diff --git a/Exec/Make.auto_source b/Exec/Make.auto_source
index 178e0f43e2..77b48e8fb3 100644
--- a/Exec/Make.auto_source
+++ b/Exec/Make.auto_source
@@ -69,7 +69,7 @@ CPP_PARAMETERS := $(TOP)/Source/driver/_cpp_parameters
 
 $(CASTRO_AUTO_SOURCE_DIR)/castro_params.H: $(CPP_PARAMETERS)
 	@if [ ! -d $(CASTRO_AUTO_SOURCE_DIR) ]; then mkdir -p $(CASTRO_AUTO_SOURCE_DIR); fi
-	PYTHONPATH=$(MICROPHYSICS_HOME)/util/build_scripts $(TOP)/Source/driver/parse_castro_params.py -o $(CASTRO_AUTO_SOURCE_DIR) $(CPP_PARAMETERS)
+	PYTHONPATH=$(MICROPHYSICS_HOME)/util/build_scripts $(TOP)/Source/driver/parse_castro_params.py --constexpr -o $(CASTRO_AUTO_SOURCE_DIR) $(CPP_PARAMETERS)
 
 # for debugging
 test_cxx_params: $(CASTRO_AUTO_SOURCE_DIR)/castro_params.H
diff --git a/Source/driver/Castro.cpp b/Source/driver/Castro.cpp
index f10c59b0e7..ae47a6b380 100644
--- a/Source/driver/Castro.cpp
+++ b/Source/driver/Castro.cpp
@@ -415,9 +415,9 @@ Castro::read_params ()
       }
 
     // Make sure not to call refluxing if we're not actually doing any hydro.
-    if (do_hydro == 0) {
-      do_reflux = 0;
-    }
+//    if (do_hydro == 0) {
+//      do_reflux = 0;
+//    }
 
     if (max_dt < fixed_dt)
       {
@@ -475,9 +475,9 @@ Castro::read_params ()
       }
     }
 
-    if (dgeom.IsRZ() == 1) {
-        rot_axis = 2;
-    }
+//    if (dgeom.IsRZ() == 1) {
+//        rot_axis = 2;
+//    }
 #if (AMREX_SPACEDIM == 1)
     if (do_rotation == 1) {
         std::cerr << "ERROR:Castro::Rotation not implemented in 1d\n";
@@ -2070,7 +2070,8 @@ Castro::post_timestep (int iteration_local)
         Real max_field_val = std::numeric_limits<Real>::min();
 
         for (int lev = 0; lev <= parent->finestLevel(); ++lev) {
-            auto mf = getLevel(lev).derive(castro::stopping_criterion_field, state[State_Type].curTime(), 0);
+	    std::string scf{castro::stopping_criterion_field};
+            auto mf = getLevel(lev).derive(scf, state[State_Type].curTime(), 0);
             max_field_val = std::max(max_field_val, mf->max(0));
         }
 
diff --git a/Source/driver/Castro_advance_ctu.cpp b/Source/driver/Castro_advance_ctu.cpp
index 911a2780e9..ebd22a4480 100644
--- a/Source/driver/Castro_advance_ctu.cpp
+++ b/Source/driver/Castro_advance_ctu.cpp
@@ -364,7 +364,7 @@ Castro::subcycle_advance_ctu(const Real time, const Real dt, int amr_iteration,
             // approximately compensate for that.
 
             if (in_retry) {
-                sdc_iters += 1;
+                //sdc_iters += 1;
                 amrex::Print() << "Adding an SDC iteration due to the retry." << std::endl << std::endl;
             }
 
@@ -412,7 +412,7 @@ Castro::subcycle_advance_ctu(const Real time, const Real dt, int amr_iteration,
 
         // Set sdc_iters to its original value, in case we modified it above.
 
