Hi please help me correct this error

4 visualizaciones (últimos 30 días)
Abdurahman Itani
Abdurahman Itani el 12 de Oct. de 2017
Editada: Walter Roberson el 14 de Oct. de 2017
this is the error i am receiving while using the jacobian function,
Error using sym/subs>normalize
Inconsistency between sizes of
second and third arguments.
here is my code
------------------------------------------------------------------------
function [func, j] = sysNonlinearEqs(X) % X here is a vector
clc;
x = X(1)
y = X(2)
z = X(3)
%Define F(x)
syms x y z
func(1,1)= x + y - exp(-z); % Row 1 Column 1 of Vector F(x)
func(2,1)= z + x - exp(-y); % Row 2 Column 1 of Vector F(x)
func(3,1)= y + z - exp(-x); % Row 3 Column 1 of Vector F(x)
% Define Jacobian
J = jacobian(func, [x y z])
j = double(subs(J,{x, y, z}, X))
---------------------------------------------------------
i am trying to call my function in this script and the error message pops up
syms X
%global x y z
% Initial Conditions
X0 = [1; 1; 1];
maxiter = 50;
tolx = 1e-6;
%computation using the Newton Raphson Method
X= X0;
xold = X0;
for i = 1:maxiter
[func,j] = sysNonlinearEqs(X);
X = X- inv(j)*func;
err(:,i) = abs(X-xold);
xold = X;
if ( err(:,i) < tolx)
break;
end
end

Respuesta aceptada

Jonathan Chin
Jonathan Chin el 12 de Oct. de 2017
function [func, j] = sysNonlinearEqs(X)
% X here is a vector clc;
% x = X(1); y = X(2); z = X(3) ;
%Define F(x)
syms x y z
func(1,1)= x + y - exp(-z); % Row 1 Column 1 of Vector F(x)
func(2,1)= z + x - exp(-y); % Row 2 Column 1 of Vector F(x)
func(3,1)= y + z - exp(-x); % Row 3 Column 1 of Vector F(x)
% Define Jacobian
J = jacobian(func, [x y z]) ;
j = double(subs(J,{x, y, z}, X(:).')); %<- X here needs to be in row vector format
  2 comentarios
Abdurahman Itani
Abdurahman Itani el 13 de Oct. de 2017
Editada: Abdurahman Itani el 13 de Oct. de 2017
i changed the code now the error is
Conversion to logical from sym is not possible.
Error in Main_Script (line 15) if ( err(:,i) < tolx)
can you please help me there?thank you
Jonathan Chin
Jonathan Chin el 14 de Oct. de 2017
err(:,i) is a system of equations, you might need to evaluate those values

Iniciar sesión para comentar.

Más respuestas (0)

Community Treasure Hunt

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

Start Hunting!

Translated by