what's wrong with this code. why it show error can anyone tell?

Question

Ayesha Altaf 2021-1-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/713233-what-s-wrong-with-this-code-why-it-show-error-can-anyone-tell

回答： Alan Stevens 2021-1-10

function matlab

clc;clear;

%Radioactive decay

y0=[5*10^26;0];

soln = ode23(@f1,[0 8],y0)

t = linspace(0,8,24);

y(:,1)=deval(soln,t,1); %Strontium

y(:,2)=deval(soln,t,2); % Yttrium

figure

plot(t,y(:,1),'-o',t,y(:,2),'--');

hold on;grid on;

legend('Strontium','Yttrium')

end

function dxdt = f1(x,t)

r1 = 0.256;

r2 = 0.127;

dxdt(1) = -r1 * x;

dxdt(2) = -r2 * x;

dxdt =dxdt';

end

function matlab

↑

Error: Function definition not supported in this context. Create functions in code file.

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Answer 1

Alan Stevens 2021-1-10

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/713233-what-s-wrong-with-this-code-why-it-show-error-can-anyone-tell#answer_594658

在 MATLAB Online 中打开

You probably want something like this (don't enclose it with the statement 'function matlab' - that won't work).

Remember to include the build-up of Ytterbium from Strontium, or ytterbium's curve will stay at zero!).

%Radioactive decay
 y0=[5*10^26;0];
 soln = ode23(@f1,[0 8],y0);
 t = linspace(0,8,24);
 y(:,1)=deval(soln,t,1); %Strontium
 y(:,2)=deval(soln,t,2); % Yttrium
 figure
 plot(t,y(:,1),'-o',t,y(:,2),'--');
 grid on
 legend('Strontium','Ytterbium')
 
 function dydt = f1(~,y)
 r1 = 0.256;
 r2 = 0.127;
 dydt(1) = -r1 * y(1);
 dydt(2) = r1*y(1) -r2 * y(2);
 dydt =dydt';
 end