Just wondering if there is an update regarding this issue, I too have been having similar problems???

Hi,

The simple pendulum case below worked in version 1.8 but crashes in 1.9. Is this is a new bug or am I missing something???

class pendulum
  constant Real PI = 3.14159;
  parameter Real m = 1,g = 9.81,L = 0.5;
  Real F;
  output Real x(start = 0.5),y(start = 0);
  output Real vx,vy;
equation
  m * der(vx) = -x / L * F;
  m * der(vy) = -y / L * F - m * g;
  der(x) = vx;
  der(y) = vy;
  x ^ 2 + y ^ 2 = L ^ 2;
end pendulum;