diff --git a/org/qmckl_jastrow.org b/org/qmckl_jastrow.org
index a713a5e..0f63118 100644
--- a/org/qmckl_jastrow.org
+++ b/org/qmckl_jastrow.org
@@ -1642,7 +1642,7 @@ integer function qmckl_compute_factor_ee_f(context, walk_num, elec_num, up_num,
 end function qmckl_compute_factor_ee_f
     #+end_src
 
-#+begin_src c :tangle (eval h_func) :comments org
+#+begin_src c   :comments org :tangle (eval c) :noweb yes
     qmckl_exit_code qmckl_compute_factor_ee (
 	  const qmckl_context context,
 	  const int64_t walk_num,
@@ -1654,8 +1654,56 @@ end function qmckl_compute_factor_ee_f
 	  const double* asymp_jasb,
 	  double* const factor_ee ) {
 
+  int64_t ipar; // can we use a smaller integer?
+  double pow_ser, x, 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 (bord_num <= 0) {
+     return QMCKL_INVALID_ARG_4;
+  } 
+
+  for (int nw = 0; nw < walk_num; ++nw) {
+    factor_ee[nw] = 0.0; // put init array here.
+    for (int j = 0; j < elec_num; ++j ) {
+      for (int i = 0; i < j; ++i) {
+        x = ee_distance_rescaled[nw][i][j];
+        power_ser = 0.0;
+        spin_fact = 1.0;
+        ipar = 0; // index of asymp_jasb 
+
+        for (int p = 1; p < bord_num; ++p) { 
+          x = x * ee_distance_rescaled[nw][i][j];
+          power_ser = power_ser + bord_vector[p + 1] * x;
+        }
+
+        if(j <= up_num || i > up_num) {
+          spin_fact = 0.5;
+          ipar = 1;
+        }
+        
+        factor_ee[nw] = factor_ee[nw] + spin_fact * bord_vector[0]  * \
+                                ee_distance_rescaled[nw][i][j] /      \
+                                (1.0 + bord_vector[1] *               \
+                                ee_distance_rescaled[nw][i][j])       \
+                               -asymp_jasb[ipar] + power_ser;
+
+      }
     }
+  }
+
+  return QMCKL_SUCCESS;
+}
 #+end_src
 
     #+CALL: generate_c_header(table=qmckl_factor_ee_args,rettyp=get_value("CRetType"),fname=get_value("Name"))
@@ -1677,47 +1725,6 @@ end function qmckl_compute_factor_ee_f
 
     #+CALL: generate_c_interface(table=qmckl_factor_ee_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_ee &
-	(context, &
-		 walk_num, &
-		 elec_num, &
-		 up_num, &
-		 bord_num, &
-		 bord_vector, &
-		 ee_distance_rescaled, &
-		 asymp_jasb, &
-		 factor_ee) &
-	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 :: up_num
-      integer (c_int64_t) , intent(in)  , value :: bord_num
-      real    (c_double ) , intent(in)          :: bord_vector(bord_num + 1)
-      real    (c_double ) , intent(in)          :: ee_distance_rescaled(elec_num,elec_num,walk_num)
-      real    (c_double ) , intent(in)          :: asymp_jasb(2)
-      real    (c_double ) , intent(out)         :: factor_ee(walk_num)
-
-      integer(c_int32_t), external :: qmckl_compute_factor_ee_f
-      info = qmckl_compute_factor_ee_f &
-	     (context, &
-		 walk_num, &
-		 elec_num, &
-		 up_num, &
-		 bord_num, &
-		 bord_vector, &
-		 ee_distance_rescaled, &
-		 asymp_jasb, &
-		 factor_ee)
-
-    end function qmckl_compute_factor_ee
-    #+end_src
 
 *** Test
     #+begin_src python :results output :exports none :noweb yes