Fix three CodeRabbit-flagged bugs in THINC compression

- m_weno.fpp: add missing 'use m_nvtx' for nvtxStartRange/nvtxEndRange calls
- m_thinc.fpp: clamp atanh argument in f_log_cosh_diff to avoid Inf/NaN when
  tanh saturates to ±1 on sharp interfaces
- m_checker.fpp: prohibit muscl_order==1 with int_comp>0 (uninitialized workspace)

Author: sbryngelson

src/simulation/m_checker.fpp

@@ -80,6 +80,8 @@ contains
         @:PROHIBIT(p + 1 < min(1, p)*num_stcls_min*muscl_order, &
                    & "For 3D simulation, p must be greater than or equal to (num_stcls_min*muscl_order - 1), whose value is " &
                    & // trim(numStr))
+        @:PROHIBIT(muscl_order == 1 .and. int_comp > 0, &
+                   & "int_comp requires muscl_order >= 2 (muscl_order=1 leaves the reconstruction workspace uninitialised)")
 
     end subroutine s_check_inputs_muscl
 

src/simulation/m_thinc.fpp

@@ -62,9 +62,10 @@ contains
 
         $:GPU_ROUTINE(parallelism='[seq]')
         real(wp), intent(in) :: a, h
-        real(wp)             :: res
+        real(wp)             :: res, t
 
-        res = 2._wp*atanh(tanh(a)*tanh(h))
+        t = tanh(a)*tanh(h)
+        res = 2._wp*atanh(sign(min(abs(t), 1._wp - epsilon(1._wp)), t))
 
     end function f_log_cosh_diff
 

src/simulation/m_weno.fpp

@@ -14,6 +14,7 @@ module m_weno
 
     use m_mpi_proxy
     use m_thinc, only: s_thinc_compression
+    use m_nvtx
 
     private; public :: s_initialize_weno_module, s_initialize_weno, s_finalize_weno_module, s_weno