After looking through your code, it seems that the issue is due to the last "while" loop in Line 352, as pointed out in your query. The issue is that for the breaking condition of the "while" loop to be met, the value of "Le(q)" must be greater than "Lrange(2)". However, after the first few iterations, the value of "Le(q)" and "q" are not updated as the following "if" condition in your code is not satisfied, since the value of "gres_v" and "H" is above the set tolerance:
if gres_v<tol && gres_T<tol || H<2*Hmin
v(q+1)=v_II;
T(q+1)=T_II;
if Lq+H>br1
Le(q+1)=Lrange(2);
else
Le(q+1)=Lq+H;
end
P(q+1)=f*omega*(1-(v_II/V_gr)^2)/(s*(L_1+Le(q+1)));
q=q+1;
Lq=Le(q);
end
As a result, the loop keeps running indefinitely, and the program never completes. To resolve this, you may look into the above snippet from your code (Line 394) to address the update issue for "Le(q)".
Additionally, you may refer to following File Exchange submissions on "Runge-Kutta-Fehlberg" which may be helpful:
