Drawing a line through the peak of the plot

I have a plot as follows. How can I add vertical lines through the peak points (total 3 lines here) in the plot ?

Code:

I have written the code as:

"clear all;

m = 4.48e-26; % mass of Nitrogen molecule

k = 1.38e-23; % Boltzmann Constant

p = 0:2800;

ind = 1;

for T = 300:500:1500;

% constant computation

c1 = 4*pi*(m/(2*pi*k*T))^(3/2);

c2 = m/(2*k*T);

c3 = 3*m*k*T;

u(ind,:) = c1*(p.^2.*exp(-(c2*p.^2)));

%u2(ind,:) = c1*c3*exp(-(3/2))

ind = ind+1;

end

figure(1)

plot(p,u)

xlabel('P')

ylabel('probability')

"

[Walter Roberson]

xline()

Answer 1

[Paul]

m = 4.48e-26; % mass of Nitrogen molecule
k = 1.38e-23; % Boltzmann Constant
p = 0:2800;
ind = 1;
for T = 300:500:1500;
    % constant computation
    c1 = 4*pi*(m/(2*pi*k*T))^(3/2);
    c2 = m/(2*k*T);
    c3 = 3*m*k*T;
    u(ind,:) = c1*(p.^2.*exp(-(c2*p.^2))); 
    %u2(ind,:) = c1*c3*exp(-(3/2))
    ind = ind+1;  
end
figure(1)
plot(p,u)
xlabel('P')
ylabel('probability')

Find the maximum points and their corresponding indices

[maxu,index] = max(u,[],2);

Plot vertical lines at p for each index. Use the options for xline to customize color, etc.

xline(p(index(1)));
xline(p(index(2)));
xline(p(index(3)));

[Ismita]

Thank you so much!

Could you please explain the line

"[maxu,index] = max(u,[],2);" specially max(u,[],2) meaning. I am a new user of Matlab. Thanks again.

[Paul]

Check out the doc page for max. Freel free to come back if you still have questions.