how to assign vpasolve results to a vector?

So i did some coding but vpasolve is just giving out single values. How do i assignt those values to a vector?

Here ist the code im wirking with:

clear all

clc

% Parameter

A_1 = 8.23714;

A_2 = 8.19625;

B_1 = 1592.864;

B_2 = 1730.63;

C_1 = 226.184;

C_2 = 233.426;

c1 = 1.701;

c2 = 0.9425;

p = 1022.48; % [mbar]

T = 78.3; % [°C]

% x1 als symbolische variable

syms x1

% Berechnung g1 and g2

g1 = exp((c1.*((1-x1)).^2)./(((1-x1)+(c1/c2).*x1).^2));

g2 = exp((c2.*(x1).^2)./((x1+(c2/c1).*(1-x1)).^2));

for j=1:217

T=T+0.1

% Berechnung p1 and p2

p1 = 10^(A_1-(B_1./(T+C_1)));

p2 = 10^(A_2-(B_2./(T+C_2)));

% Funktion

eqn = (g1.*p1.*x1) + (g2.*p2.*(1-x1)) - p == 0;

% symbolische Lösung der Gleichung

results = vpasolve(eqn, x1)

end

Answer 1

[Dyuman Joshi]

A_1 = 8.23714;
A_2 = 8.19625;
B_1 = 1592.864;
B_2 = 1730.63;
C_1 = 226.184;
C_2 = 233.426;
c1 = 1.701;
c2 = 0.9425;
p = 1022.48;    % [mbar]
T = 78.3;         % [°C]
% x1 als symbolische variable
syms x1
% Berechnung g1 and g2
g1 = exp((c1.*((1-x1)).^2)./(((1-x1)+(c1/c2).*x1).^2));
g2 = exp((c2.*(x1).^2)./((x1+(c2/c1).*(1-x1)).^2));


%%Number of iteration
n = 217;

%%Preallocate the output array
results = zeros(1,n);

for j=1:n
        T=T+0.1;
        
    % Berechnung p1 and p2
    p1 = 10^(A_1-(B_1./(T+C_1)));
    p2 = 10^(A_2-(B_2./(T+C_2)));
    
    % Funktion
    eqn = (g1.*p1.*x1) + (g2.*p2.*(1-x1)) - p == 0;
    % symbolische Lösung der Gleichung
    %%Store the result in the respective element
    results(j) = vpasolve(eqn, x1);
end

%Display the output
results

results = 1×217

0.8657 0.8048 0.7681 0.7386 0.7131 0.6900 0.6688 0.6489 0.6301 0.6122 0.5950 0.5784 0.5624 0.5469 0.5318 0.5171 0.5027 0.4887 0.4750 0.4616 0.4485 0.4357 0.4232 0.4109 0.3989 0.3872 0.3758 0.3647 0.3539 0.3435

[Vincent Nent]

Thank you very much

Answer 2

[Samay Sagar]

You can initialize an empty array and append the results to it. You can implement the same as following :

res_vector=[];
results = vpasolve(eqn, x1);
res_vector=[res_vector results]

[Dyuman Joshi]

Dynamically growing arrays is not a good coding practice. It is not efficient.

Refer to Preallocation - "for and while loops that incrementally increase the size of a data structure each time through the loop can adversely affect performance and memory use. Repeatedly resizing arrays often requires MATLAB® to spend extra time looking for larger contiguous blocks of memory, and then moving the array into those blocks. Often, you can improve code execution time by preallocating the maximum amount of space required for the array."