diff --git a/org/qmckl_jastrow.org b/org/qmckl_jastrow.org
index c46fe63..a177d91 100644
--- a/org/qmckl_jastrow.org
+++ b/org/qmckl_jastrow.org
@@ -2442,6 +2442,74 @@ integer function qmckl_compute_factor_en_f(context, walk_num, elec_num, nucl_num
 
 end function qmckl_compute_factor_en_f
     #+end_src
+    
+
+    #+begin_src c :comments org :tangle (eval c) :noweb yes
+qmckl_exit_code qmckl_compute_factor_en (
+	  const qmckl_context context,
+	  const int64_t walk_num,
+	  const int64_t elec_num,
+	  const int64_t nucl_num,
+	  const int64_t type_nucl_num,
+	  const int64_t* type_nucl_vector,
+	  const int64_t aord_num,
+	  const double* aord_vector,
+	  const double* en_distance_rescaled,
+	  double* const factor_en ) {
+
+
+  int     ipar;
+  double  x, x1, spin_fact, power_ser;
+
+
+  if (context == QMCKL_NULL_CONTEXT) {
+     return QMCKL_INVALID_CONTEXT;
+  }
+
+  if (walk_num <= 0) {
+     return QMCKL_INVALID_ARG_2;
+  }
+
+  if (elec_num <= 0) {
+     return QMCKL_INVALID_ARG_3;
+  }
+
+  if (nucl_num <= 0) {
+     return QMCKL_INVALID_ARG_4;
+  }
+
+  if (aord_num <= 0) {
+     return QMCKL_INVALID_ARG_7;
+  }
+
+
+  for (int nw = 0; nw < walk_num; ++nw ) {
+    // init array
+    factor_en[nw] = 0.0;
+    for (int a = 0; a < nucl_num; ++a ) {
+      for (int i = 0; i < elec_num; ++i ) {
+        // x = ee_distance_rescaled[j * (walk_num * elec_num) + i * (walk_num) + nw];
+        x = en_distance_rescaled[i * (walk_num * nucl_num) + a * (walk_num) + nw];
+        x1 = x;
+        power_ser = 0.0;
+
+        for (int p = 2; p < aord_num+1; ++p) { 
+          x = x * x1;
+          power_ser = power_ser + aord_vector[(p+1)-1 + (type_nucl_vector[a]-1) * aord_num] * x;
+        }
+
+        factor_en[nw] = factor_en[nw] + aord_vector[0 + (type_nucl_vector[a]-1)*aord_num] * x1 / \
+                        (1.0 + aord_vector[1 + (type_nucl_vector[a]-1) * aord_num] * x1) + \
+                        power_ser;
+
+      }
+    }
+  }
+
+  return QMCKL_SUCCESS;
+}
+    #+end_src
+
 
     #+CALL: generate_c_header(table=qmckl_factor_en_args,rettyp=get_value("CRetType"),fname=get_value("Name"))
 
@@ -2461,53 +2529,6 @@ end function qmckl_compute_factor_en_f
     #+end_src
 
 
-    #+CALL: generate_c_interface(table=qmckl_factor_en_args,rettyp=get_value("CRetType"),fname=get_value("Name"))
-
-    #+RESULTS:
-    #+begin_src f90 :tangle (eval f) :comments org :exports none
-    integer(c_int32_t) function qmckl_compute_factor_en &
-	(context, &
-		 walk_num, &
-		 elec_num, &
-		 nucl_num, &
-		 type_nucl_num, &
-		 type_nucl_vector, &
-		 aord_num, &
-		 aord_vector, &
-		 en_distance_rescaled, &
-		 factor_en) &
-	bind(C) result(info)
-
-      use, intrinsic :: iso_c_binding
-      implicit none
-
-      integer (c_int64_t) , intent(in)  , value :: context
-      integer (c_int64_t) , intent(in)  , value :: walk_num
-      integer (c_int64_t) , intent(in)  , value :: elec_num
-      integer (c_int64_t) , intent(in)  , value :: nucl_num
-      integer (c_int64_t) , intent(in)  , value :: type_nucl_num
-      integer (c_int64_t) , intent(in)          :: type_nucl_vector(nucl_num)
-      integer (c_int64_t) , intent(in)  , value :: aord_num
-      real    (c_double ) , intent(in)          :: aord_vector(aord_num + 1, type_nucl_num)
-      real    (c_double ) , intent(in)          :: en_distance_rescaled(elec_num, nucl_num, walk_num)
-      real    (c_double ) , intent(out)         :: factor_en(walk_num)
-
-      integer(c_int32_t), external :: qmckl_compute_factor_en_f
-      info = qmckl_compute_factor_en_f &
-	     (context, &
-		 walk_num, &
-		 elec_num, &
-		 nucl_num, &
-		 type_nucl_num, &
-		 type_nucl_vector, &
-		 aord_num, &
-		 aord_vector, &
-		 en_distance_rescaled, &
-		 factor_en)
-
-    end function qmckl_compute_factor_en
-    #+end_src
-
 *** Test
     #+begin_src python :results output :exports none :noweb yes
 import numpy as np