#$=head1 NAME
#$
#$mspef  - find prediction error filter
#$
#$=head1 SYNOPSIS
#$
#$C<call find_pef(dd,aa,niter)>
#$
#$=head1 INPUT PARAMETERS
#$
#$=over 4
#$
#$=item dd  -  C<real(:)>   
#$
#$      Input data
#$
#$=item niter - integer     
#$
#$      Number of itterations
#$
#$=back
#$
#$=head1 OUTPUT PARAMETERS
#$
#$=over 4
#$
#$=item  aa - type(msfilter)  
#$
#$       output filter
#$
#$=back
#$
#$=head1 DESCRIPTION
#$
#$ Find multi-scale prediction-error filter (helix magic)
#$
#$=head1 SEE ALSO
#$
#$L<npef>,L<hconest>,L<solver>,L<cgstep>,L<mshelix>
#$
#$=head1 LIBRARY
#$
#$B<geef90>
#$
#$=cut

module mspef {         # Find multi-scale prediction-error filter (helix magic)
  use mshconest
  use cgstep_mod
  use solver_mod
contains
  subroutine find_pef( yy, aa, niter) {
    integer,             intent( in)              :: niter
    real, dimension( :), pointer                  :: yy
    type( msfilter)                               :: aa
    integer                                       :: is
    real, dimension( size( yy), size( aa%lag, 2)) :: dd
    do is = 1, size( dd, 2)
       dd( :,is) = -yy
    call mshconest_init( yy, aa)
    call solver( mshconest_lop, cgstep, aa%flt, pack( dd, .true.), 
                 niter, x0= aa%flt)
    call cgstep_close()
    }
}