Babylonian algorithm - square root of a number

Dear all,

I am trying to bulid a function that should calculate the square root o a positive number. Unfortunatly I cannot run the code as expected.

Does anyone spot the error? Thank you in advance.

function y=sqrtB(x)
% It returns a row vector containing the approximation of the square roots of the elements of x.
% Using the Babylonian method. 
% with precision 10^-10
%
% INPUT     x ... 1xn vector of positive numbers
%
% OUTPUT    y ... 1xn vector of square roots of x

%format long

xn=x./2;  %starting number

err=abs(xn-x./xn);  % the absolute error

while any(err > 1e-10)     % upper bundary for the absolute error (vector compatible)
    xn = 0.5 .* (xn + x./xn);
    err=abs(xn-x./xn);
    %disp(err);
end

y=xn;
disp(x);
disp(y);

end

Answer 1

[Stephan]

What is the problem - works for me:

y = sqrtB([16 4 9]);

function y=sqrtB(x)
% It returns a row vector containing the approximation of the square roots of the elements of x.
% Using the Babylonian method.
% with precision 10^-10
%
% INPUT     x ... 1xn vector of positive numbers
%
% OUTPUT    y ... 1xn vector of square roots of x
%format long
xn=x./2;  %starting number
err=abs(xn-x./xn);  % the absolute error
while any(err > 1e-10)     % upper bundary for the absolute error (vector compatible)
  xn = 0.5 .* (xn + x./xn);
  err=abs(xn-x./xn);
  %disp(err);
end
y=xn;
disp(x);
disp(y);
end

i get correct results by calling the function properly.

[Francesco Rossi]

I get this error message: Undefined function 'fomat' for input arguments of type 'char'.

if I run it (i.e.)

format long

sqrtB(100)

[James Tursa]

Did you really misspell 'format' as 'fomat'?

[Stephan]

what shows up if you enter the following in the command window:

which format -all

[Francesco Rossi]

OMG, thank you!!