Floating point error

Sohail Ahmed

I am doing solution of a 2D, convergent-divergent nozzle flow problem. While iterating for the solution it gives a message of "floating point error: invalid number". In the convergence plot, it does not show energy line. And the velocities (x,y)and continuity lines very much deviate from their convergence criteria. Please help me out in understanding this " floating point error"!