check for asin arg 1) > 1.0 and 2) 0/0

module_invariants.f90

@@ -58,8 +58,18 @@ end function third_invariant
 
 function lode_angle (J2d,J3d)
 use constants
-double precision lode_angle,J2d,J3d 
-lode_angle=asin(-1.5d0*sqrt3*J3d/J2d**(1.5d0))/3.d0
+double precision lode_angle,J2d,J3d, arg
+if ((j2d.eq.0.d0).or.(j3d.eq.0.d0)) then
+  lode_angle = 0.d0
+else
+  arg = -1.5d0*sqrt3*J3d/J2d**(1.5d0)
+  if (abs(arg).gt.1.d0) then
+    ! write(*,*) 'lode_angle; arg is ', arg, ', setting it to 1.d0'
+    arg = 1.d0
+  endif
+  lode_angle=asin(arg)/3.d0
+  ! lode_angle=asin(-1.5d0*sqrt3*J3d/J2d**(1.5d0))/3.d0
+endif
 end function lode_angle