Why am I getting Error using nargin? Tried to run the below code but only getting the error using nargin. I attempted everything

%% SEDIMENTATION INTERFACE

function dh_s = Emul(t,h)

nd = 1000; % No. of Droplets
% D = 300; % Droplets Diameter of Sphere in microns
Vol = 900; % Liquid volume of emulsion (ml)
l = 0.5; % Mean Distance between droplets 
alpha = 0.08; % Empirical Collision Effiency Parameter
D0 = 300; % Initial Droplet Diameter (microns)
Pr = 0.74; % Volume Fraction



Pr0 = ((nd*pi*D0^3)/6)/Vol; % Initial Volume Fraction of droplet
Prm = ((nd*pi*((D0+l)^3))/6)/Vol; % Maximum Volume Fraction of droplet

delrho = rho_B1 - rho_O1; % difference between the dispersed  water and continuous oil phase

Vsto = (delrho*g*(D0^2))/18*mu1; % Settling Velocity of Hard Spheres (stoke's velocity)
fPr = (1-Pr0)^5.3; % Dimensionless

%D = sqrt((2/3)*alpha*((Vsto*fPr)/(((Prm/Pr0)^1/3)-1))*(D0*t)+(D0^2)); % evolution of average diameter versus time


K1 = ((2/3)*alpha*((Vsto^2)/D))*((fPr^2)/((Prm/Pr)^1/3)-1);

dh_s = -K1*t-(Vsto*fPr);

Command Window Code and results:

Any assistance is greatly appreciated.

Answer 1

[Davide Masiello]

When you call ode45, you shold use the function's name (i.e. Emul).

In the example above you are inputting 'Emulsion', which is probably the name of a another script you have samed in your current folder.

Just write

[t,h] = ode45('Emul',t,h0);

[Walter Roberson]

[t, h] = ode45(@Emul, t, h0);

would be better.

[Davide Masiello]

Agreed, the former is old syntax.

[Matthew Charles]

No problem, Thank you very much!

[Davide Masiello]

Please consider accepting the answer if it helped.