八度：在其功能文件中调用一个功能

Question

Is calling a function in the file functions definition file possible? I am pretty curious about it. Thanks for your answers.

%It would prove efficient to write a function since we are going
%to do the same thing twice.
function fleas(N);
clear totalflea;
%The below vector is for plotting purposes only.
Nvector = linspace(0, N, N + 1);
%Define the flea vector as follows:
%The value 0 correspond to a fleas residing on dog B 
%(Burnside);thus initially all fleas are on Burnside.
totalflea(1) = 0;
%Since initially we do not have any fleas on Burnside.
fv = zeros(1,50);
for n = 1 : N;
k = randi(50);
%The above code generates a random integer between 1 and 50.
%The code has been implemented in Octave 3.4.
switch fv(k)
    case 0
    fv(k) = 1;
    case 1
    fv(k) = 0;
end
%The above statement changes the values of fv(k) depending
%on its initial value. The possible values are 0 or 1.
totalflea(n + 1) = sum(fv);
endfor
%The following lines are there to depict two standard deviations away
%from the mean value of 25. The standard deviation of a discrete binomial
%variable is found in "Introduction to Probability" by Bertsekas and
%Tsitsiklis. The 2 SD barrier is as follows:
sdp = ones(1, N + 1)*(25 + 2*sqrt(50)/2);
sdm = ones(1, N + 1)*(25 - 2*sqrt(50)/2);
plot (Nvector, totalflea, Nvector, sdp , "1", Nvector, sdm, "1");
% "1" is supplied as an optional argument to determine the color 
%of the graph.
xlabel('Time Steps')
ylabel('Fleas on Anik')
xrange 
endfunction

This works fine, yet when I append the line fleas(500) for example at the end of the file I get a parse error. When I add it at the beginning of the file I get the following error:

warning: function 'fleas' defined within script file '/home/ongun/Desktop/Dropbox/Computational Physics/Codes/fleas.m'
error: invalid use of script /home/ongun/Desktop/Dropbox/Computational Physics/Codes/fleas.m in index expression

Answer 1

In octave you can either create a function file or a script file. I will simplify a little bit:

For every function create a file with the same name. begins with function ... ends with endfunction

If you want to call functions, you can either use the command line or crate a script file. Script files do not contain any function definition, simply write the commands you want to execute.

Thus you have to create a second file containing fleas(500) or call it from command line.