prohibit kahan summation with mixed precision

Author: wilfonba

toolchain/mfc/case_validator.py

@@ -122,7 +122,7 @@
     "check_bubbles_lagrange": {
         "title": "Euler-Lagrange Bubble Model",
         "category": "Bubble Physics",
-        "explanation": "2D/3D only. Requires polytropic = F and thermal = 3. Not compatible with model_eqns = 3.",
+        "explanation": "2D/3D only. Requires polytropic = F and thermal = 3. Not compatible with model_eqns = 3. Kahan summation not compatible with --mixed precision.",
     },
     # Numerical Schemes
     "check_weno": {
@@ -1304,6 +1304,7 @@ def check_bubbles_lagrange(self):
         charNz = self.get("lag_params%charNz", 0)
         charWidth = self.get("lag_params%charwidth", 0)
         fd_order = self.get("fd_order", 0)
+        kahan_summation = self.get("lag_params%kahan_summation", "T") == "T"
 
         self.prohibit(n is not None and n == 0, "bubbles_lagrange accepts 2D and 3D simulations only")
         self.prohibit(file_per_process, "file_per_process must be false for bubbles_lagrange")
@@ -1316,6 +1317,7 @@ def check_bubbles_lagrange(self):
         self.prohibit(charNz <= 0 and p == 0, "lag_params%charNz must be positive for 2D bubbles_lagrange")
         self.prohibit(charWidth <= 0 and p == 0, "lag_params%charwidth must be positive for 2D bubbles_lagrange")
         self.prohibit(fd_order == 0 and vel_model > 0, "Non-zero lag_params%vel_model requires fd_order to be set")
+        self.prohibit(kahan_summation and CFG().mixed, "lag_params%kahan_summation = T is not compatible with --mixed precision")
 
     def check_continuum_damage(self):
         """Checks continuum damage model parameters (simulation)"""