Creating compound datatype with single dimension

Hdf-forum archives
1

Hi all,

Below is an excerpt from the HDF5 Fortran API example named
h5ex_t_cmpd_F03.f90
(http://www.hdfgroup.org/ftp/HDF5/examples/examples-by-api/hdf5-examples/1_8/FORTRAN/H5T/h5ex_t_cmpd_F03.f90).

After data were initialized, h5tcreate_f is called with H5OFFSETOF. If
wdata has more than one dimension, c_loc with H5OFFSETOF is enough to
create the compund datatype. My question is, assuming that wdata has
only one dimension, i.e. wdata(1), how should I formulate the second
c_loc command in H5OFFSETOF?

here is the excerpt:

   ! Initialize data.

  !
  wdata(1)%serial_no = 1153
  wdata(1)%location = "Exterior (static)"
  wdata(1)%temperature = 53.23_real_kind_15
  wdata(1)%pressure = 24.57_real_kind_15
  wdata(2)%serial_no = 1184
  wdata(2)%location = "Intake"
  wdata(2)%temperature = 55.12_real_kind_15
  wdata(2)%pressure = 22.95_real_kind_15
  wdata(3)%serial_no = 1027
  wdata(3)%location = "Intake manifold"
  wdata(3)%temperature = 103.55_real_kind_15
  wdata(3)%pressure = 31.23_real_kind_15
  wdata(4)%serial_no = 1313
  wdata(4)%location = "Exhaust manifold"
  wdata(4)%temperature = 1252.89_real_kind_15
  wdata(4)%pressure = 84.11_real_kind_15
  !
  ! Create a new file using the default properties.
  !
  CALL h5fcreate_f(filename, H5F_ACC_TRUNC_F, file, hdferr)
  !
  ! Create the compound datatype for memory.
  !
  CALL h5tcreate_f(H5T_COMPOUND_F, H5OFFSETOF(C_LOC(wdata(1)),
C_LOC(wdata(2))), memtype, hdferr)

Thank you in advance.

Regards,

Ekin

2

Assuming you have some derived type and array:

TYPE CmpField_struct
       INTEGER :: a
       REAL :: b
       REAL :: c
   ENDTYPE CmpField_struct

   TYPE(CmpField_struct), DIMENSION(1), TARGET :: cf

You can get the offset of a, b, or c of the derived type by:

offset = H5OFFSETOF(C_LOC(cf(1)),C_LOC(cf(1)%a))
offset = H5OFFSETOF(C_LOC(cf(1)),C_LOC(cf(1)%b))
offset = H5OFFSETOF(C_LOC(cf(1)),C_LOC(cf(1)%c))

Scot

···

________________________________
From: Hdf-forum <hdf-forum-bounces@lists.hdfgroup.org> on behalf of Ekin Akoglu <ekin@ims.metu.edu.tr>
Sent: Tuesday, February 04, 2014 1:05 PM
To: HDF Users Discussion List
Subject: [Hdf-forum] Creating compound datatype with single dimension

Hi all,

Below is an excerpt from the HDF5 Fortran API example named h5ex_t_cmpd_F03.f90 (http://www.hdfgroup.org/ftp/HDF5/examples/examples-by-api/hdf5-examples/1_8/FORTRAN/H5T/h5ex_t_cmpd_F03.f90).

After data were initialized, h5tcreate_f is called with H5OFFSETOF. If wdata has more than one dimension, c_loc with H5OFFSETOF is enough to create the compund datatype. My question is, assuming that wdata has only one dimension, i.e. wdata(1), how should I formulate the second c_loc command in H5OFFSETOF?

here is the excerpt:

   ! Initialize data.

