refactor: When atomic total forces are invalid, ensure colvar total force is zero after collection

Author: giacomofiorin

src/colvar.cpp

@@ -1407,10 +1407,6 @@ int colvar::calc()
     error_code |= update_cvc_flags();
     if (error_code != COLVARS_OK) return error_code;
     error_code |= calc_cvcs();
-    if (!cvm::main()->proxy->total_forces_valid()) {
-      // Zero out the colvar total force when atomic total forces are not available
-      reset_total_force();
-    }
     if (error_code != COLVARS_OK) return error_code;
     error_code |= collect_cvc_data();
   }
@@ -1435,9 +1431,6 @@ int colvar::calc_cvcs(int first_cvc, size_t num_cvcs)
     // Use Jacobian derivative computed at previous timestep and the total forces from the same
     // step, collected just now from the engine
     error_code |= calc_cvc_total_force(first_cvc, num_cvcs);
-  } else {
-    // Zero out the colvar total force when atomic total forces are not available
-    reset_total_force();
   }
   // atom coordinates are updated by the next line
   error_code |= calc_cvc_values(first_cvc, num_cvcs);
@@ -1476,6 +1469,11 @@ int colvar::collect_cvc_data()
   }
   error_code |= calc_colvar_properties();
 
+  if (!cvm::main()->proxy->total_forces_valid()) {
+    // Zero out the colvar total force when atomic total forces are not available
+    reset_total_force();
+  }
+
   if (cvm::debug())
     cvm::log("Done calculating colvar \""+this->name+"\"'s properties.\n");
 

src/colvar_gpu_calc.cpp

@@ -23,16 +23,16 @@ int colvarmodule_gpu_calc::cvc_calc_total_force(
   colvarmodule* colvar_module,
   bool use_current_step) {
   int error_code = COLVARS_OK;
+  const bool total_force_valid = colvar_module->proxy ? colvar_module->proxy->total_forces_valid() : false;
+  if (!total_force_valid) {
+    return error_code;
+  }
 #if defined (COLVARS_NVTX_PROFILING)
   cvc_calc_total_force_prof.start();
 #endif // defined (COLVARS_NVTX_PROFILING)
-  const bool total_force_valid = colvar_module->proxy ? colvar_module->proxy->total_forces_valid() : false;
   for (auto cvi = colvars.begin(); cvi != colvars.end(); cvi++) {
     // Calculate CVC total force
     if (!(*cvi)->is_enabled(colvardeps::f_cv_total_force_calc)) continue;
-    if (!total_force_valid) {
-      (*cvi)->reset_total_force();
-    }
     const bool do_total_force =
       use_current_step ?
        (*cvi)->is_enabled(colvardeps::f_cv_total_force_current_step) :
@@ -43,8 +43,7 @@ int colvarmodule_gpu_calc::cvc_calc_total_force(
       }
       const auto all_cvcs = (*cvi)->get_cvcs();
       for (auto cvc = all_cvcs.begin(); cvc != all_cvcs.end(); ++cvc) {
-        if (!(*cvc)->is_enabled(colvardeps::f_cvc_active)) continue;
-        if ((*cvc)->is_enabled(colvardeps::f_cvc_active) && total_force_valid) {
+        if ((*cvc)->is_enabled(colvardeps::f_cvc_active)) {
           (*cvc)->calc_force_invgrads();
         }
       }
@@ -361,11 +360,16 @@ int colvarmodule_gpu_calc::cvc_calc_Jacobian_derivative(const std::vector<colvar
 
 int colvarmodule_gpu_calc::cv_collect_cvc_data(const std::vector<colvar*>& colvars, colvarmodule* colvar_module) {
   int error_code = COLVARS_OK;
+  const bool total_force_valid = colvar_module->proxy ? colvar_module->proxy->total_forces_valid() : false;
 #if defined (COLVARS_NVTX_PROFILING)
   cv_collect_cvc_data_prof.start();
 #endif // defined (COLVARS_NVTX_PROFILING)
   for (auto cvi = colvars.begin(); cvi != colvars.end(); cvi++) {
-    error_code |= (*cvi)->collect_cvc_data();
+    if (total_force_valid) {
+      error_code |= (*cvi)->collect_cvc_data();
+    } else {
+      (*cvi)->reset_total_force();
+    }
     if (colvar_module->get_error()) {
       return COLVARS_ERROR;
     }