-        sdc_iters = sdc_iters_old;
+        //sdc_iters = sdc_iters_old;
 
         // If we're allowing for retries, check for that here.
 
diff --git a/Source/driver/Castro_io.cpp b/Source/driver/Castro_io.cpp
index ea0336669e..e31697d60c 100644
--- a/Source/driver/Castro_io.cpp
+++ b/Source/driver/Castro_io.cpp
@@ -181,7 +181,8 @@ Castro::restart (Amr&     papa,
         PMFile.open(FullPathPMFile.c_str(), std::ios::in);
 
         if (PMFile.good()) {
-            PMFile >> point_mass;
+	    Real pm;
+            PMFile >> pm; // point_mass;
             PMFile.close();
         }
 
@@ -198,7 +199,8 @@ Castro::restart (Amr&     papa,
         RotationFile.open(FullPathRotationFile.c_str(), std::ios::in);
 
         if (RotationFile.is_open()) {
-            RotationFile >> castro::rotational_period;
+	    Real rp;
+            RotationFile >> rp; //castro::rotational_period;
             amrex::Print() << "  Based on the checkpoint, setting the rotational period to "
                            << std::setprecision(7) << std::fixed << castro::rotational_period << " s.\n";
             RotationFile.close();
diff --git a/Source/driver/Castro_setup.cpp b/Source/driver/Castro_setup.cpp
index 9506fdde2c..4c22e10f03 100644
--- a/Source/driver/Castro_setup.cpp
+++ b/Source/driver/Castro_setup.cpp
@@ -209,6 +209,7 @@ Castro::variableSetUp ()
 
   // set small positive values of the "small" quantities if they are
   // negative
+#if 0
   if (small_dens < 0.0_rt) {
     small_dens = 1.e-100_rt;
   }
@@ -224,13 +225,16 @@ Castro::variableSetUp ()
   if (small_ener < 0.0_rt) {
     small_ener = 1.e-100_rt;
   }
+#endif
 
   // now initialize the C++ Microphysics
 #ifdef REACTIONS
   network_init();
 #endif
 
-  eos_init(castro::small_temp, castro::small_dens);
+  Real st{castro::small_temp};
+  Real sd{castro::small_dens};
+  eos_init(st, sd);
 
 #ifdef RADIATION
   opacity_init();
@@ -240,11 +244,11 @@ Castro::variableSetUp ()
   // with the minimum permitted by the EOS, and vice versa.
 
   Real new_min_T = std::max(small_temp, EOSData::mintemp);
-  small_temp = new_min_T;
+  //small_temp = new_min_T;
   EOSData::mintemp = new_min_T;
 
   Real new_min_rho = std::max(small_dens, EOSData::mindens);
-  small_dens = new_min_rho;
+  //small_dens = new_min_rho;
   EOSData::mindens = new_min_rho;
 
   // Given small_temp and small_dens, compute small_pres
@@ -267,8 +271,8 @@ Castro::variableSetUp ()
 
   eos(eos_input_rt, eos_state);
 
-  castro::small_pres = amrex::max(castro::small_pres, eos_state.p);
-  castro::small_ener = amrex::max(castro::small_ener, eos_state.e);
+  //castro::small_pres = amrex::max(castro::small_pres, eos_state.p);
+  //castro::small_ener = amrex::max(castro::small_ener, eos_state.e);
 
   // some consistency checks on the parameters
 #ifdef REACTIONS
diff --git a/Source/driver/parse_castro_params.py b/Source/driver/parse_castro_params.py
index aedeea6624..f742be2bba 100755
--- a/Source/driver/parse_castro_params.py
+++ b/Source/driver/parse_castro_params.py
@@ -129,7 +129,7 @@ def read_param_file(infile):
 
     return params
 
-def write_headers(params, out_directory, struct_name):
+def write_headers(params, out_directory, struct_name, constexpr):
 
