infinity recursion with in the program

I get this message while trying to generate a resule using the following function " out of memory. The likely cause is an infinite recursion within the program.

Error in newplot( line 53)

fig goobjects(0);"

f= @(x) 1-sin(x);

fixpointgraf(f,0,pi,-1,1)

testpoints = linspace(.45,.55)

punktStabil(f,testpoints)

fixIter(f,.5,100)

function stabil = punktStabil(f,testpoints)

h=1e-7;

Delta=(f(testpoints+(h))-f(testpoints))/(h);

stabil= false;

for i=1:1:length(Delta)-1

if abs(Delta(i))>1

stabil= true;

end

end

if punktStabil(f,Delta)

disp('punkten nära 1.6 är stabil för f')

else

disp('punkten nära 1.6 äe ej stabil för f1.')

end

end

function iter_lst = fixIter(f,x0,N)

iter_lst = zeros(N,1); % skapa en lista med 100 nollor vi kan fylla.

iter_lst(1) = x0;

for k=1:1:N

iter_lst(1i ) = f(iter_lst(1i-1));

end

figure()

scatter(1:1:N,iter_lst)

end

Answer 1

[John D'Errico]

What do you expect? Look carefully at your code. I've extracted the only lines that matter below.

function stabil = punktStabil(f,testpoints)
  ... (stuff)
      
if punktStabil(f,Delta)
  ... (stuff)

We see a function called punktStabil. Now, suppose you call this code as a function. One of the first things the code does is call the function punktStabil. And worse, there is no way for the code to terminate before it reaches the recursive call to punktStabil.

Now we should count how many times punktStabil gets called. That is,

punktStabil calls punktStabil which calls punktStabil which calls punktStabil which calls punktStabil...

The recursive calls never terminate. Your function calls itself infinitely many times. Eventually MATLAB runs out of memory.

Now, go back and read the message you got.

out of memory. The likely cause is an infinite recursion within the program.

[Hailat Berhane Ghebremdhin]

even though I try to take fix fixpunkt function like the following, I still get the same problem:

f= @(x) 1-sin(x);

fixpointgraf(f,0,pi,-1,1)

testpoints = linspace(.45,.55);

punktStabil(f,testpoints)

fixIter(f,.5,100)

function fixpointgraf(f,a,b,c,d)

x= linspace(a,b);

plot(x,f(x))

hold on

plot(x,x )

end

function stabil = punktStabil(f,testpoints)

h=1e-7;

Delta(f(testpoints+(h))-f(testpoints))/(h);

for i=1:1:length(Delta)-1

if abs(Delta(i))>1

stabil= true;

end

end

if found

disp('punkten nära 1.6 är stabil för f')

else

disp('punkten nära 1.6 äe ej stabil för f1.')

end

end

function iter_lst = fixIter(f,x0,N)

iter_lst = zeros(N,1); % skapa en lista med 100 nollor vi kan fylla.

iter_lst(1) = x0;

for k=2:1:N

iter_lst(1i ) = f(iter_lst(1i-1));

end

figure()

scatter(1:1:N,iter_lst)

end

[John D'Errico]

f= @(x) 1-sin(x);
fixpointgraf(f,0,pi,-1,1)

testpoints = linspace(.45,.55);
punktStabil(f,testpoints)

Unrecognized function or variable 'Delta'.

Error in solution>punktStabil (line 14)
Delta(f(testpoints+(h))-f(testpoints))/(h);

fixIter(f,.5,100)
function fixpointgraf(f,a,b,c,d)
x= linspace(a,b);
plot(x,f(x))
hold on
plot(x,x )
end
function stabil = punktStabil(f,testpoints)
h=1e-7;
Delta(f(testpoints+(h))-f(testpoints))/(h); 
for i=1:1:length(Delta)-1
    if abs(Delta(i))>1
        stabil= true;
    end
end
if found
    disp('punkten nära 1.6 är stabil för f')
else 
    disp('punkten nära 1.6 äe ej stabil för f1.')
end
end 
function iter_lst = fixIter(f,x0,N)
iter_lst = zeros(N,1); % skapa en lista med 100 nollor vi kan fylla.
iter_lst(1) = x0;
for k=2:1:N
    iter_lst(1i ) = f(iter_lst(1i-1));
end
figure()
scatter(1:1:N,iter_lst)
end

Sigh. Of course there is a problem. Delta is now undefined.