From add68968b679244ab4f346785ac7b0130221c779 Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Sat, 16 Feb 2019 11:05:38 +0100
Subject: [PATCH] Double excitation operators

---
 CI/Spindeterminant.ml | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/CI/Spindeterminant.ml b/CI/Spindeterminant.ml
index c12d774..fc53974 100644
--- a/CI/Spindeterminant.ml
+++ b/CI/Spindeterminant.ml
@@ -63,8 +63,16 @@ let annihilation h = function
 let single_excitation_reference h p spindet = 
       creation p @@ annihilation h @@ spindet
 
-let single_excitation p q = 
-  single_excitation_reference p q
+let single_excitation h p = 
+  single_excitation_reference h p
+
+
+let double_excitation_reference h' p' h p spindet = 
+      creation p' @@ creation p @@ annihilation h @@ annihilation h' @@ spindet
+
+let double_excitation h' p' h p =
+  double_excitation_reference h' p' h p
+
 
 let of_list l = 
   List.rev l
@@ -162,8 +170,17 @@ let test_case () =
     let det = of_list l_a in
     let l_b = [ 1 ; 7 ; 3 ; 5 ] in
     let det2 = of_list l_b in
-    Alcotest.(check bool) "single 1" true (single_excitation 2 7 det = det2);
-    Alcotest.(check bool) "single 1" true (single_excitation 4 7 det |> is_none);
+    Alcotest.(check bool) "single 1" true (single_excitation_reference 2 7 det = det2);
+    Alcotest.(check bool) "single 2" true (single_excitation 2 7 det = single_excitation_reference 2 7 det);
+    Alcotest.(check bool) "single 3" true (single_excitation_reference 4 7 det |> is_none);
+    Alcotest.(check bool) "single 4" true (single_excitation 4 7 det |> is_none);
+
+    let l_c = [ 1 ; 7 ; 6 ; 5 ] in
+    let det3 = of_list l_c in
+    Alcotest.(check bool) "double 1" true (double_excitation_reference 2 7 3 6 det = det3);
+    Alcotest.(check bool) "double 2" true (double_excitation 2 7 3 6 det = double_excitation_reference 2 7 3 6 det);
+    Alcotest.(check bool) "double 3" true (double_excitation_reference 4 7 3 6 det |> is_none);
+    Alcotest.(check bool) "double 4" true (double_excitation 4 7 3 6 det |> is_none);
   in
   [
     "Creation", `Quick, test_creation;