From b0413b1d139550cd7de1742059716f5b16ccd0ae Mon Sep 17 00:00:00 2001
From: Pierre-Francois Loos <pierrefrancois.loos@gmail.com>
Date: Wed, 24 Nov 2021 11:53:25 +0100
Subject: [PATCH] clean up CC-S51 functional

---
 ..._lda_exchange_derivative_discontinuity.f90 |  7 ++--
 src/eDFT/UCC_lda_exchange_energy.f90          | 36 +++----------------
 .../UCC_lda_exchange_individual_energy.f90    |  7 ++--
 src/eDFT/UCC_lda_exchange_potential.f90       | 31 ++--------------
 4 files changed, 14 insertions(+), 67 deletions(-)

diff --git a/src/eDFT/UCC_lda_exchange_derivative_discontinuity.f90 b/src/eDFT/UCC_lda_exchange_derivative_discontinuity.f90
index c8afe3c..a8b0d1a 100644
--- a/src/eDFT/UCC_lda_exchange_derivative_discontinuity.f90
+++ b/src/eDFT/UCC_lda_exchange_derivative_discontinuity.f90
@@ -44,14 +44,13 @@ subroutine UCC_lda_exchange_derivative_discontinuity(nEns,wEns,nCC,aCC,nGrid,wei
   allocate(dExdw(nEns))
 
 
-! Parameters for N -> N-1
+! Parameters for first state
 
   a1 = aCC(1,1)
   b1 = aCC(2,1)
   c1 = aCC(3,1)
 
-
-! Parameters for N -> N+1
+! Parameters for second state
 
   a2 = aCC(1,2)
   b2 = aCC(2,2)
@@ -60,6 +59,7 @@ subroutine UCC_lda_exchange_derivative_discontinuity(nEns,wEns,nCC,aCC,nGrid,wei
   w1 = wEns(2)
   w2 = wEns(3)
 
+! Defining enhancements factor for weight-dependent functionals
 
   if (doNcentered) then
   
@@ -88,7 +88,6 @@ subroutine UCC_lda_exchange_derivative_discontinuity(nEns,wEns,nCC,aCC,nGrid,wei
 
   else
 
-
     select case (Cx_choice)
 
       case(1)
diff --git a/src/eDFT/UCC_lda_exchange_energy.f90 b/src/eDFT/UCC_lda_exchange_energy.f90
index 392a5e4..5bc917d 100644
--- a/src/eDFT/UCC_lda_exchange_energy.f90
+++ b/src/eDFT/UCC_lda_exchange_energy.f90
@@ -30,44 +30,19 @@ subroutine UCC_lda_exchange_energy(nEns,wEns,nCC,aCC,nGrid,weight,rho,Cx_choice,
 
   double precision              :: Ex
 
-! Single excitation parameter
-
-!  a1 = 0.0d0
-!  b1 = 0.0d0
-!  c1 = 0.0d0
-
-! Parameters for H2 at equilibrium
-
-! a2 = +0.5751782560799208d0
-! b2 = -0.021108186591137282d0
-! c2 = -0.36718902716347124d0
-
-! Parameters for stretch H2
-
-!  a2 = + 0.01922622507087411d0
-!  b2 = - 0.01799647558018601d0
-!  c2 = - 0.022945430666782573d0
-
-! Parameters for He
-
-! a2 = 1.9125735895875828d0
-! b2 = 2.715266992840757d0
-! c2 = 2.1634223380633086d0
-
-! Parameters for He N -> N-1
+! Parameters for first state
 
   a1 = aCC(1,1)
   b1 = aCC(2,1)
   c1 = aCC(3,1)
 
-! Parameters for He N -> N+1
+! Parameters for second state
 
   a2 = aCC(1,2)
   b2 = aCC(2,2)
   c2 = aCC(3,2)
 
