diff --git a/src/dav_general_mat/README.rst b/src/dav_general_mat/README.rst
index 5407a206..e528109f 100644
--- a/src/dav_general_mat/README.rst
+++ b/src/dav_general_mat/README.rst
@@ -1,4 +1,13 @@
-========
-test_dav
-========
+===============
+dav_general_mat
+===============
+
+This modules allows to use the Davidson Algorithm for general squared symmetric matrices 
+You have two options : 
+ a)  the routine "davidson_general" to whom you pass the matrix you want to diagonalize
+ b)  the routine "davidson_general_ext_rout" to whom you pass the subroutine that realizes v = H u 
+
+See the routines in "test_dav.irp.f" for a clear example. 
+
+
 
diff --git a/src/dav_general_mat/test_dav.irp.f b/src/dav_general_mat/test_dav.irp.f
index 7c2b8b9d..0a7faaf0 100644
--- a/src/dav_general_mat/test_dav.irp.f
+++ b/src/dav_general_mat/test_dav.irp.f
@@ -22,11 +22,14 @@ subroutine routine
  sze = N_det
  dim_in = sze
  dressing_state = 0
+ !!!! MARK THAT u_in mut dimensioned with "N_st_diag_in" as a second dimension 
  allocate(u_in(dim_in,N_st_diag_in),H_jj(sze),h_mat(sze,sze),energies(N_st))
  u_in = 0.d0
  do i = 1, N_st
   u_in(1,i) = 1.d0
  enddo
+ !!! Matrix "h_mat" is the matrix we want to diagonalize with the first routine 
+ !!! "davidson_general" 
  do i = 1, sze
   do j = 1, sze
    h_mat(j,i) = H_matrix_all_dets(j,i)
@@ -37,6 +40,8 @@ subroutine routine
  provide nthreads_davidson
  call davidson_general(u_in,H_jj,energies,dim_in,sze,N_st,N_st_diag_in,converged,h_mat)
  print*,'energies = ',energies 
+ !!! hcalc_template is the routine that computes v = H u 
+ !!! and you can use the routine "davidson_general_ext_rout" 
  call davidson_general_ext_rout(u_in,H_jj,energies,dim_in,sze,N_st,N_st_diag_in,converged,hcalc_template)
  print*,'energies = ',energies 
 end