     # output
 
@@ -152,19 +152,23 @@ def write_headers(params, out_directory, struct_name):
         cd.write(f"#ifndef {nm.upper()}_DECLARES_H\n")
         cd.write(f"#define {nm.upper()}_DECLARES_H\n")
 
-        cd.write("\n")
-        cd.write(f"namespace {nm} {{\n")
-
-        for ifdef in ifdefs:
-            if ifdef is None:
-                for p in [q for q in params_nm if q.ifdef is None]:
-                    cd.write(p.get_declare_string())
-            else:
-                cd.write(f"#ifdef {ifdef}\n")
-                for p in [q for q in params_nm if q.ifdef == ifdef]:
-                    cd.write(p.get_declare_string())
-                cd.write("#endif\n")
-        cd.write("}\n\n")
+        if constexpr:
+            pass
+        else:
+            cd.write("\n")
+            cd.write(f"namespace {nm} {{\n")
+
+            for ifdef in ifdefs:
+                if ifdef is None:
+                    for p in [q for q in params_nm if q.ifdef is None]:
+                        cd.write(p.get_declare_string())
+                else:
+                    cd.write(f"#ifdef {ifdef}\n")
+                    for p in [q for q in params_nm if q.ifdef == ifdef]:
+                        cd.write(p.get_declare_string())
+                    cd.write("#endif\n")
+
+            cd.write("}\n\n")
         cd.write("#endif\n")
         cd.close()
 
@@ -177,19 +181,27 @@ def write_headers(params, out_directory, struct_name):
         cp.write(CWARNING)
         cp.write(f"#ifndef {nm.upper()}_PARAMS_H\n")
         cp.write(f"#define {nm.upper()}_PARAMS_H\n")
-
+        cp.write("#include <castro_limits.H>\n")
+        cp.write(f"using namespace amrex::literals;\n")
         cp.write("\n")
         cp.write(f"namespace {nm} {{\n")
 
-        for ifdef in ifdefs:
-            if ifdef is None:
-                for p in [q for q in params_nm if q.ifdef is None]:
-                    cp.write(p.get_declare_string(with_extern=True))
-            else:
-                cp.write(f"#ifdef {ifdef}\n")
-                for p in [q for q in params_nm if q.ifdef == ifdef]:
-                    cp.write(p.get_declare_string(with_extern=True))
-                cp.write("#endif\n")
+        if constexpr:
+            for p in params_nm:
+                type = p.get_cxx_decl()
+                if type == "std::string":
+                    type = "std::string_view"
+                cp.write(f"constexpr {type} {p.cpp_var_name}{{{p.default_format()}}};\n")
+        else:
+            for ifdef in ifdefs:
+                if ifdef is None:
+                    for p in [q for q in params_nm if q.ifdef is None]:
+                        cp.write(p.get_declare_string(with_extern=True))
+                else:
+                    cp.write(f"#ifdef {ifdef}\n")
+                    for p in [q for q in params_nm if q.ifdef == ifdef]:
+                        cp.write(p.get_declare_string(with_extern=True))
+                    cp.write("#endif\n")
         cp.write("}\n\n")
         cp.write("#endif\n")
         cp.close()
@@ -202,22 +214,25 @@ def write_headers(params, out_directory, struct_name):
 
         cq.write(CWARNING)
 
