OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Compile error no executable created › Reply To: Compile error no executable created August 19, 2020 at 10:51 am #5100 ThomasBParticipant Hi Robin, I have the same problem : M_PI not defined 🙁 I am using 1.3r1 (with cygwin64 on windows10) where do i have to add the line #include <math.h> ? thank you BR Thomas