not enough input data

I don't understand why MATLAB says to me that there are not enough input data in this code. Can you help me?

function dydt=Step1(t,y)

Q=1000;

F=8;

m=100;

cp=2.5;

Ti=300;

T=y(1);

dTdt=(Q/(m*cp))-(F/m*cp)*(T-Ti);

dydt=[dTdt]';

[Christopher McCausland]

How are you calling this function? I am guessing that you do not pass Step the inputs its looking for (t,y). Here is more information. https://uk.mathworks.com/matlabcentral/answers/53100-not-enough-input-arguments. Let us see how you call the function, there are some other problems that can cause the same issue like MATLAB expecting the input arguments in a specific format.

[Alessandro Papetti]

sure, here it is the call

clc

clear all

close all

format compact

format short g

Q=1000;

F=8;

m=100;

cp=2.5;

Ti=300;

%steady state solution (of T)

Toutss=(Q/(F*cp))+Ti;

tspan=[0: 150];

T0=300;

options=odeset('RelTol',1e-8,'AbsTol',1e-12);

[t,T]=ode15s(@(t,T)Step1(t,T,Q,F,cp,Ti,m),tspan,T0,options);

T1=T(:,1);

tspan=[150 300];

T00=max(T); %è uguale a Toutss

[t1,T2]=ode15s(@(t1,T2)Step2(t1,T2,Q,F,cp,Ti,m),tspan,options);

plot(t,T1,'b',t1,T2,'r');

Answer 1

[Stephan]

Note that i used the same function for step2 like step1 to make it work - replace step2 with the correct function. Also i assumed that T00 is the initial value for step2 - you shpould check this for correctness:

format compact
format short g

% Call nested function
myODE

function myODE
% constants
Q=1000;
F=8;
m=100;
cp=2.5;
Ti=300;

%steady state solution (of T)
Toutss=(Q/(F*cp))+Ti;

% Step 1
tspan=[0,150];
T0=300;
options=odeset('RelTol',1e-8,'AbsTol',1e-12);
[t,T]=ode15s(@Step1,tspan,T0,options);

% Step 2
T1=T(:,1);
tspan=[150 300];
T00=max(T); %è uguale a Toutss
[t1,T2]=ode15s(@Step2,tspan,T00,options);
plot(t,T1,'b',t1,T2,'r');

function dydt=Step1(~,y)
T=y(1);
dTdt=(Q/(m*cp))-(F/m*cp).*(T-Ti);
dydt=dTdt';
end

function dydt=Step2(~,y)
T=y(1);
dTdt=(Q/(m*cp))-(F/m*cp).*(T-Ti);
dydt=dTdt';
end
end