Dynamic window forming in efficient way in MATLAB

Question

Can someone help me to provide an efficient way or help me to perform the provide code to do make same results in minimal possible steps. I shall be grateful to you.

I have an Original Array:

A = [1 1 1 4.3 4.5 4 4.3 3 1 0 0 2 6.2 6.3 6 6.2 7.4 8 7.2 2 2 3 3 2];

Output Looks like:

A = [1 1 1 4 4 4 4 3 1 0 0 2 6 6 6 6 6 7 7 2 2 3 3 2];

I apply some restrictions and removed some values from array of local maxima’s after that I received some new arrays.

Yposlocfiltered = [6    15    23];
idx             = [4     6     3];
Yneglocfiltered = [2     9    20];
idx_neg         = [1     1     2];

Where I will find idx(local maxima value) I will check if values behind and ahead are greater make a window.

Example

If I will find 4 and 4.5, 4.3 is greater than 4 include it in backward window 
4.3 is greater than 4 include it in forward window.

I need to find range of values behind local maxima and ahead local maxima.

I have tried to write a code that’s works fine but issue is that it’s too long.

Can someone please provide me an idea to perform this action in minimal steps and in faster ways?

I have only provided code for positive local maxima’s as for negative local maxima code Is just replica of this.

Code:only for positive local maximas

 clc
 clear all

 A = [1 0 1 4.3 4.5 5 4.3 3 0 0 0 2 6.2 6.3 7 6.2 7.4 8  7.2 1 2 3 4 2];
 Yposlocfiltered = [ 6    15    23];
 idx = [4     6     3];
 Yneglocfiltered = [2     9    20];
 idx_neg = [1     1     2];

 for b = 1: numel(idx)
 for c = 1:numel(A)
 f = Yposlocfiltered(1,b)-c ;
 g = Yposlocfiltered(1,b)+c ;

 %   if (f > 0 && g <= numel(X))
 if(f > 0)   
 if  (A(Yposlocfiltered(1,b)-c))> idx(1,b)

 else 
   d= f+1;
   z(b)= d;
   backward_window = z;
  break
 end        

 end

 end 

 end 

 for r = 1: numel(idx)
 for s = 1:numel(A)
 u = Yposlocfiltered(1,r)-s ;
 v = Yposlocfiltered(1,r)+s ;

 %   if (f > 0 && g <= numel(X))
 if(v <=numel(A))   
 if  (A(Yposlocfiltered(1,r)+s))> idx(1,r)

 else 
   w= v-1;
   y(r)= w;
   forward_window = y;
 break
 end        

 end

 end 

end 

n=4
for i=1:length(backward_window)
range = backward_window(i): forward_window(i);
p = range 
if n <= numel(p)
        p = range(1:n)
         A( p) = idx(i);
else
%   if (size(range)<= 3)
A( p) = idx(i);
end 
end

Answer 1

From the first look at your code, I believe you can combine your first two for loops into one.

sA = numel(A);
sI = numel(idx);

for i = 1:sI
    f = Yposlocfiltered(i) - [1:sA];
    g = Yposlocfiltered(i) + [1:sA];
    f(f<1) = [];
    g(g>sA) = [];
    backward_window(i) = f(find(A(f) <= idx(i), 1)) + 1;
    forward_window(i) = g(find(A(g) <= idx(i), 1)) - 1;
end

Here, you can use find to locate the element of an array matching the specified condition, i.e. g <= numel(X) or A(f) <= idx(i).

Your last loop which modifies A can also be integrated into the same loop, so you can have:

sA = numel(A);
sI = numel(idx);

n=4;
for i = 1:sI
    f = Yposlocfiltered(i) - [1:sA];
    g = Yposlocfiltered(i) + [1:sA];
    f(f<1) = [];
    g(g>sA) = [];
    backward_window(i) = f(find(A(f) <= idx(i), 1)) + 1;
    forward_window(i) = g(find(A(g) <= idx(i), 1)) - 1;
    range = backward_window(i) : forward_window(i);
    if n <= numel(range)
        A(range(1:n)) = idx(i);
    else
        A(range) = idx(i);
    end
end