Optimizations in localization

Basis/Multipole.ml

@@ -21,6 +21,7 @@ let matrix_z  t =  t.(2)
 let matrix_x2 t =  t.(3)
 let matrix_y2 t =  t.(4)
 let matrix_z2 t =  t.(5)
+let matrix_r2 t =  Mat.add t.(3) @@ Mat.add t.(4) t.(5)
 let matrix_xy t =  t.(6)
 let matrix_yz t =  t.(7)
 let matrix_zx t =  t.(8)
@@ -215,8 +216,8 @@ let of_basis basis =
       done;
     done;
   done;
-  for k=0 to 14 do
-    Mat.detri result.(k);
+  for k=0 to Array.length result - 1 do
+    Mat.detri result.(k)
   done;
   result
 

Basis/Multipole.mli

@@ -31,6 +31,9 @@ val matrix_y2 : t -> Mat.t
 val matrix_z2 : t -> Mat.t
 (** {% $$ \langle \chi_i | z^2 | \chi_j \rangle $$ %} *)
 
+val matrix_r2 : t -> Mat.t
+(** {% $$ \langle \chi_i | r^2 | \chi_j \rangle $$ %} *)
+
 val matrix_x3 : t -> Mat.t
 (** {% $$ \langle \chi_i | x^3 | \chi_j \rangle $$ %} *)