Why my graph only get one line?

clear all

clc

clf

% Initial Value and time step

a = 0; % Lower limit of Integration from 21 Oct 2020

b = 700; % Upper limit of Integration at 20 Oct 2021

h = 0.5; % h = delta_x

n = ((b-a)/h); % no. of points

T = 70;

TT = 100;

tau0 = 2*10^-9;

tau1 = 1.41*10^-9;

alpha = 0.0005;

gamma1 = 1/10;%7.31;

gamma2 = 1/15;%0.11;

mu = 1/50;%1.26;

y10 = 8.18*10^7;

y20 = 5.0604*10^3;

y30 = 4.4876*10^3;

y40 = 4590;

y = zeros(n, 4);

x = zeros(n, 1);

y(1, :) = [y10; y20; y30; y40];

x(1) = a;

tau(1) = tau0;

fcn = @(x, y) [-tau(1) * y(1) * (y(2) + y(3)),...

alpha * tau(1) * y(1) * (y(2) + y(3)) - gamma1 * y(2),...

(1-alpha) * tau(1) * y(1) * (y(2) + y(3)) - ((gamma2 + mu) * y(3)),...

gamma1 * y(2) + gamma2 * y(3) ]; % system function

for i = 1:n-1

x( i + 1 ) = x(i) + h;

if (i >= 1) && (i < T);

tau(i) = tau0;

elseif (i >= T) && (i <= TT);

tau(i) = tau0*exp(-alpha*i);

else(i > TT);

tau(i) = tau1;

end

d1 = h * fcn(x(i), y(i, :));

d2 = h * fcn(x(i), y(i, :) + d1 / 2);

d3 = h * fcn(x(i), y(i, :) + d2 / 2);

d4 = h + fcn(x(i), y(i, :) + d3);

y(i+1, :) = y(i, :) + ((d1 + d2 + d3 + d4)* (h / 6));

end

figure(1)

plot(x,y(:,3),'blue')

hold on

%%%%%

clear all

clc

clf

% Initial Value and time step

a = 0; % Lower limit of Integration from 21 Oct 2020

b = 700; % Upper limit of Integration at 20 Oct 2021

h = 0.5; % h = delta_x

n = ((b-a)/h); % no. of points

T = 70;

TT = 100;

tau0 = 2*10^-9;

tau1 = 1.41*10^-9;

alpha = 0.01;

gamma1 = 1/10;

gamma2 = 1/15;

mu = 1/50;

y10 = 8.18*10^7;

y20 = 5.0604*10^3;

y30 = 4.4876*10^3;

y40 = 4590;

y = zeros(n, 4);

x = zeros(n, 1);

y(1, :) = [y10; y20; y30; y40];

x(1) = a;

tau(1) = tau0;

fcn = @(x, y) [-tau(1) * y(1) * (y(2) + y(3)),...

alpha * tau(1) * y(1) * (y(2) + y(3)) - gamma1 * y(2),...

((1-alpha) * tau(1) * y(1) * (y(2) + y(3))) - ((gamma2 + mu) * y(3)),...

gamma1 * y(2) + gamma2 * y(3) ]; % system function

for i = 1:n-1

x( i + 1 ) = x(i) + h;

if (i >= 1) && (i < T);

tau(i) = tau0;

elseif (i >= T) && (i <= TT);

tau(i) = tau0*exp(-alpha*i);

else(i > TT);

tau(i) = tau1;

end

d1 = h * fcn(x(i), y(i, :));

d2 = h * fcn(x(i), y(i, :) + d1 / 2);

d3 = h * fcn(x(i), y(i, :) + d2 / 2);

d4 = h + fcn(x(i), y(i, :) + d3);

y(i+1, :) = y(i, :) + ((d1 + d2 + d3 + d4)* (h / 6));

end

figure(1)

plot(x,y(:,3),'red')

hold on

%%%%%%%%%%%%%%%%%%

clear all

clc

clf

% Initial Value and time step

a = 0; % Lower limit of Integration from 21 Oct 2020

b = 700; % Upper limit of Integration at 20 Oct 2021

h = 0.5; % h = delta_x

n = ((b-a)/h); % no. of points

T = 70;

