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subroutine da_lanczos_io (io_config, cv_size, ntmaxit, neign, eignvec, eignval, qhat) 2,4
!-------------------------------------------------------------------------
! Purpose: Read / Write Lanczos eigenpairs
!
! Called from da_solve
!
! History: 08/16/2010 Creation (Tom Auligne)
!
!-------------------------------------------------------------------------
implicit none
character, intent(in) :: io_config ! 'r' = Read; 'w' = Write
integer, intent(inout) :: cv_size
integer, intent(in) :: ntmaxit
integer, intent(inout) :: neign
real*8, intent(inout) :: eignvec(ntmaxit, ntmaxit)
real*8, intent(inout) :: eignval(ntmaxit)
real, intent(inout) :: qhat(1:cv_size, 0:ntmaxit)
character(len=filename_len) :: filename ! I/O filename
character*10 :: cproc
integer :: ep_unit
integer :: i
if (trace_use) call da_trace_entry
("da_lanczos_io")
write(cproc,fmt='(i4.4)') myproc
filename = '../lanczos_eigenpairs.'//trim(adjustl(cproc))
call da_get_unit (ep_unit)
if (io_config == 'r') then
write(*,*) 'Reading Lanczos eigenpairs'
open (unit=ep_unit, file = filename, form = 'unformatted', status = 'old')
read(unit=ep_unit) neign, cv_size
do i = 1, neign
read(unit=ep_unit) eignval(i)
read(unit=ep_unit) eignvec(1:neign,i)
read(unit=ep_unit) qhat(1:cv_size,i)
end do
close(unit=ep_unit)
else if (io_config == 'w') then
write(*,*) 'Writing Lanczos eigenpairs'
open (unit=ep_unit, file = filename, form = 'unformatted', status = 'replace')
write(unit=ep_unit) neign, cv_size
do i = 1, neign
write(unit=ep_unit) eignval(i)
write(unit=ep_unit) eignvec(1:neign,i)
write(unit=ep_unit) qhat(1:cv_size,i)
end do
close(unit=ep_unit)
else
write(*,*) 'Unknow configuration for Lanczos I/O routine'
end if
call da_free_unit (ep_unit)
if (trace_use) call da_trace_exit ("da_lanczos_io")
end subroutine da_lanczos_io