error 'not enough input arguments" at line with dx..

function waterTableHt(h0,hL,L,n)

% Determine the height of the water table in a phreatic aquifer % input

% h0 = height of water table at one point

% hL = height of water table at another point

% L = length between the two points of known water table

% n = number of points for finite difference

%output

% no output, plot the height of the water table

% Initialization

dx=L/(n+1);

hmid =(h0 + hL)/2; %average height of the water table

N =.0001;

K =1;

MU =(N*dx^2)/(hmid*K);

A =zeros(n,n); %set up equations

b =zeros(n,1);

A(1,1)=2+MU; %first equation

A(1,2)=-1;

b(1)= MU + h0;

for i=2:n-1 %equations 2 through n-1

    A(i,i-1)=-1;

    A(i,i)=2+MU;

    A(i,i+1)=-1;

    b(i)=MU*hL;

end

A(n,n-1)=-1; %last equation

A(n,n)=2+MU;

b(n)=MU+hL;

h=A\b; %solve equations

Answer 1

[Adam]

How are you calling your function? If you just click Run then you will obviously get this. That is a function that takes arguments so you need to call it from command line, a script or another function and pass in those arguments.

[laurae1234]

yeah when i input h0,hL,L, and n i still get this error

[Adam]

How are you inputting them because that error doesn't make sense if you are passing the arguments in correctly?

[John BG]

the error has to be in the way you input the parameters to your function, because the following does not return any error:

h0=10
hL=11
L=100
n=280

dx=L/(n+1);
hmid =(h0 + hL)/2; %average height of the water table
N =.0001;
K =1;
MU =(N*dx^2)/(hmid*K);
A =zeros(n,n); %set up equations
b =zeros(n,1);
A(1,1)=2+MU; %first equation
A(1,2)=-1;
b(1)= MU + h0;
for i=2:n-1 %equations 2 through n-1
    A(i,i-1)=-1;
    A(i,i)=2+MU;
    A(i,i+1)=-1;
    b(i)=MU*hL;
end

A(n,n-1)=-1; %last equation
A(n,n)=2+MU;
b(n)=MU+hL;
h=A\b; %solve equations

ignore for a moment the people who tell you that you have to build functions. They tell so because if they see it useful, in the shape of functions it's easier to reuse, by them.

It's good practice, for you, to reach a working script before attempting to write a function of such length.

Regards

John BG

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