help in plotting variable from loop

Question

Arjun Paudel 2019-2-7

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/443814-help-in-plotting-variable-from-loop

评论： Arjun Paudel 2019-2-8

i am a beginner in matlab and was trying to plot a function needed for a exercise.

i am using a loop to calculate the value of the variable p1 for 10 times. the code calculates and displays the value but i also want to get the plot of p1 w.r.t number of iterations(i.e. i)

Thank you in advance for the help.

clc; clear all; close all; 
% pressure decrease rate
p1 = 1000000; % starting pressure in the tank 10 bars equivalent in pascals
V = 0.0055; % volume of the tank 5 liters in m^3 
M = 0.022897; % molar mass of air in kilograms
R = 8.3144598; %gas constant 
T = 298.15; % environment temperature 
m1 = 0;
v= 0.112e-3;
for i = 1:1:10
m = (M*V*p1)/(R*T);
m1 = (M*v*p1)/(R*T);
p1 = (R*T*(m-m1))/(V*M)
end
plot(i, p1)

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Answer 1

João 2019-2-7

0
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https://ww2.mathworks.cn/matlabcentral/answers/443814-help-in-plotting-variable-from-loop#answer_360062

在 MATLAB Online 中打开

Try this:

figure(1)
for i = 1:1:10
m = (M*V*p1)/(R*T);
m1 = (M*v*p1)/(R*T);
p1 = (R*T*(m-m1))/(V*M);
disp(['p1 = ' ,num2str(p1)])
plot(i, p1, 'ko')
hold on
end

Or this (instead of plotting during the loop, you can save the p1 values and then do the plot:

% preallocate p1
p1 = zeros();
for i = 1:1:10
m = (M*V*p1)/(R*T);
m1 = (M*v*p1)/(R*T);
p1(i) = (R*T*(m-m1))/(V*M);
disp(['p1 = ' ,num2str(p1)])
end
figure(1)
plot(i, p1, 'k')