  !
  wdata(1)%serial_no = 1153
  wdata(1)%location = "Exterior (static)"
  wdata(1)%temperature = 53.23_real_kind_15
  wdata(1)%pressure = 24.57_real_kind_15
  wdata(2)%serial_no = 1184
  wdata(2)%location = "Intake"
  wdata(2)%temperature = 55.12_real_kind_15
  wdata(2)%pressure = 22.95_real_kind_15
  wdata(3)%serial_no = 1027
  wdata(3)%location = "Intake manifold"
  wdata(3)%temperature = 103.55_real_kind_15
  wdata(3)%pressure = 31.23_real_kind_15
  wdata(4)%serial_no = 1313
  wdata(4)%location = "Exhaust manifold"
  wdata(4)%temperature = 1252.89_real_kind_15
  wdata(4)%pressure = 84.11_real_kind_15
  !
  ! Create a new file using the default properties.
  !
  CALL h5fcreate_f(filename, H5F_ACC_TRUNC_F, file, hdferr)
  !
  ! Create the compound datatype for memory.
  !
  CALL h5tcreate_f(H5T_COMPOUND_F, H5OFFSETOF(C_LOC(wdata(1)), C_LOC(wdata(2))), memtype, hdferr)

Thank you in advance.

Regards,

Ekin

3

Thank you, Scot. I also discovered to use "sizeof()" instead of
"H5OFFSETOF" & "c_loc" combination.

Regards,

Ekin

···

On 4 February 2014 20:51, Scot Breitenfeld <brtnfld@hdfgroup.org> wrote:

Assuming you have some derived type and array:

TYPE CmpField_struct
       INTEGER :: a
       REAL :: b
       REAL :: c
   ENDTYPE CmpField_struct

   TYPE(CmpField_struct), DIMENSION(1), TARGET :: cf

You can get the offset of a, b, or c of the derived type by:

offset = H5OFFSETOF(C_LOC(cf(1)),C_LOC(cf(1)%a))
offset = H5OFFSETOF(C_LOC(cf(1)),C_LOC(cf(1)%b))
offset = H5OFFSETOF(C_LOC(cf(1)),C_LOC(cf(1)%c))

Scot

------------------------------
*From:* Hdf-forum <hdf-forum-bounces@lists.hdfgroup.org> on behalf of
Ekin Akoglu <ekin@ims.metu.edu.tr>
*Sent:* Tuesday, February 04, 2014 1:05 PM
*To:* HDF Users Discussion List
*Subject:* [Hdf-forum] Creating compound datatype with single dimension

Hi all,

Below is an excerpt from the HDF5 Fortran API example named h5ex_t_cmpd_F03.f90 (http://www.hdfgroup.org/ftp/HDF5/examples/examples-by-api/hdf5-examples/1_8/FORTRAN/H5T/h5ex_t_cmpd_F03.f90).

After data were initialized, h5tcreate_f is called with H5OFFSETOF. If wdata has more than one dimension, c_loc with H5OFFSETOF is enough to create the compund datatype. My question is, assuming that wdata has only one dimension, i.e. wdata(1), how should I formulate the second c_loc command in H5OFFSETOF?

here is the excerpt:

   ! Initialize data.

  !
  wdata(1)%serial_no = 1153
  wdata(1)%location = "Exterior (static)"
  wdata(1)%temperature = 53.23_real_kind_15
  wdata(1)%pressure = 24.57_real_kind_15
  wdata(2)%serial_no = 1184
  wdata(2)%location = "Intake"
  wdata(2)%temperature = 55.12_real_kind_15
  wdata(2)%pressure = 22.95_real_kind_15
  wdata(3)%serial_no = 1027
  wdata(3)%location = "Intake manifold"
  wdata(3)%temperature = 103.55_real_kind_15
  wdata(3)%pressure = 31.23_real_kind_15
  wdata(4)%serial_no = 1313
  wdata(4)%location = "Exhaust manifold"
  wdata(4)%temperature = 1252.89_real_kind_15
  wdata(4)%pressure = 84.11_real_kind_15
  !
  ! Create a new file using the default properties.
  !
  CALL h5fcreate_f(filename, H5F_ACC_TRUNC_F, file, hdferr)
  !
  ! Create the compound datatype for memory.
  !
  CALL h5tcreate_f(H5T_COMPOUND_F, H5OFFSETOF(C_LOC(wdata(1)), C_LOC(wdata(2))), memtype, hdferr)

Thank you in advance.

Regards,

Ekin

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