-        for ifdef in ifdefs:
-            if ifdef is None:
-                for p in [q for q in params_nm if q.ifdef is None]:
-                    cq.write(p.get_default_string())
-                    cq.write(p.get_query_string())
-                    cq.write(p.get_query_struct_string(struct_name=struct_name, class_name="Castro"))
-                    cq.write("\n")
-            else:
-                cq.write(f"#ifdef {ifdef}\n")
-                for p in [q for q in params_nm if q.ifdef == ifdef]:
-                    cq.write(p.get_default_string())
-                    cq.write(p.get_query_string())
-                    cq.write(p.get_query_struct_string(struct_name=struct_name, class_name="Castro"))
-                    cq.write("\n")
-                cq.write("#endif\n")
-            cq.write("\n")
+        if constexpr:
+            pass
+        else:
+            for ifdef in ifdefs:
+                if ifdef is None:
+                    for p in [q for q in params_nm if q.ifdef is None]:
+                        cq.write(p.get_default_string())
+                        cq.write(p.get_query_string())
+                        cq.write(p.get_query_struct_string(struct_name=struct_name, class_name="Castro"))
+                        cq.write("\n")
+                else:
+                    cq.write(f"#ifdef {ifdef}\n")
+                    for p in [q for q in params_nm if q.ifdef == ifdef]:
+                        cq.write(p.get_default_string())
+                        cq.write(p.get_query_string())
+                        cq.write(p.get_query_struct_string(struct_name=struct_name, class_name="Castro"))
+                        cq.write("\n")
+                    cq.write("#endif\n")
+                cq.write("\n")
         cq.close()
 
         # write the job info tests
@@ -289,13 +304,15 @@ def main():
                         help="output directory for the generated files")
     parser.add_argument("-s", type=str, default="params",
                         help="name for the name struct that will hold the parameters")
+    parser.add_argument("--constexpr", action="store_true",
+                        help="force the parameters to be constexpr without being able to query")
     parser.add_argument("input_file", type=str, nargs=1,
                         help="input file containing the list of parameters we will define")
 
     args = parser.parse_args()
 
     p = read_param_file(args.input_file[0])
-    write_headers(p, args.o, args.s)
+    write_headers(p, args.o, args.s, args.constexpr)
 
 if __name__ == "__main__":
     main()
diff --git a/Source/gravity/Castro_pointmass.cpp b/Source/gravity/Castro_pointmass.cpp
index 1bbdca2050..485a3b6886 100644
--- a/Source/gravity/Castro_pointmass.cpp
+++ b/Source/gravity/Castro_pointmass.cpp
@@ -103,7 +103,7 @@ Castro::pointmass_update(Real time, Real dt)
                                << ", to " << point_mass + mass_change_at_center << std::endl << std::endl;
             }
 
-            point_mass += mass_change_at_center;
+            //point_mass += mass_change_at_center;
 
 #ifdef _OPENMP
 #pragma omp parallel
diff --git a/Source/gravity/Gravity.cpp b/Source/gravity/Gravity.cpp
index 6665b0ef38..df6b046211 100644
--- a/Source/gravity/Gravity.cpp
+++ b/Source/gravity/Gravity.cpp
@@ -342,7 +342,7 @@ Gravity::install_level (int                   level,
 
 std::string Gravity::get_gravity_type()
 {
-  return gravity::gravity_type;
+  return std::string{gravity::gravity_type};
 }
 
 int Gravity::get_max_solve_level()
diff --git a/Source/scf/scf_relax.cpp b/Source/scf/scf_relax.cpp
index 1add2074e3..796a188a0b 100644
--- a/Source/scf/scf_relax.cpp
+++ b/Source/scf/scf_relax.cpp
@@ -327,7 +327,7 @@ Castro::do_hscf_solve()
 
         if (std::abs(scf_polar_radius - scf_equatorial_radius) / std::abs(scf_equatorial_radius) < 1.e-6) {
 
-            rotational_period = 0.0;
+            //rotational_period = 0.0;
 
         } else {
 
@@ -344,9 +344,9 @@ Castro::do_hscf_solve()
             // Let's also be sure not to let the period
             // change by too much in a single iteration.
 
-            rotational_period = amrex::min(1.1_rt * rotational_period,
-                                           amrex::max(0.9_rt * rotational_period,
-                                                      2.0_rt * M_PI / omega));
+            //rotational_period = amrex::min(1.1_rt * rotational_period,
+            //                               amrex::max(0.9_rt * rotational_period,
+            //                                          2.0_rt * M_PI / omega));
 
         }