i need to solve 7 nonlinear equations with 7 unknowns and error is occurring while compiling the codes

6 visualizaciones (últimos 30 días)
G = 600:100:1200;
x0 = [300;300;300;300;300;300;300];
options = optimset('Display','off');
X(i) = NaN(1,length(G));
for i = 600:length(G)
fsol = fsolve(@(x) solutionsproblem(x,G(i)),x0,options);
X(i) = fsol(1);
end
function F = solutionsproblem(x,G)
Tg1 = 300;
Tg2 = 301.5;
Ta = 305.8;
Tl = 302;
Tf = 302;
Tb = 302;
Th = 300;
F(1) = 0.0425*G + 1.41*10^(-8)*x(2)^(4) + 1.34*x(2) - 9.12*10^(-9)*x(1)^(4) + 341 - 2402.77*x(1) + 2400*Tg1;
F(2) = 0.0204*G - (3.48*10^(-8) + 4.35*10^(-10)*1)*x(2)^(4) + 1.41*10^(-8)*x(1)^(4) + 8.01*10^(-11)* x(4)^(4) + 2.43*10^(-8)*x(3)^(4) + 4.35*10^(-10)*1*x(5)^(4) + 0.55*x(3) + 1.34*x(1) - 2401.87*x(2) + 2400*Tg2;
F(3) = 0.124*G - 4.88*10^(-8)*x(3)^(4) + 2.44*10^(-8)*1*x(2)^(4) + 2.44*10^(-8)*1*x(5)^(4)- 50.938*x(3) + 11.502*x(6) + 1.836* x(2) + 37.60*Ta;
F(4) = 0.011*G - 8.70*10^(-8)*x(5)^(4) + 4.35*10^(-10)*x(3)^(4)+ 4.35*10^(-10)*x(2)^(4) + 0.83*x(6) + 0.112*x(3) + 0.112*x(2) - (1.055 + (112.7/1))*x(5) + (112.7/1)*Tf;
F(5) = 2.17*10^(-3)*G - 1.6*10^(-10)*x(4)^(4) + 8.01*10^(-11)*x(7)^(4) + 8.01*10^(-11)*x(2)^(4) - 69.07*x(4) + 3.77*10^(-4)*x(7) + 0.02*x(3) + 0.02*x(2) + 69*Tl;
F(6) = -52.068*x(6) + 0.412*x(3) + 0.368*x(4)+ 0.368*x(5) + 0.46*x(2) + 50.78*Tb;
F(7)= 3.77*10^(-4)*x(4) + 8.01*10^(-11)*x(4)^(4) + 0.092*x(5) - 1254.1*x(7) - 8.01*10^(-11)*x(7)^(4) + 1254*Th;
end
  3 comentarios
Bindhu PR
Bindhu PR el 8 de Abr. de 2020
Array indices must be positive integers or logical values.
Error in final (line 4)
X(i) = NaN(1,length(G));
THIS IS SHOWN IN COMMAND WINDOW
David Goodmanson
David Goodmanson el 8 de Abr. de 2020
Hi Bindhu,
you have not defined the argument of X. Ordinarily if you had, say, X(b) it would complain about the undefined variable b. Here, unless you have already defined i as something else, it is assuming i = sqrt(-1)

Iniciar sesión para comentar.

Respuesta aceptada

Bindhu PR
Bindhu PR el 12 de Abr. de 2020
Editada: Ameer Hamza el 12 de Abr. de 2020
syms G;
G = 600:100:1200;
x0 = [300;300;300;300;300;300;300];
options = optimset('Display','on');
X = zeros(1,length(G)); % use X, instead of X(i), initialize with zeros
for i = 1:length(G) % start the loop counter from 1
fsol = fsolve(@(x) solutionsproblem(x,G(i)),x0,options);
X(i) = fsol(1);
end
disp(X);
function F = solutionsproblem(x,G)
Tg1 = 300;
Tg2 = 301.5;
Ta = 305.8;
Tl = 302;
Tf = 302;
Tb = 302;
Th = 300;
F(1) = 0.0425*G + 1.41*10^(-8)*x(2)^(4) + 1.34*x(2) - 9.12*10^(-9)*x(1)^(4) + 341 - 2402.77*x(1) + 2400*Tg1;
F(2) = 0.0204*G - (3.48*10^(-8) + 4.35*10^(-10)*1)*x(2)^(4) + 1.41*10^(-8)*x(1)^(4) + 8.01*10^(-11)* x(4)^(4) + 2.43*10^(-8)*x(3)^(4) + 4.35*10^(-10)*1*x(5)^(4) + 0.55*x(3) + 1.34*x(1) - 2401.87*x(2) + 2400*Tg2;
F(3) = 0.124*G - 4.88*10^(-8)*x(3)^(4) + 2.44*10^(-8)*1*x(2)^(4) + 2.44*10^(-8)*1*x(5)^(4)- 50.938*x(3) + 11.502*x(6) + 1.836* x(2) + 37.60*Ta;
F(4) = 0.011*G - 8.70*10^(-8)*x(5)^(4) + 4.35*10^(-10)*x(3)^(4)+ 4.35*10^(-10)*x(2)^(4) + 0.83*x(6) + 0.112*x(3) + 0.112*x(2) - (1.055 + (112.7/1))*x(5) + (112.7/1)*Tf;
F(5) = 2.17*10^(-3)*G - 1.6*10^(-10)*x(4)^(4) + 8.01*10^(-11)*x(7)^(4) + 8.01*10^(-11)*x(2)^(4) - 69.07*x(4) + 3.77*10^(-4)*x(7) + 0.02*x(3) + 0.02*x(2) + 69*Tl;
F(6) = -52.068*x(6) + 0.412*x(3) + 0.368*x(4)+ 0.368*x(5) + 0.46*x(2) + 50.78*Tb;
F(7)= 3.77*10^(-4)*x(4) + 8.01*10^(-11)*x(4)^(4) + 0.092*x(5) - 1254.1*x(7) - 8.01*10^(-11)*x(7)^(4) + 1254*Th;
end
  3 comentarios
Walter Roberson
Walter Roberson el 12 de Abr. de 2020
Editada: Walter Roberson el 12 de Abr. de 2020
X = zeros(length(G), 7); %initialize with zeros
And in loop
X(i, :) = fsol;

