Input Argument is "undefined"

Currently I am trying to fit a function to a set of data by solving for two parameters using the FMINSEARCH command.

This is the code:

function sse = LogisticRegression2(x,t,Actual_Output)

fileName = 'Altered Intensity data(red)_2009-01-16 to -22';'G-SNP20 red';

a = xlsread(fileName);

t = a(:,1);  %t values of the data set I am trying to fit

I = a(:,2)/max(a(:,2)); %the y coordinate data points of the data set

lambda = x(1); %one of the parameters
Km = x(2); %the second parameter

Rt = 5e-11;

cm0 = 3e-9;

epsilon = Rt/cm0;

L1 = (1+Km+epsilon)/(2*epsilon)*(1+sqrt(1-(4*epsilon)/(1+Km+epsilon)^2));

L2 = (1+Km+epsilon)/(2*epsilon)*(1-sqrt(1-(4*epsilon)/(1+Km+epsilon)^2));

Fitted_Curve = (L1*L2*(1-exp(-epsilon*(L1-L2)*t*60/lambda)))/(L1-L2*exp(-epsilon*(L1-L2)*t*60/lambda));

Error_vector = Fitted_Curve-Actual_Output;

sse = sum(Error_vector.^2);

Starting=rand(4e3,.01); 

options=optimset('Display','iter');

x = fminsearch(@LogisticRegression,Starting,options,t,I);

% To check the fit
plot(t,I,'*')

hold on

plot(t,x(1)*exp(-x(2)*t),'r')

However I am getting an error of

"Input argument "x" is undefined.

Error in ==> LogisticRegression2 at 7
lambda = x(1); %one of the parameters"

I am not sure what I did wrong. If anyone knows what went wrong I would greatly appreciate it. Thanks

Thomas

[Jan]

Please format your code - follow the "Markup help" link for details.

Answer 1

[Jan]

It looks like you are calling LogisticRegression2 without inputs, but this function needs 3 inputs. The Getting Started chapters of the documentation explain the usage of functions exhaustively.

Answer 2

[Thomas]

Aren't I calling LogisticRegression2 with inputs (x,t,Actual_output)? Where x is defined by the vectors lambda = x(1) and Km = x(2)?

[Jan]

I cannot answer the question, how you are calling this function - but you can! Please post the line, which calls the function. The error message says, that the first input argument x has not been defined.

You have t in the inputs, but overwrite it in the function.