TT = 100;

tau0 = 2*10^-9;

tau1 = 1.41*10^-9;

alpha = 0.1;

gamma1 = 1/10;

gamma2 = 1/15;

mu = 1/50;

y10 = 8.18*10^7;

y20 = 5.0604*10^3;

y30 = 4.4876*10^3;

y40 = 4590;

y = zeros(n, 4);

x = zeros(n, 1);

y(1, :) = [y10; y20; y30; y40];

x(1) = a;

tau(1) = tau0;

fcn = @(x, y) [-tau(1) * y(1) * (y(2) + y(3)),...

alpha * tau(1) * y(1) * (y(2) + y(3)) - gamma1 * y(2),...

((1-alpha) * tau(1) * y(1) * (y(2) + y(3))) - ((gamma2 + mu) * y(3)),...

gamma1 * y(2) + gamma2 * y(3) ]; % system function

for i = 1:n-1

x( i + 1 ) = x(i) + h;

if (i >= 1) && (i < T);

tau(i) = tau0;

elseif (i >= T) && (i <= TT);

tau(i) = tau0*exp(-alpha*i);

else(i > TT);

tau(i) = tau1;

end

d1 = h * fcn(x(i), y(i, :));

d2 = h * fcn(x(i), y(i, :) + d1 / 2);

d3 = h * fcn(x(i), y(i, :) + d2 / 2);

d4 = h + fcn(x(i), y(i, :) + d3);

y(i+1, :) = y(i, :) + ((d1 + d2 + d3 + d4)* (h / 6));

end

figure(1)

plot(x,y(:,3),'cyan')

hold on

clear all

clc

clf

% Initial Value and time step

a = 0; % Lower limit of Integration from 21 Oct 2020

b = 700; % Upper limit of Integration at 20 Oct 2021

h = 0.5; % h = delta_x

n = ((b-a)/h); % no. of points

T = 70;

TT = 100;

tau0 = 2*10^-9;

tau1 = 1.41*10^-9;

alpha = 0.45;

gamma1 = 1/10;%7.31;

gamma2 = 1/15;%0.11;

mu = 1/50;%1.26;

y10 = 8.18*10^7;

y20 = 5.0604*10^3;

y30 = 4.4876*10^3;

y40 = 4590;

y = zeros(n, 4);

x = zeros(n, 1);

y(1, :) = [y10; y20; y30; y40];

x(1) = a;

tau(1) = tau0;

fcn = @(x, y) [-tau(1) * y(1) * (y(2) + y(3)),...

alpha * tau(1) * y(1) * (y(2) + y(3)) - gamma1 * y(2),...

((1-alpha) * tau(1) * y(1) * (y(2) + y(3))) - ((gamma2 + mu) * y(3)),...

gamma1 * y(2) + gamma2 * y(3) ]; % system function

for i = 1:n-1

x( i + 1 ) = x(i) + h;

if (i >= 1) && (i < T);

tau(i) = tau0;

elseif (i >= T) && (i <= TT);

tau(i) = tau0*exp(-alpha*i);

else(i > TT);

tau(i) = tau1;

end

d1 = h * fcn(x(i), y(i, :));

d2 = h * fcn(x(i), y(i, :) + d1 / 2);

d3 = h * fcn(x(i), y(i, :) + d2 / 2);

d4 = h + fcn(x(i), y(i, :) + d3);

y(i+1, :) = y(i, :) + ((d1 + d2 + d3 + d4)* (h / 6));

end

figure(1)

plot(x,y(:,3),'green')

hold on

clear all

clc

clf

% Initial Value and time step

a = 0; % Lower limit of Integration from 21 Oct 2020

b = 700; % Upper limit of Integration at 20 Oct 2021

h = 0.5; % h = delta_x

n = ((b-a)/h); % no. of points

T = 70;

