diff --git a/Makefile b/Makefile
index dd997d9..2962eb7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 IRPF90 = irpf90/bin/irpf90 --codelet=factor_een:2 --align=4096 # -s nelec_8:504 -s nnuc:100 -s ncord:5 #-a -d
-FC     = ifort -xCORE-AVX512 -g -mkl=sequential  -qopt-zmm-usage=high 
-#FC     = ifort -xCORE-AVX2 -g -mkl=sequential  
+#FC     = ifort -xCORE-AVX512 -g -mkl=sequential  -qopt-zmm-usage=high 
+FC     = ifort -xCORE-AVX2 -g -mkl=sequential  
 FCFLAGS= -O3 -I .
 NINJA  = ninja
 ARCHIVE = ar crs
diff --git a/el_nuc_el.irp.f b/el_nuc_el.irp.f
index 3560d57..c991702 100644
--- a/el_nuc_el.irp.f
+++ b/el_nuc_el.irp.f
@@ -36,7 +36,7 @@ BEGIN_PROVIDER [ double precision, factor_een ]
 
 END_PROVIDER
 
-BEGIN_PROVIDER [ double precision, factor_een_deriv_e, (4, nelec) ]
+BEGIN_PROVIDER [ double precision, factor_een_deriv_e, (nelec,4) ]
   implicit none
   BEGIN_DOC
 ! Derivative of the Jeen
@@ -45,10 +45,10 @@ BEGIN_PROVIDER [ double precision, factor_een_deriv_e, (4, nelec) ]
   integer                        :: i, j, a, p, k, l, lmax, m, n
   double precision               :: cn, accu, accu2, daccu(1:4), daccu2(1:4)
   
-!  factor_een_deriv_e(1:4,1:nelec) = factor_een_deriv_e_blas(1:4,1:nelec)
+!  factor_een_deriv_e(1:nelec,1:4) = factor_een_deriv_e_blas(1:4,1:nelec)
 !  return
   
-  factor_een_deriv_e(1:4,1:nelec) = 0.0d0
+  factor_een_deriv_e(1:nelec,1:4) = 0.0d0
   
   do n = 1, dim_cord_vect
     
@@ -79,11 +79,11 @@ BEGIN_PROVIDER [ double precision, factor_een_deriv_e, (4, nelec) ]
               rescale_een_n(i,a,m+l)
           
         enddo
-        factor_een_deriv_e(1:4,j) = factor_een_deriv_e(1:4,j) +      &
+        factor_een_deriv_e(j,1:4) = factor_een_deriv_e(j,1:4) +      &
             (accu * rescale_een_n_deriv_e(j,1:4,a,m+l) + daccu(1:4) * rescale_een_n(j,a,m+l) +&
             daccu2(1:4)* rescale_een_n(j,a,m) + accu2*rescale_een_n_deriv_e(j,1:4,a,m)) * cn
         
-        factor_een_deriv_e(4,j) = factor_een_deriv_e(4,j) + 2.d0*(   &
+        factor_een_deriv_e(j,4) = factor_een_deriv_e(j,4) + 2.d0*(   &
             daccu (1) * rescale_een_n_deriv_e(j,1,a,m+l) +           &
             daccu (2) * rescale_een_n_deriv_e(j,2,a,m+l) +           &
             daccu (3) * rescale_een_n_deriv_e(j,3,a,m+l) +           &
@@ -96,7 +96,7 @@ BEGIN_PROVIDER [ double precision, factor_een_deriv_e, (4, nelec) ]
 
 END_PROVIDER
 
-BEGIN_PROVIDER [ double precision, factor_een_deriv_e_ref, (4, nelec) ]
+BEGIN_PROVIDER [ double precision, factor_een_deriv_e_ref, (nelec,4) ]
  implicit none
  BEGIN_DOC
  ! Dimensions 1-3 : dx, dy, dz
@@ -152,14 +152,14 @@ BEGIN_PROVIDER [ double precision, factor_een_deriv_e_ref, (4, nelec) ]
                       d2 = drjam_cn(ii) * riam
                       lap1 = lap1 + d1 * d2
                       lap2 = lap2 + drijk(ii) * drjal(ii)
-                      factor_een_deriv_e_ref(ii, j) = factor_een_deriv_e_ref(ii, j) + v1 * d2 + d1 * v2
+                      factor_een_deriv_e_ref(j,ii) = factor_een_deriv_e_ref(j,ii) + v1 * d2 + d1 * v2
                    enddo
 
