How to create a table to show the results of a function code?

function s = snlnewt(f,J,X0,eps,itmax)

% f is a vector of anonymous function;

% J is the Jacobian matrix of f;

% X0 is the vector that contains the initial approximation;

% eps is the tolerance choosen;

% itmax is the max iteration allowed to run the code.

%% Nonlinear system %%

% x^2 + y^2 = 1

% x^2 - y = 0

% inicial guess x=1 and y=0.9

%eps = 10^-4

%itmax = 10

% i'm calling this function by snlnewt(@(x) [x(1)^2+x(2)^2-1;x(1)^2-x(2)],@(x) [2*x(1) 2*x(2); 2*x(1) -1],[1; 0.9], 10^-4, 10)

it = 1; % first iteraction

xo = X0; % xo assumes the values of the initial approximation

dx = eliminacao_gauss( J(xo), -f(xo) ) % dx is the solution of the linear sistem J\(-f) whitch is solved by gauss method

xk = xo + dx % giving xk the most recent value on the actual iteration

erro = norm(xk-xo)/max(abs(xk))

%% repeat the process until the error (eps) is reached

while erro >eps

it = it + 1;

xo=xk;

dx = eliminacao_gauss( J(xo), -f(xo) )

xk = xo + dx

if it == itmax %stop the code

break

end

end

p=xk % final solution

disp('Solução do SNL')

disp(p)

disp('Iterações')

disp(it) % disp the total number of iterations

end

How can I create a table to show the data of each iteration like

it | dx | xk | erro ??

Never mind any mistakes in english, I'm not a native.

Answer 1

[Star Strider]

Subscript the variables so they are column vectors, then put them in the table and return the table as one of the outputs (or perhaps the only output).

while erro >eps
    itv(:,it) = it;
    xo(:,it)=xk;
    dx(:,it) = eliminacao_gauss( J(xo), -f(xo) );
    xk(:,it) = xo + dx;
    erro(:,it) = norm(xk-xo)/max(abs(xk));
    if it == itmax %stop the code 
        break
    end
    it = it + 1;
end
s = table(itv,dx,xk,erro);

Note that ‘s’ is not otherwise defined anywhere, so I assigned the table array to it.

.

[Eduardo Fornazieri]

For some reason, there was a error message on the command window saying

" Error using tabular/countVarInputs (line 267)

All variables must have the same number of rows.

Error in table (line 213)

[numVars,numRows] = tabular.countVarInputs(varargin); "

Anyway, I've done some ajustments in your reply and the final code is:

while erro >eps

itv(:) = it;

xo(:)=xk;

dx(:) = eliminacao_gauss( J(xo), -f(xo) );

xk(:) = xo + dx;

erro(:) = norm(xk-xo)/max(abs(xk));

if it == itmax %stop the code

break

end

p(it,:) = table(itv',dx',xk',erro',...

'VariableNames',{'k' 'dx' 'xk' 'erro'});

it = it + 1;

end

s = p;

by now, it's working the way I was expecting. Thank you, bro! I couldn't do it before without your help!

[Star Strider]

As always, my pleasure!

.