I am trying to reduce the step size for my inside for loop until the maximum difference between successive iterations is less than 0.1%. Is there a way for me to keep the values of y1 while reducing the step size for each run until the maxdifference?

% Initialization
h = 0.5;    %Step size
Ni = 50;    %Number of steps
x(1:Ni) = 0;
y1(1:Ni) = 0;
% Initial conditions
x(1) = 1;
y1(1) = 0;
% Modified Euler Method
for j=2:Ni
for i=2:Ni
    k1=(h)*(x(i-1)-2*x(i-1)*y1(i-1)-1)/(x(i-1)*x(i-1));
    k2=(h)*((x(i-1)+(h))-2*(x(i-1)+(h))*(y1(i-1)+k1)-1)/((x(i-1)+(h))*(x(i-1)+(h)));
    y1(i)=y1(i-1)+((k1+k2)/2);  %Approximate y value
    x(i)=x(i-1)+h; %x value
end
A(j)=diff(y1);
B(j)=max(A);
C(j)=(((B(j))-(B(j-1)))/(B(j-1)))*100;
if (C(j)>=0.1)
    h=h/2;
else
end
end
plot(x(1:11))
plot(y1(1:11))