-! Fx1 for states N and N-1
-! Fx2 for states N and N+1
+! Defining enhancements factor for weight-dependent functionals
 
   if(doNcentered) then 
     
@@ -79,7 +54,6 @@ subroutine UCC_lda_exchange_energy(nEns,wEns,nCC,aCC,nGrid,weight,rho,Cx_choice,
 
   else  
 
-
     w1 = wEns(2)
     Fx1 = 1d0 - w1*(1d0 - w1)*(a1 + b1*(w1 - 0.5d0) + c1*(w1 - 0.5d0)**2)
 
@@ -112,9 +86,7 @@ subroutine UCC_lda_exchange_energy(nEns,wEns,nCC,aCC,nGrid,weight,rho,Cx_choice,
 
     r = max(0d0,rho(iG))
 
-    if(r > threshold) then
-      Ex = Ex + weight(iG)*Cx*r**(4d0/3d0) 
-    endif
+    if(r > threshold) Ex = Ex + weight(iG)*Cx*r**(4d0/3d0) 
 
   enddo
 
diff --git a/src/eDFT/UCC_lda_exchange_individual_energy.f90 b/src/eDFT/UCC_lda_exchange_individual_energy.f90
index 7283a9c..cd0666e 100644
--- a/src/eDFT/UCC_lda_exchange_individual_energy.f90
+++ b/src/eDFT/UCC_lda_exchange_individual_energy.f90
@@ -39,18 +39,20 @@ subroutine UCC_lda_exchange_individual_energy(nEns,wEns,nCC,aCC,nGrid,weight,rho
   double precision,external     :: electron_number
 
 
-! Parameters for N -> N-1
+! Parameters for first state
 
   a1 = aCC(1,1)
   b1 = aCC(2,1)
   c1 = aCC(3,1)
 
-! Parameters for N -> N+1
+! Parameters for second state
 
   a2 = aCC(1,2)
   b2 = aCC(2,2)
   c2 = aCC(3,2)
 
+! Defining enhancements factor for weight-dependent functionals
+
   if(doNcentered) then
 
      w1 = wEns(2)
@@ -61,7 +63,6 @@ subroutine UCC_lda_exchange_individual_energy(nEns,wEns,nCC,aCC,nGrid,weight,rho
 
   else
 
-
     w1 = wEns(2)
     Fx1 = 1d0 - w1*(1d0 - w1)*(a1 + b1*(w1 - 0.5d0) + c1*(w1 - 0.5d0)**2)
 
diff --git a/src/eDFT/UCC_lda_exchange_potential.f90 b/src/eDFT/UCC_lda_exchange_potential.f90
index a90951f..114a204 100644
--- a/src/eDFT/UCC_lda_exchange_potential.f90
+++ b/src/eDFT/UCC_lda_exchange_potential.f90
@@ -32,44 +32,19 @@ subroutine UCC_lda_exchange_potential(nEns,wEns,nCC,aCC,nGrid,weight,nBas,AO,rho
 
   double precision,intent(out)  :: Fx(nBas,nBas)
 
-! Single excitation parameter
-
-!  a1 = 0.0d0
-!  b1 = 0.0d0
-!  c1 = 0.0d0
-
-! Parameters for H2 at equilibrium
-
-! a2 = +0.5751782560799208d0
-! b2 = -0.021108186591137282d0
-! c2 = -0.36718902716347124d0
-
-! Parameters for stretch H2
-
-!  a2 = + 0.01922622507087411d0
-!  b2 = - 0.01799647558018601d0
-!  c2 = - 0.022945430666782573d0
-
-! Parameters for He
-
-! a2 = 1.9125735895875828d0
-! b2 = 2.715266992840757d0
-! c2 = 2.1634223380633086d0
-
-! Parameters for He N -> N-1
+! Parameters for first state
 
   a1 = aCC(1,1)
   b1 = aCC(2,1)
   c1 = aCC(3,1)
  
-! Parameters for He N -> N+1
+! Parameters for second state
 
   a2 = aCC(1,2)
   b2 = aCC(2,2)
   c2 = aCC(3,2)
 
-! Fx1 for states N and N-1
-! Fx2 for states N and N+1
+! Defining enhancements factor for weight-dependent functionals
 
   if(doNcentered) then