From 8cc2c6a24bb7647bf99e3736260249fa746c945b Mon Sep 17 00:00:00 2001
From: Anthony Scemama <scemama@irsamc.ups-tlse.fr>
Date: Mon, 2 May 2016 10:52:29 +0200
Subject: [PATCH] Implemented ZV DMC

---
 src/PROPERTIES/properties_energy.irp.f | 8 ++++++++
 src/SAMPLING/dmc_step.irp.f            | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/src/PROPERTIES/properties_energy.irp.f b/src/PROPERTIES/properties_energy.irp.f
index d21f973..e6d40e9 100644
--- a/src/PROPERTIES/properties_energy.irp.f
+++ b/src/PROPERTIES/properties_energy.irp.f
@@ -248,5 +248,13 @@ BEGIN_PROVIDER  [ double precision, E_loc ]
 END_PROVIDER
 
 
+BEGIN_PROVIDER [ double precision, E_loc_zv ]
+ implicit none
+ BEGIN_DOC
+ ! Zero-variance parameter on E_loc
+ END_DOC
+ E_loc_zv = E_ref - E_loc 
+END_PROVIDER
+
 
 
diff --git a/src/SAMPLING/dmc_step.irp.f b/src/SAMPLING/dmc_step.irp.f
index 2764609..0694a68 100644
--- a/src/SAMPLING/dmc_step.irp.f
+++ b/src/SAMPLING/dmc_step.irp.f
@@ -150,6 +150,11 @@ END_SHELL
    psi_value_save(i_walk) = psi_value
    E_loc_save(i_walk) = E_loc
 
+   if (calc_E_loc_zv) then
+     E_loc_zv = (E_ref - E_loc)/dmc_weight(i_walk)
+     TOUCH E_loc_zv
+   endif
+
 BEGIN_SHELL [ /usr/bin/python ]
 from properties import *
 t = """