                    ! v(x) u''(x) + 2 * u'(x) v'(x) + u(x) v''(x)
                    ii = 4
                    d1 = drijk(ii) * rial + rijk * drjal(ii) + lap2 + lap2
                    d2 = drjam_cn(ii) * riam
-                   factor_een_deriv_e_ref(ii, j) = factor_een_deriv_e_ref(ii, j) + v1 * d2 + d1 * v2 + lap1 + lap1
+                   factor_een_deriv_e_ref(j,ii) = factor_een_deriv_e_ref(j,ii) + v1 * d2 + d1 * v2 + lap1 + lap1
 
                 enddo
              enddo
diff --git a/el_nuc_el_blas.irp.f b/el_nuc_el_blas.irp.f
index c5d5660..3a39825 100644
--- a/el_nuc_el_blas.irp.f
+++ b/el_nuc_el_blas.irp.f
@@ -21,10 +21,12 @@
 
  ! dr_{ij}^k . R_{ja}^l -> dtmp_c_{ia}^{kl}
  do k=0,ncord-1
-   call dgemm('N','N', 4*nelec, nnuc*(ncord+1), nelec, 1.d0,         &
-       rescale_een_e_deriv_e(1,1,1,k), 4*size(rescale_een_e_deriv_e,1),&
-       rescale_een_n(1,1,0), size(rescale_een_n,1), 0.d0,            &
-       dtmp_c(1,1,1,0,k), 4*size(dtmp_c,1))
+   call dgemm('N','N', 4*nelec_8, nnuc*(ncord+1), nelec, 1.d0,         &
+       rescale_een_e_deriv_e(1,1,1,k),                               &
+       size(rescale_een_e_deriv_e,1)*size(rescale_een_e_deriv_e,2),  &
+       rescale_een_n(1,1,0),                                         &
+       size(rescale_een_n,1), 0.d0,                                  &
+       dtmp_c(1,1,1,0,k), size(dtmp_c,1)*size(dtmp_c,2))
  enddo
 
 
@@ -80,7 +82,6 @@ END_PROVIDER
            )*cn2
      enddo
 
-
      do ii=1,4
        do j=1,nelec
          factor_een_deriv_e_blas(j,ii) = factor_een_deriv_e_blas(j,ii) + (&
diff --git a/jastrow.irp.f b/jastrow.irp.f
index 01af425..f86c2cf 100644
--- a/jastrow.irp.f
+++ b/jastrow.irp.f
@@ -1,5 +1,6 @@
 program jastrow
   implicit none
+  print *, 'Number of electrons: ', nelec
   print *, 'The total Jastrow factor'
   print *, jastrow_full
   print *, 'REF'
@@ -7,7 +8,12 @@ program jastrow
   print *, 'X'
   print *, factor_een_deriv_e
   print *, 'BLAS'
-  print *, factor_een_deriv_e_blas
+  print *, factor_een_deriv_e_blas(1:nelec,1:4)
+  print *, ''
+  print *, factor_een_deriv_e_ref(1:nelec,1) - factor_een_deriv_e_blas(1:nelec,1)
+  print *, factor_een_deriv_e_ref(1:nelec,2) - factor_een_deriv_e_blas(1:nelec,2)
+  print *, factor_een_deriv_e_ref(1:nelec,3) - factor_een_deriv_e_blas(1:nelec,3)
+  print *, factor_een_deriv_e_ref(1:nelec,4) - factor_een_deriv_e_blas(1:nelec,4)
   !PROVIDE jastrow_full
 
 end program