Gross mistake in Gamma-only stress for hybrid functionals

QEF · Jun 23, 2018 · 5ed1486 · 5ed1486
1 parent ae63562
commit 5ed1486
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diff --git a/Doc/release-notes b/Doc/release-notes
@@ -12,7 +12,7 @@ New in development version:
 
   * Spin-polarized X3LYP (experimental)
 
-  * EPW: Electronic transport (Botlzmann transport equation)
+  * EPW: Electronic transport (Boltzmann transport equation)
          Iterative Botlzmann transport equation (experimental)
          Cumulant treatement (model)
          Possible screening
@@ -21,6 +21,8 @@ New in development version:
 
 Problems fixed in development version:
 
+  * Stress with hybrid functionals and Gamma point was grossly wrong
+
   * EPW: Velocity in the dipole approximation was unstable because of 
     G-vector ordering. 
 

diff --git a/PW/src/exx.f90 b/PW/src/exx.f90
@@ -2634,11 +2634,11 @@ FUNCTION exx_stress()
 !$omp parallel do default(shared), private(ig), reduction(+:vc)
                         DO ig = 1, ngm
                             !
-                            vc(:,:) = vc(:,:) + fac(ig) * x1 * &
+                            vc(:,:) = vc(:,:) + x1 * 0.25_dp * &
                                       abs( rhoc(dfftt%nl(ig)) + &
                                       conjg(rhoc(dfftt%nlm(ig))))**2 * &
                                       (fac_tens(:,:,ig)*fac_stress(ig)/2.d0 - delta(:,:)*fac(ig))
-                            vc(:,:) = vc(:,:) + fac(ig) * x2 * &
+                            vc(:,:) = vc(:,:) + x2 * 0.25_dp * &
                                       abs( rhoc(dfftt%nl(ig)) - &
                                       conjg(rhoc(dfftt%nlm(ig))))**2 * &
                                       (fac_tens(:,:,ig)*fac_stress(ig)/2.d0 - delta(:,:)*fac(ig))