TT = 100;

tau0 = 2*10^-9;

tau1 = 1.41*10^-9;

alpha = 0.5;

gamma1 = 1/10;%7.31;

gamma2 = 1/15;%0.11;

mu = 1/50;%1.26;

y10 = 8.18*10^7;

y20 = 5.0604*10^3;

y30 = 4.4876*10^3;

y40 = 4590;

y = zeros(n, 4);

x = zeros(n, 1);

y(1, :) = [y10; y20; y30; y40]; %

x(1) = a;

tau(1) = tau0;

fcn = @(x, y) [-tau(1) * y(1) * (y(2) + y(3)),...

alpha * tau(1) * y(1) * (y(2) + y(3)) - gamma1 * y(2),...

((1-alpha) * tau(1) * y(1) * (y(2) + y(3))) - ((gamma2 + mu) * y(3)),...

gamma1 * y(2) + gamma2 * y(3) ]; % system function

for i = 1:n-1

x( i + 1 ) = x(i) + h;

if (i >= 1) && (i < T);

tau(i) = tau0;

elseif (i >= T) && (i <= TT);

tau(i) = tau0*exp(-alpha*i);

else(i > TT);

tau(i) = tau1;

end

d1 = h * fcn(x(i), y(i, :));

d2 = h * fcn(x(i), y(i, :) + d1 / 2);

d3 = h * fcn(x(i), y(i, :) + d2 / 2);

d4 = h + fcn(x(i), y(i, :) + d3);

y(i+1, :) = y(i, :) + ((d1 + d2 + d3 + d4)* (h / 6));

end

figure(1)

plot(x,y(:,3),'yellow')

hold on

clear all

clc

clf

% Initial Value and time step

a = 0; % Lower limit of Integration from 21 Oct 2020

b = 700; % Upper limit of Integration at 20 Oct 2021

h = 0.5; % h = delta_x

n = ((b-a)/h); % no. of points

T = 70;

TT = 100;

tau0 = 2*10^-9;

tau1 = 1.41*10^-9;

alpha = 0.95;

gamma1 = 1/10;%7.31;

gamma2 = 1/15;%0.11;

mu = 1/50;%1.26;

y10 = 8.18*10^7;

y20 = 5.0604*10^3;

y30 = 4.4876*10^3;

y40 = 4590;

y = zeros(n, 4);

x = zeros(n, 1);

y(1, :) = [y10; y20; y30; y40];

x(1) = a;

tau(1) = tau0;

fcn = @(x, y) [-tau(1) * y(1) * (y(2) + y(3)),...

alpha * tau(1) * y(1) * (y(2) + y(3)) - gamma1 * y(2),...

((1-alpha) * tau(1) * y(1) * (y(2) + y(3))) - ((gamma2 + mu) * y(3)),...

gamma1 * y(2) + gamma2 * y(3) ]; % system function

for i = 1:n-1

x( i + 1 ) = x(i) + h; % Not: "x(i+1) = 1*h", but maybe: "i * h"

if (i >= 1) && (i < T);

tau(i) = tau0;

elseif (i >= T) && (i <= TT);

tau(i) = tau0*exp(-alpha*i);

else(i > TT);

tau(i) = tau1;

end

d1 = h * fcn(x(i), y(i, :));

d2 = h * fcn(x(i), y(i, :) + d1 / 2);

d3 = h * fcn(x(i), y(i, :) + d2 / 2);

d4 = h + fcn(x(i), y(i, :) + d3);

y(i+1, :) = y(i, :) + ((d1 + d2 + d3 + d4)* (h / 6));

end

figure(1)

plot(x,y(:,3),'magenta')

hold off

Answer 1

[KSSV]

You have used clf....remove this

[Meor Hasan Meor Jumat]

which part? all?

[KSSV]

clf - clears the figures .

If you are running each function seperately.....as there is clear all your hold on gets invalid.