Conversion to double from function_handle is not possible.

Hi,

I am having a problem with the syms function in matlab and I was wondering if anyone could help. The help would be greatly appreciated.

The code is to caclulate the bubblepoint of a mixture which contains n components.

The beginning of the code can be seen below. The last part of the code is where the error occurs. The error is: Conversion to double from function_handle is not possible, and occurs in the line y(1,i) =@(T) x(1,i).*(10.^(logP(T)./P_total)); .

P_total = input('Please enter the total pressure in mm Hg: \n');
n = input('Please enter the number of components:\n');
x = zeros(1, n);            % Liquid phase mole fractions
y = zeros(1, n);            % Vapour phase mole fractions
load Antoine_coefficients.txt            % reading in the file which contains the Antoine Coefficients of the components
fprintf(' 1 = Acetaldehyde\n 2 = Acetic Acid \n 3 = Acetone \n 4 = Acetylene \n 5 = Ammonia\n 6 = Argon\n 7 = Benzene \n')
for ite = 1: n
    fprintf('Please enter the corresponding number for the component %i in the feed stream: \n', i);
    comp(i) = input(' ');
    data1 = Antoine_coefficients(comp(i),:);
    a(i) = data1(1);
    b(i) = data1(2);
    c(i) = data1(3);
end
for i = 1:1:n
    fprintf('Please input the liquid phase mole fraction of component %i: \n', i);
    x(1, i) = input(' ');
end
% bubble point temp. calc
syms T
T = sym('T', [1 n]);
ytotal = zeros(1, n);
for  i = 1:n
    logP = @(T)  a(i) - (b(i)./(T+c(i)));
    y(1,i) =@(T)  x(1,i).*(10.^(logP(T)./P_total)); 
    ytotal = ytotal + y(i);
    y(i) = y(i+1);
end

Answer 1

[Steven Lord]

Non-scalar arrays of function handles are not allowed. Either make the function handle and use it without storing it for long-term use or make a cell array of function handles.

y = zeros(1, 10);
g = cell(1, 10);
for k = 1:10
    f = @(x) x.^k;
    y = y + f(1:10);
    g{k} = @(x) k*x;
end
format longg
y

y = 1×10

10 2046 88572 1398100 12207030 72559410 329554456 1227133512 3922632450 11111111110

g{5}(6) % 30

ans = 
    30

[Kate Kirwan]

Thanks very much for the help, I really appreciate it!