How to solve the following error in matlab "Error using semilogy: Invalid second data argument"?!

Hello!

I am trying to run the following code about numerical integration in Matlab, but I get an error that I do not understand. The error is:

"Error using semilogy

Invalid second data argument".

What is causing this error in the code?

Thank you.

close all;clear;
klin1=1; klin2=0.5; 
variance1 = sqrt(1/(2.*(klin1+1)));

mean1=sqrt(1.*klin1/(klin1+1));
variance2 = sqrt(1/(2.*(klin2+1)));
 
mean2=sqrt((1.*klin2)/(klin2+1));

 
avgdb= 30;
avg=10.^(avgdb./10);
 
fx=@(x) 0;

 for q=0:15
for w=0:15
c2=(1./(4.*variance1.^2.*variance2.^2)).*exp(-mean1.^2/(2.*variance1.^2)).*exp(-mean2.^2./(2.*variance2.^2)).*(1./((factorial(q).^2).*(factorial(w)).^2))*(((mean1)./(2.*variance1.^2)).^(2.*q)).*(((mean2)./(2.*variance2.^2)).^(2.*w))*((1./(2.*(variance2.^2))).^(q-w)).*(1./avg).^((q+1));
f2=@(x) c2.*(1./(2.*x)).^(-q-1).*MeijerG({[1+q-w,1,q+2], []}, {[], [q+1]}, ((avg./(2.*x)).*(4.*variance1.^2.*variance2.^2)));
fx=@(x) fx+f2;
end
 end
 
outage=@(x) 1-fx.*fx;
P=@(x) (exp(-x)*x^(-0.5)*outage);
pe=@(x) (1/(2*sqrt(pi)))*integral(P,1,100);
semilogy(avgdb,pe);

By the way the MeijerG function i am using is the following:

function y = MeijerG(a,b,z)
% MeijerG
% 	A wrapper for MATLAB symbolic library implementation of the 'MeijerG' G^{m,n}_{p,q}(...|z) function.
%   It uses Maple with MATLAB 2008a or earlier; muPad with later versions. 
%
%   Syntax    : 
%       MeijerG({[a_1,...a_n],[a_n+1,...a_p]},{[b_1,...b_m],[b_m+1,...b_q]},z)
%   Input arguments : 
%       a - {[a_1,...a_n],[a_{n+1},...a_p]}
%       b - {[a_1,...a_m],[a_{m+1},...a_q]}
%       z - matrix of (possibly complex) numbers
%   Output:
%       y - has same dimensions as 'z'
%
%   Notes:
%   1.) For invalid arguments, 'double' function for converting results back
%   from symbols would return an error.
%   'MeijerG' catches the error, displays a warning, and sets corresponding
%   position of 'y' to 'nan'.
%   2.) 'double' to 'string' conversion used for forming the symbolic
%   expressions causes a precision loss, and possibly, round of errors.
%   3.) Sometimes, even the slightest changes to arguments 
%   could produce unacceptable results.
%       e.g.
%       >> MeijerG({[1,1], []},{1, 1},[1,2,3])
%       ans =
%           NaN   0.666666666666667   0.750000000000000
%       >> MeijerG({[1,1], []},{1, 1},[1+1e-5,2,3])
%       ans =
%           0.500002499987500   0.666666666666667   0.750000000000000
%       Here the second result appears correct, since
%            MeijerG({[1,1], []},{1, 1},z ) = z/(z+1)
%   Please let me know if such issues can be circumvented.
%
%   Author        : Damith Senaratne, (http://www.damiths.info)
%   Released date : 16th August 2011 

if verLessThan('matlab','7.7.0')
    useMaple = true;
    maple('MeijerGi := sqrt(-1);');
else
    useMaple = false;
    SE = symengine;
    evalin(SE,'MeijerGi := sqrt(-1)');
end
% Note: Given the performance penalty and other implications,
% the symbolic engine is not reset within 'MeijerG'.
% Hence, the choosing a simple identifier for imaginary unit (e.g. 'i')
% appears difficult. 
% The identifier 'MeijerGi' is chosen above hoping that it won't conflict
% with any already defined symbolic variable.
    
% extract the arguments
a1 = a{1}; a2 = a{2};
b1 = b{1}; b2 = b{2};

a1 = a1(:); a2 = a2(:);
b1 = b1(:); b2 = b2(:);

zvec = z(:); % vectorize (to make the computation independent of the dimensions)
y = zeros(size(zvec));
for k=1:length(y)
    % iterate for each element of 'z'!
    if imag(z(k))>=0
        zStr = sprintf('%g + MeijerGi* %g',real(z(k)),imag(z(k))); 
    else
        zStr = sprintf('%g - MeijerGi* %g',real(z(k)),abs(imag(z(k)))); 
    end
   
    if useMaple
        cmd = sprintf('evalf(MeijerG([%s,%s],[%s,%s],%s))',intVecToStr(a1),intVecToStr(a2),intVecToStr(b1),intVecToStr(b2),zStr);
        [r,s] = maple(cmd);
        
        if s ~= 0
            warning('MeijerG: failed evaluating for k = %d',k);
            y(k) = nan;
        else
            r = str2double(r);
            y(k) = r(1);
        end
    else
       expr = sprintf('meijerG([%s,%s],[%s,%s],%s)',intVecToStr(a1),intVecToStr(a2),intVecToStr(b1),intVecToStr(b2),zStr);
       [r,s] = evalin(SE,expr); 
       if s ~= 0
            warning('MeijerG: failed evaluating for k = %d',k);
            y(k) = nan;     
       else
            try
                y(k) = double(r(1));                  
            catch err
                warning('MeijerG: failed evaluating for k = %d',k);
                y(k) = nan;
            end
       end
    end
end
y = reshape(y,size(z));

% -----------------------
% function: intVecToStr
% -----------------------
% converts elements of an integer array 'a' to a string
function s = intVecToStr(a)
s = ['[', sprintf(' %ld,',a)];
s = [s(1:end-1), ' ]'];

[Geoff Hayes]

Deema42 - I don't think that you can pass a function handle p3 as the second input to the semilogy function. At least that what the error message in my version of MATLAB is implying...as does the documentation for semilogy. Why are you doing so here?

[Deema42]

@Geoff Hayes What do you mean by function p3?

[David Wilson]

It seems that pe is an anonymous function, so you need to give it an argument.

semilogy(avgdb,pe(x))

But I suspect that's not your only problem. The variable avgdb is a scalar. Is that what you want to plot? A single point?

Also I'm a bit unclear about things like:

fx=@(x) fx+f2;

I think you mean

fx=@(x) fx(x) + f2(x)

You'll need to correct quite a bit of that type of error.