How to create a function in matlab

Hello I need to create a function for finding out the intial values of a logistic map. The logistic map is given by

      x(ii+1)=mu*x(ii)*[1-x(ii)]

where all the values lie between the (0,1).

Where x(1) and mu can b found out from the following formulas

      x(1)=(S+R1+R2) (mod1)
      mu= 3.9+ [((S+R2)(mod1))/10]

where

      R1=(k1k2..k6)/(2^23)
      R2=(k7k8..k12)/(2^23)
      S=(k20k19..k13)/100
Where 
      K=k1k2...k20 is the key that im going to be using.it is a 20 bit key where each bit has to be accessed for generating R1 R2 and S

I'll be doing this four times for a different key each. So i thought of writng a function that gets the key from the user and performs the sequence generation using logistic map. Please help. thanks in advance.

[Stephen23]

Note you should use not name your variables using i or j, as these are the names of the inbuilt imaginary unit .

[Abirami]

oh okay sir...Thank you..i will change it..

Answer 1

[Stalin Samuel]

function [x] = logistic(k)

 R1=(k1k2..k6)/(2^23)
      R2=(k7k8..k12)/(2^23)
      S=(k20k19..k13)/100
      x(1)=(S+R1+R2) (mod1)
      mu= 3.9+ [((S+R2)(mod1))/10]
      x(i+1)=mu*x(i)*[1-x(i)]
end

[Stephen23]

When I run this code I get an error as follows:

>> logistic(3)
??? Error: File: logistic.m Line: 2 Column: 9
Unexpected MATLAB operator.

It appears that this code was not tested, as it contains so many bugs and syntax errors. This is not usable MATLAB code:

• referencing variables before they have been defined (eg k1,k2,k6,.etc)
• using ellipses to indicate a range