Undefined function 'findpeak' for input arguments of type 'double'. Error in untitled4 (line 40) [peaks, t] = findpeak(pred);

clc;
clear;
close all;
% Parameters
a = 1;            % Attack rate
h = 0.5;          % Handling time
b = 0.5;          % Conversion efficiency
d = 0.4;          % Predator death rate
epsilon = 0.01;   % Timescale separation
K = 5;            % Carrying capacity
r_values = linspace(0.1, 1, 200);  
x0 = 1.0;
y0 = 0.5;
initCond = [x0; y0];
dt = 0.01;
tspan = 0:dt:5000;
tr = 6000/dt;  % time to discard as transient
results = [];
rosenzweigMacArthur = @(t, Y, r) [
    r * Y(1) * (1 - Y(1)/K) - (a * Y(1) * Y(2)) / (1 + h * Y(1));  
    epsilon * ((b * a * Y(1) * Y(2)) / (1 + h * Y(1)) - d * Y(2))  
    ];
for i = 1:length(r_values)
    r = r_values(i);
    opts = odeset('AbsTol',1e-12,'RelTol',1e-10);
    [t, Y] = ode45(@(t,Y) rosenzweigMacArthur(t,Y,r), tspan, initCond, opts);
    pred = Y(tr:end, 2);   % discard transient
    
    
    [peaks, t] = findpeak(pred);
    if isempty(peaks)
        % no oscillation detected → steady state
        results(end+1, :) = [r, pred(end)];
    else
        % oscillatory: store unique peaks
        up = unique(round(peaks,5));
        for k = 1:length(up)
            results(end+1, :) = [r, up(k)];
        end
    end
end
% Plotting bifurcation diagram
figure('Color','w');
plot(results(:,1), results(:,2), 'k.', 'MarkerSize', 6);
xlabel('Prey Growth Rate (r)', 'FontSize', 12);
ylabel('Predator Population Peaks or Fixed Points', 'FontSize', 12);
title(sprintf('Bifurcation Diagram using findpeaks (K = %.1f)', K), ...
    'FontWeight','bold','FontSize',13);
grid on;
% Save figure
saveas(gcf, 'bifurcation_diagram_peaks.png');

Answer 1

[Mathieu NOE]

it's findpeaks with an "s" at the end (missing in your code)

findpeaks - Find local maxima - MATLAB