From b269cd74033fc0b646daf349e09d4d9a0e2dd42f Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Sun, 5 Mar 2023 23:38:34 +0100
Subject: [PATCH] Documentation

---
 org/qmckl_jastrow.org | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/org/qmckl_jastrow.org b/org/qmckl_jastrow.org
index 86345b9..9217bd9 100644
--- a/org/qmckl_jastrow.org
+++ b/org/qmckl_jastrow.org
@@ -2065,7 +2065,9 @@ assert(fabs(asymp_jasb[1]-0.31567342786262853) < 1.e-12);
   component and the electron-electron rescaled distances ~ee_distance_rescaled~.
 
   \[
-    f_\text{ee} = \sum_{i,j<i} \left[ \frac{\delta_{ij}^{\uparrow\downarrow} B_0\, C_{ij}}{1 - B_1\, C_{ij}} + \sum^{n_\text{ord}}_{k} B_k\, C_{ij}^k - {J_{\text{ee}}^{\infty}}_{ij} \right] 
+    f_\text{ee} = \sum_{i,j<i} \left[
+    \frac{\delta_{ij}^{\uparrow\downarrow} B_0\, C_{ij}}{1 - B_1\,
+    C_{ij}} + \sum_{k=2}^{n_\text{ord}} B_k\, C_{ij}^k - {J_{\text{ee}}^{\infty}}_{ij} \right] 
   \]
 
   $\delta$ is the spin factor, $B$ is the vector of $b$ parameters,
@@ -2521,13 +2523,17 @@ assert(fabs(factor_ee[0]+4.282760865958113) < 1.e-12);
 
 ** Electron-electron component derivative \(f'_{ee}\)
 
-  Calculate the derivative of the ~factor_ee~ using the ~ee_distance_rescaled~ and
+  The derivative of ~factor_ee~ is computed using the ~ee_distance_rescaled~ and
   the electron-electron rescaled distances derivatives ~ee_distance_rescaled_deriv_e~.
   There are four components, the gradient which has 3 components in the \(x, y, z\)
   directions and the laplacian as the last component.
 
- # TODO: Add equation
+  \[ \nabla_i f_\text{ee} = \frac{1}{2}\sum_{j}
+\left[\frac{\delta_{ij}^{\uparrow\downarrow} B_0\, \nabla_i
+C_{ij}}{(1 - B_1\, C_{ij})^2} + \sum^{n_\text{ord}}_{k=2}
+B_k\, k\, C_{ij}^{k-1} \nabla C_{ij} \right] \]
 
+# TODO Laplacian
 *** Get
     #+begin_src c :comments org :tangle (eval h_func) :noweb yes
 qmckl_exit_code
@@ -2740,8 +2746,8 @@ integer function qmckl_compute_factor_ee_deriv_e_doc_f( &
         dx(3) = ee_distance_rescaled_deriv_e(3, i, j, nw)
         dx(4) = ee_distance_rescaled_deriv_e(4, i, j, nw)
 
-        if((i .LE. up_num .AND. j .LE. up_num ) .OR.  &
-           (i .GT. up_num .AND. j .GT. up_num)) then
+        if((i <= up_num && j <= up_num ) .OR.  &
+           (i >  up_num && j >  up_num)) then
           spin_fact = 0.5d0
         endif
 
@@ -2761,8 +2767,8 @@ integer function qmckl_compute_factor_ee_deriv_e_doc_f( &
 
           lap3 = lap3 - 2.0d0 * b_vector(2) * dx(ii) * dx(ii)
 
-          factor_ee_deriv_e( j, ii, nw) = factor_ee_deriv_e( j, ii, nw) + spin_fact * b_vector(1)  * &
-                                dx(ii) * invden2 + pow_ser_g(ii)
+          factor_ee_deriv_e( j, ii, nw) = factor_ee_deriv_e( j, ii, nw)  &
+               + spin_fact * b_vector(1) * dx(ii) * invden2 + pow_ser_g(ii)
         end do
 
         ii = 4