Iniciar sesión para comentar.

Más respuestas (2)

Ameer Hamza
Ameer Hamza el 8 de Abr. de 2020
Editada: Ameer Hamza el 12 de Abr. de 2020
It is a common practice to initialize arrays with zeros instead of nan. Correct two lines in your code
syms G;
G = 600:100:1200;
x0 = [300;300;300;300;300;300;300];
options = optimset('Display','off');
X = zeros(numel(G), numel(x0)); % use X, instead of X(i), initialize with zeros
for i = 1:length(G) % start the loop counter from 1
X(i,:) = fsolve(@(x) solutionsproblem(x,G(i)),x0,options);
end
disp(X);
function F = solutionsproblem(x,G)
Tg1 = 300;
Tg2 = 301.5;
Ta = 305.8;
Tl = 302;
Tf = 302;
Tb = 302;
Th = 300;
F(1) = 0.0425*G + 1.41*10^(-8)*x(2)^(4) + 1.34*x(2) - 9.12*10^(-9)*x(1)^(4) + 341 - 2402.77*x(1) + 2400*Tg1;
F(2) = 0.0204*G - (3.48*10^(-8) + 4.35*10^(-10)*1)*x(2)^(4) + 1.41*10^(-8)*x(1)^(4) + 8.01*10^(-11)* x(4)^(4) + 2.43*10^(-8)*x(3)^(4) + 4.35*10^(-10)*1*x(5)^(4) + 0.55*x(3) + 1.34*x(1) - 2401.87*x(2) + 2400*Tg2;
F(3) = 0.124*G - 4.88*10^(-8)*x(3)^(4) + 2.44*10^(-8)*1*x(2)^(4) + 2.44*10^(-8)*1*x(5)^(4)- 50.938*x(3) + 11.502*x(6) + 1.836* x(2) + 37.60*Ta;
F(4) = 0.011*G - 8.70*10^(-8)*x(5)^(4) + 4.35*10^(-10)*x(3)^(4)+ 4.35*10^(-10)*x(2)^(4) + 0.83*x(6) + 0.112*x(3) + 0.112*x(2) - (1.055 + (112.7/1))*x(5) + (112.7/1)*Tf;
F(5) = 2.17*10^(-3)*G - 1.6*10^(-10)*x(4)^(4) + 8.01*10^(-11)*x(7)^(4) + 8.01*10^(-11)*x(2)^(4) - 69.07*x(4) + 3.77*10^(-4)*x(7) + 0.02*x(3) + 0.02*x(2) + 69*Tl;
F(6) = -52.068*x(6) + 0.412*x(3) + 0.368*x(4)+ 0.368*x(5) + 0.46*x(2) + 50.78*Tb;
F(7)= 3.77*10^(-4)*x(4) + 8.01*10^(-11)*x(4)^(4) + 0.092*x(5) - 1254.1*x(7) - 8.01*10^(-11)*x(7)^(4) + 1254*Th;
end
  11 comentarios
Bindhu PR
Bindhu PR el 12 de Abr. de 2020
This is the output I am getting .Can you help me to print output in such a way that for G=600 print values of x(1) to x(7) similaryy for G=600 to 1200.

Iniciar sesión para comentar.


Bindhu PR
Bindhu PR el 13 de Abr. de 2020
what modification in this programe is to be done so that for G=600 the values thus obtained is from x(1) tox(7) this values of x(1) to x(7) is given to G=700 and similarly the values for T are changed
Tg1 = x(1);
Tg2 = x(2);
Ta = x(3);
Tl = x(4);
Tf = x(5);
Tb = x(6);
Th = x(7);
  10 comentarios
Walter Roberson
Walter Roberson el 28 de Abr. de 2020
If you want to print out the values of x(1) to x(7), why not just disp() the values? You have already shown that you know how to use disp(), so we do not understand why you are asking this question. It tends to suggest to us that you want something more complicated than just displaying x(1) to x(7).
I already showed you in https://www.mathworks.com/matlabcentral/answers/516059-i-need-to-solve-7-nonlinear-equations-with-7-unknowns-and-error-is-occurring-while-compiling-the-cod#comment_827486 how to store all of the values as you compute them, and put them into the various named variables; it would be trivial to add appropriate disp() to that. But you seemed to want something else other than what I suggested and did not reply to me, and you did not explain how what you wanted differed from what I suggested to you; it did not seem to be worth my time to keep asking you questions about what you really wanted.
You are getting 7 outputs for each of the 7 values of G. Give us an example of how you would like the output to look.

Iniciar sesión para comentar.

Categorías

Más información sobre Logical en Help Center y File Exchange.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by