While loop not starting
2 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Karthi Ramachandran
am 22 Jan. 2020
Kommentiert: Karthi Ramachandran
am 23 Jan. 2020
I am trying to implement a newtons method to find the root of a function. When i check manually, (that is checking condition and executing line by line) the value of the function converged to zero in 5 iterations and the value of 'x' also was correct. But when I run the program as whole while doesnt start at all. I dont get any error message either. I am unable to find the mistake. Checked some answers from matlab forum , I am not getting matched solutions.
% The value of the function goes to zero at x = 0.8660
clearvars;clc
f = @(x) 4*x^2 - 3;
h = 0.0001;
x(1) = 0.5;
y(1) = f(x(1));
i = 1;
while (abs(y(i)) < 1e-4)
fprintf('value of current y: %d\n',(y(i))) % to check of loop enters
% just takes the next value of x
x(i+1) = x(i) - (f(x(i))/((f(x(i) + h) - f(x(i) - h))/((x(i)+h) - (x(i) - h))));
% function value at i+1
y(i+1) = f(x(i+1));
i=i+1;
end
0 Kommentare
Akzeptierte Antwort
Stephen23
am 22 Jan. 2020
Lets have a look at the first y value:
>> f = @(x) 4*x^2 - 3;
>> x(1) = 0.5;
>> y(1) = f(x(1))
y = -2
And now look at your while loop condition:
i = 1;
while (abs(y(i)) < 1e-4)
Do you expect 2 to be less than 0.0001 ?
Weitere Antworten (0)
Siehe auch
Kategorien
Mehr zu Loops and Conditional Statements finden Sie in Help Center und File Exchange
Produkte
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!