不使用findpeaks识别微分方程数值解数组峰值并生成比特序列

Got it, let's fix up your function to correctly identify local peaks and encode them into bits without using findpeaks. Here's a complete, working version along with breakdowns of how it works:

function Suite_bits = message_digital(V)
    % Initialize the output array to store encoded bits
    Suite_bits = [];
    % Get the number of elements in V
    num_elements = numel(V);
    
    % Loop through elements (skip first and last, since they can't be peaks)
    for i = 2:num_elements-1
        % Check if current element is a local peak (strictly greater than both neighbors)
        if V(i) > V(i-1) && V(i) > V(i+1)
            % Encode positive peak as 1, negative as 0
            if V(i) > 0
                Suite_bits = [Suite_bits, 1];
            else
                Suite_bits = [Suite_bits, 0];
            end
        end
    end
end

• Initialization: We start with an empty array Suite_bits to collect our encoded bits as we find peaks.
• Loop Boundaries: We skip the first and last elements of V because a local peak needs to have both a left and right neighbor to compare against—those edge elements can't satisfy that condition.
• Peak Detection: For each element in the middle of the array, we check if it's strictly greater than both its previous and next element. This is the standard definition of a local peak.
• Bit Encoding: Once we confirm a peak, we check its sign: positive peaks get a 1, negative peaks get a 0, which we append to our output array.

If your array V is large, dynamic resizing of Suite_bits (using [Suite_bits, bit]) can slow things down. A more efficient version preallocates space for the output first:

function Suite_bits = message_digital(V)
    num_elements = numel(V);
    peak_count = 0;
    
    % First pass: count how many peaks exist
    for i = 2:num_elements-1
        if V(i) > V(i-1) && V(i) > V(i+1)
            peak_count = peak_count + 1;
        end
    end
    
    % Preallocate output array
    Suite_bits = zeros(1, peak_count);
    idx = 1;
    
    % Second pass: encode peaks into bits
    for i = 2:num_elements-1
        if V(i) > V(i-1) && V(i) > V(i+1)
            % Use logical comparison to directly get 1/0 (cleaner syntax)
            Suite_bits(idx) = (V(i) > 0);
            idx = idx + 1;
        end
    end
end

This version runs faster for large datasets because it avoids repeatedly resizing the output array, which is a common MATLAB performance pitfall.

内容的提问来源于stack exchange，提问作者Desperados