I am having error using ode45 with Inputs must be floats, namely single or double

Question

rastors23 2021-11-17

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1588714-i-am-having-error-using-ode45-with-inputs-must-be-floats-namely-single-or-double

编辑： Walter Roberson 2021-11-27

Hello scholar, I have a code am running and I keep getting this error after several try. what might be the error in my code? Below is the error shown and few lines where the error might have occured. Kindly help

Error using odearguments (line 113)

Inputs must be floats, namely single or double.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

omegap_r = @(r)omegap.*(1-(k_om.*r./a));  
eps = @(r)@(omega) eps_inf - (omegap_r(r).^2./(omega.^2+(1i*omega.*gamma)));
opts = odeset('RelTol',1e-5,'AbsTol',1e-8);
[r,eps_bar] = ode45(@(r,eps_bar)@(omega) (eps(r).(omega)-eps_bar).*(eps_bar+2.*eps(r).(omega))./(r.*eps(r).(omega)),tspan,1,opts);
e_a = eps_bar(end)./eps_bar;
epsilon_e = @(omega) eps2+((3*eps2*f(y)).*((e_a(1)-eps2)./(e_a(1)+2*eps2)));

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Walter Roberson 2021-11-17

在 MATLAB Online 中打开

Please show

whos a eps_inf gamma k_om omega omegap tspan

with tspan being most important for this purpose.

rastors23 2021-11-17

编辑：rastors23 2021-11-17

Sorry for the delay in reply, I went off lab before.

a = 1;

tspan = [0.001,a];

f = linspace(0.01,0.1,5);

y = 1:length(f)

omegap = 2.7E14;

eps2 = 1.77;

eps_inf = 1;

gamma = 1E12;

k_om = 0;

omegap_r = @(r)omegap.*(1-(k_om.*r./a));

eps = @(r)@(omega) eps_inf - (omegap_r(r).^2./(omega.^2+(1i*omega.*gamma)));

opts = odeset('RelTol',1e-5,'AbsTol',1e-8);

[r,eps_bar] = ode45(@(r,eps_bar)@(omega) (eps(r).(omega)-eps_bar).*(eps_bar+2.*eps(r).(omega))./(r.*eps(r).(omega)),tspan,1,opts);

e_a = eps_bar(end)./eps_bar;

epsilon_e = @(omega) eps2+((3*eps2*f(y)).*((e_a(1)-eps2)./(e_a(1)+2*eps2)));

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Answer 1

Steven Lord 2021-11-17

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1588714-i-am-having-error-using-ode45-with-inputs-must-be-floats-namely-single-or-double#answer_833604

在 MATLAB Online 中打开

[r,eps_bar] = ode45(@(r,eps_bar)@(omega) (eps(r).(omega)-eps_bar).*(eps_bar+2.*eps(r).(omega))./(r.*eps(r).(omega)),tspan,1,opts);

The function handle you're passing into ode45 as its first input does not return a numeric value, it instead returns a function handle. This does not satisfy the requirements ode45 imposes on that function, namely that it return a numeric vector.

If you show us the mathematical form of the differential equations you're trying to solve we may be able to offer suggestions for how to modify your ode45 call's first input.

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Steven Lord 2021-11-17

The equation you posted doesn't include omega at all. How does the program "call for omega"?

rastors23 2021-11-27

编辑：Walter Roberson 2021-11-27

在 MATLAB Online 中打开

clc;
clear all;
close all;
h_bar = 1.054560652E-34/1.6E-19;
k_b = 1.3806488E-23/1.6E-19;
syms omega
d = 10E-9;
a = 1;
tspan = [0.001,a];
f = linspace(0.01,0.1,5);
parfor y = 1:length(f)
    T_H = 450;            %T1 
    T_L = 300;            %T2
    Theta_omega_T_L = @(omega,kp) (h_bar*omega/2).*coth((h_bar*omega)/(2*k_b*T_L));
    Theta_omega_T_H = @(omega,kp) (h_bar*omega/2).*coth((h_bar*omega)/(2*k_b*T_H));
    THETA = @(omega,kp) Theta_omega_T_H(omega,kp) - Theta_omega_T_L(omega,kp);
    %..................Effective..............................%
    omegap = 2.7E14;
    eps2 = 1.77;
    eps_inf = 1;       
    gamma = 1E12; 
    k_om = 0.1;
    omegap_r = @(r)omegap.*(1-(k_om.*r./a));  
    eps = @(r) eps_inf - (omegap_r(r).^2./(omega.^2+(1i*omega.*gamma)));
    opts = odeset('RelTol',1.e-5,'AbsTol',1.e-8);
    [r,eps_bar] = ode45(@(r,eps_bar) (eps(r)-eps_bar).*(eps_bar+2.*eps(r))./(r.*eps(r)),tspan,1,opts);
    e_a = eps_bar(end);
    epsilon_e = @(omega) eps2+((3*eps2*f(y)).*((e_a(1)-eps2)./(e_a(1)+2*eps2)));
    kz = @(omega,kp) sqrt((omega/c).^2-kp.^2);
    k_1 = @(omega,kp) sqrt(epsilon_e(omega).*(omega/c).^2-kp.^2);                        
    r_1pp = @(omega,kp)(epsilon_e(omega).*kz(omega,kp)-k_1(omega,kp))./(epsilon_e(omega).*kz(omega,kp)+k_1(omega,kp));
    r_1ss = @(omega,kp)(kz(omega,kp)-k_1(omega,kp))./(kz(omega,kp)+k_1(omega,kp));
    xi_1 = @(omega,kp)((1 - abs(r_1ss(omega,kp)))^2);
    Xi_1 = @(omega,kp) xi_1(omega,kp).*kp.*THETA(omega,kp);
    ymin = @(omega) omega/3e8;
    XI_1 = integral2(Xi_1,1E13,1E15,1E-5,ymin,'RelTol',1E-3)
end