why this equation is not ploting

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shiv gaur 2022-4-1

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1686454-why-this-equation-is-not-ploting

评论： shiv gaur 2022-4-3

在 MATLAB Online 中打开

Tstart = 100;

Tend = 1000.0;

Nt = 2000;

dT = (Tend-Tstart)/Nt;

X0 = 0.3;

Y0 = 0;

Z0 = 0;

N = 20;

k1=1;

k2=2.52;

k3=1;

k4=5;

I=1.5;

s=4;

xr=-1.6;

r=0.01;

T = zeros(Nt+1,1);

X = zeros(Nt+1,1);

Y = zeros(Nt+1,1);

Z = zeros(Nt+1,1);

a = zeros(N+1,1);

b = zeros(N+1,1);

c = zeros(N+1,1);

T(1) = 0.0;

X(1) = X0;

Y(1) = Y0;

Z(1) = Z0;

for j = 2:Nt+1

a(1) = X(j-1);

b(1) = Y(j-1);

c(1) = Z(j-1);

for k = 1:N

a(k+1)=(b(k)-k1*a(k).^3+k2*a(k).^2-c(k)+I)/(k+1);

b(k+1)=(k3-k4*a(k).^2-b(k))/(k+1);

c(k+1)=r*(s*(a(k)-xr)-c(k))/(k+1);

end

x = a(1);

y = b(1);

z = c(1);

for k = 2:N+1

x = x + a(k)*dT^(k-1);

y = y + b(k)*dT^(k-1);

z = z + c(k)*dT^(k-1);

end

T(j) = T(j-1) + dT;

X(j) = x;

Y(j) = y;

Z(j) = z;

end

plot(T,X)

It's not showing the plot! How do I resolve this?

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Image Analyst 2022-4-1

It works for us.

shiv gaur 2022-4-1

编辑：Walter Roberson 2022-4-1

why this is not like that pl match with equation very famous hind marsh

https://en.wikipedia.org/wiki/Hindmarsh%E2%80%93Rose_model

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回答（1 个）

Sam Chak 2022-4-1

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1686454-why-this-equation-is-not-ploting#answer_932464

编辑：Walter Roberson 2022-4-1

在 MATLAB Online 中打开

Hi @shiv gaur

Simulating the Hindmarsh–Rose model requires solving the differential equations using some numerical ode solvers. You can change the parameters in the code below for your study. If you find my Answer is helpful, please vote and Accept.

function Hindmarsh_Rose
close all
clc  
tspan = [0 1000];                % time span of simulation
y0 = [-1.5 -10 2];               % initial values
[t, y] = ode45(@(t, y) odefcn(t, y), tspan, y0);
plot(t, y(:,1), 'linewidth', 1.5)
grid on
xlabel('Time, t [sec]')
ylabel('x(t)')
title('Hindmarsh–Rose Neuronal Bursting Model')
end
function dydt = odefcn(t, y)    % Ordinary Differential Equations
    dydt = zeros(3,1);
    a = 1;
    b = 3;
    c = 1;
    d = 5;
    I = 2;
    r = 0.0021;
    s = 4;
    xR = -8/5;
    dydt(1) = y(2) - a*y(1)^3 + b*y(1)^2 - y(3) + I;
    dydt(2) = c - d*y(1)^2 - y(2);
    dydt(3) = r*(s*(y(1) - xR) - y(3));
end

Result:

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shiv gaur 2022-4-1

编辑：Walter Roberson 2022-4-1

在 MATLAB Online 中打开

this may be the option

now we have use lorenz system using power series the program is given below so here we are applying power series to hindmarsh equation in same way as lorenz

program is here

Tstart = 0.0;

Tend = 1000.0;

Nt = 20000;

dT = (Tend-Tstart)/Nt;

X0 = 0.0;

Y0 = 1.0;

Z0 = 0.0;

N = 20;

SIGMA = 10;

R = 28;

B = 8/3;

T = zeros(Nt+1,1);

X = zeros(Nt+1,1);

Y = zeros(Nt+1,1);

Z = zeros(Nt+1,1);

a = zeros(N+1,1);

b = zeros(N+1,1);

c = zeros(N+1,1);

T(1) = 0.0;

X(1) = X0;

Y(1) = Y0;

Z(1) = Z0;

for j = 2:Nt+1

a(1) = X(j-1);

b(1) = Y(j-1);

c(1) = Z(j-1);

for k = 1:N

SB = 0.0;

SC = 0.0;

for i= 0:k-1

SB = SB + a(i+1)*c(k-i);

SC = SC + a(i+1)*b(k-i);

end

a(k+1) = (SIGMA*(b(k) - a(k)))/k;

b(k+1) = ((R*a(k) - b(k)) - SB)/k ;

c(k+1) = (-B*c(k) + SC)/k ;

end

x = a(1);

y = b(1);

z = c(1);

for k = 2:N+1

x = x + a(k)*dT^(k-1);

y = y + b(k)*dT^(k-1);

z = z + c(k)*dT^(k-1);

end

T(j) = T(j-1) + dT;

X(j) = x;

Y(j) = y;

Z(j) = z;

end

plot(T,Y)

shiv gaur 2022-4-1

编辑：Walter Roberson 2022-4-1

在 MATLAB Online 中打开

from lorenz to apply HM equation

I have use the your value HM equation

the program using power series is right how to match with ode your program with power series program is given below

Tstart = 0;

Tend = 1000.0;

Nt = 2000;

dT = (Tend-Tstart)/Nt;

X0 = -1.5;

Y0 = -10;

Z0 = 2;

N = 200;

k1=1

k1 = 1

k2=3

k2 = 3

k3=1

k3 = 1

k4=5

k4 = 5

I=2

I = 2

s=4;

xr=-1.6;

r=0.0021;

T = zeros(Nt+1,1);

X = zeros(Nt+1,1);

Y = zeros(Nt+1,1);

Z = zeros(Nt+1,1);

a = zeros(N+1,1);

b = zeros(N+1,1);

c = zeros(N+1,1);

T(1) = 0.0;

X(1) = X0;

Y(1) = Y0;

Z(1) = Z0;

for j = 2:Nt+1

a(1) = X(j-1);

b(1) = Y(j-1);

c(1) = Z(j-1);

for k = 1:N

a(k+1)=(b(k)-k1*a(k).^3+k2*a(k).^2-c(k)+I)/(k+1);

b(k+1)=(k3-k4*a(k).^2-b(k))/(k+1);

c(k+1)=r*(s*(a(k)-xr)-c(k))/(k+1);

end

x = a(1);

y = b(1);

z = c(1);

for k = 2:N+1

x = x + a(k)*dT^(k-1);

y = y + b(k)*dT^(k-1);

z = z + c(k)*dT^(k-1);

end

T(j) = T(j-1) + dT;

X(j) = x;

Y(j) = y;

Z(j) = z;

end

plot(T,X)

shiv gaur 2022-4-2

sir you have all the things equation papers so you are req to resolve the problem

shiv gaur 2022-4-3

if any one help appriciation for solving hmarsh using power series

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