How may I use reshape for this code?

count=0;
for j = 1:frame_number

    for i=1:15
        if (A(i,j)*A(i+1,j))<0
            count=count+1;
        end
           b(j)=count;
    end
    count=0;
end

[Dyuman Joshi]

What are you trying to reshape?

[Onur Batin Genc]

clc;
clear;
close all;
[x,fs]=audioread('susanhates8khz8bit.wav');
N = length(x);
frame_length=16;
time = 0:1/fs:N/fs-1/fs;

%nth frame ==>time
n=input("enter a number: ");
nth_frame_start=frame_length*(n-1)*(1/fs);
nth_frame_finish=frame_length*n*(1/fs);
A = [nth_frame_start,nth_frame_finish];
disp(A)

figure
subplot(2,1,1), stem(x), grid on, xlabel('sample'),axis tight;
subplot(2,1,2), plot(time,x),grid on, xlabel('time'),axis tight;

%ADD NOISE 
figure
Noise_Data = x + 0.01*randn(size(x));
title('Audio with noise'),plot(time,Noise_Data), grid on, xlabel('time'),axis tight;




%framing with for loop

frame_number=floor(N/frame_length); %frame_number = Length of the signal/frame_length
k=1;
    for i=1:frame_number
        for j=1:frame_length
            A(j,i)=x(k);
            k = k+1;
        end
    end
 %or without for loop A=reshape(x(1:frame_length*frame_number),frame_lengthe,frame_number);
count=0;
for j = 1:frame_number

    for i=1:15
        if (A(i,j)*A(i+1,j))<0
            count=count+1;
        end
           b(j)=count;
    end
    count=0;
end


    

[Onur Batin Genc]

Thats the main code of my approach. I was trying to use reshape instead of for loop to get zero crossing points.

Answer 1

[Jan]

Your loop method overwrites b(j) repeatedly. Setting count to 0 in two lines is confusing. Simpler:

for j = 1:frame_number
   count=0;
   for i = 1:15
       if (A(i,j) * A(i+1,j)) < 0
          count = count + 1;
       end
   end
   b(j) = count;
end

In a next step of simplification you can omit the if branch and add the result of the condition directly:

for j = 1:frame_number
   count=0;
   for i = 1:15
       count = count + ((A(i,j) * A(i+1,j)) < 0);
   end
   b(j) = count;
end

If the condition is true, its value is converted to 1. false is converted to 0.

But you can omit the loop completely:

AA = A(1:15, :) .* A(2:16, :);
b  = sum(AA < 0, 1);

There is no need for a reshape command.