Positive potential derivative

include/primordial.h

@@ -69,6 +69,12 @@ enum inflation_module_behavior {
                                 analytical
 };
 
+/** enum specifying potential derivative dV/dphi sign */
+
+enum potential_derivative_sign {
+                                positive,
+                                negative
+};
 /**
  * Structure containing everything about primordial spectra that other modules need to know.
  *
@@ -181,6 +187,9 @@ struct primordial {
   enum phi_pivot_methods phi_pivot_method; /**< flag for method used to define and find the pivot scale */
   double phi_pivot_target; /**< For each of the above methods, critical value to be reached between pivot and end of inflation (N_star, [aH]ratio, etc.) */
 
+  /* parameter describing potential derivative dV/dphi sign */
+  enum potential_derivative_sign potential_derivative;
+
   /* behavior of the inflation module */
   enum inflation_module_behavior behavior; /**< Specifies if the inflation module computes the primordial spectrum numerically (default) or analytically*/
 

source/input.c

@@ -4195,6 +4195,24 @@ int input_read_parameters_primordial(struct file_content * pfc,
 
   else if ((ppm->primordial_spec_type == inflation_V) || (ppm->primordial_spec_type == inflation_H)) {
 
+
+    /* Sign of derivative of potential, dV/dphi */
+    class_call(parser_read_string(pfc,"potential_derivative",&string1,&flag1,errmsg),
+               errmsg,
+               errmsg);
+    /* Complete set of parameters */
+    if (flag1 == _TRUE_) {
+      if (strcmp(string1,"positive") == 0){
+        ppm->potential_derivative = positive;
+      }
+      else if (strcmp(string1,"negative") == 0){
+        ppm->potential_derivative = negative;
+      }
+      else{
+        class_stop(errmsg,"You specified 'potential_derivative' as '%s'. It has to be one of {'positive','negative'}.",string1);
+      }
+    }
+
     /** 1.c) For type 'inflation_V' */
     if (ppm->primordial_spec_type == inflation_V) {
 
@@ -4344,6 +4362,22 @@ int input_read_parameters_primordial(struct file_content * pfc,
         class_stop(errmsg,"You specified 'full_potential' as '%s'. It has to be one of {'polynomial','higgs_inflation'}.",string1);
       }
     }
+     /* Sign of derivative of potential, dV/dphi */
+    class_call(parser_read_string(pfc,"potential_derivative",&string1,&flag1,errmsg),
+               errmsg,
+               errmsg);
+    /* Complete set of parameters */
+    if (flag1 == _TRUE_) {
+      if (strcmp(string1,"positive") == 0){
+        ppm->potential_derivative = positive;
+      }
+      else if (strcmp(string1,"negative") == 0){
+        ppm->potential = negative;
+      }
+      else{
+        class_stop(errmsg,"You specified 'potential_derivative' as '%s'. It has to be one of {'positive','negative'}.",string1);
+      }
+    }
 
     /** 1.e.3) Parameters of the potential */
     /* Read */
@@ -5940,6 +5974,8 @@ int input_default_params(struct background *pba,
   ppm->phi_end=0.;
   /** 1.e.2) Shape of the potential */
   ppm->potential=polynomial;
+   /* Sign of derivative of potential, dV/dphi */
+  ppm->potential_derivative=negative;
   /** 1.e.4) Increase of scale factor or (aH) between Hubble crossing at pivot
       scale and end of inflation */
   ppm->phi_pivot_method = N_star;