Shubh Pareek]

Hi @TTA,

From what I have understood you want points from B which follow a certain condition with respect to points in A.

You can try this method -

%So suppose if your array A is 
A = [ 5 4 3 2 1 2 3 4 5 ]

A = 1×9

5 4 3 2 1 2 3 4 5

%and B is 
B = [  10 8 6 4 2 4 6 8 10 ; 4 3 2 1 0 1 2 3 4 ]

B = 2×9

10 8 6 4 2 4 6 8 10 4 3 2 1 0 1 2 3 4

%and time axis is 
time = [1 2 3 4 5 6 7 8 9]

time = 1×9

1 2 3 4 5 6 7 8 9

%now you plot your respective values 
plot(time,A)
hold on
plot(time,B)
xlabel("time")
%let the middle line be our COI, and you only want points in between then
%we create new array B_inside which only has points from B which are inside
%A
hold off

inside_points  = B-A > 0 %this will chose indices from B which follow this condition

inside_points = 2×9 logical array
   1   1   1   1   1   1   1   1   1
   0   0   0   0   0   0   0   0   0

B_inside = B.*inside_points %and then we make the indices that we don't want as 0

B_inside = 2×9

10 8 6 4 2 4 6 8 10 0 0 0 0 0 0 0 0 0

plot(time,A)
xlabel("time")
hold on 
plot(time,B_inside)

%now we have points that are only inside the middle curve 

I hope this helps with your quey .

Helpfull Resources -

Logical Arrays – Ernesto Salcedo, PhD (wordpress.com)

Boundary Effects and the Cone of Influence - MATLAB & Simulink - MathWorks India(MATLAB's documentation on COI )