2.1.5. HDF5 in Fortran with NAPI¶
Code examples are provided in this section that write 2-D data to a NeXus HDF5 file in F77, and F90 languages using the NAPI: NeXus Application Programmer Interface (frozen).
The following code reads a two-dimensional set counts
with dimension scales of t and phi using
local routines, and then writes a NeXus file containing a single
NXentry group and a single NXdata group.
This is the simplest data file that conforms to the NeXus standard.
2.1.5.1. NAPI F77 Example: write simple NeXus file¶
Note
The F77 interface is no longer being developed.
1 program WRITEDATA
2
3 include 'NAPIF.INC'
4 integer*4 status, file_id(NXHANDLESIZE), counts(1000,50), n_p, n_t, dims(2)
5 real*4 t(1000), phi(50)
6
7!Read in data using local routines
8 call getdata (n_t, t, n_p, phi, counts)
9!Open output file
10 status = NXopen ('NXFILE.NXS', NXACC_CREATE, file_id)
11 status = NXputcharattr
12 + (file_id, 'user', 'Joe Bloggs', 10, NX_CHAR)
13!Open top-level NXentry group
14 status = NXmakegroup (file_id, 'Entry1', 'NXentry')
15 status = NXopengroup (file_id, 'Entry1', 'NXentry')
16!Open NXdata group within NXentry group
17 status = NXmakegroup (file_id, 'Data1', 'NXdata')
18 status = NXopengroup (file_id, 'Data1', 'NXdata')
19!Output time channels
20 status = NXmakedata
21 + (file_id, 'time_of_flight', NX_FLOAT32, 1, n_t)
22 status = NXopendata (file_id, 'time_of_flight')
23 status = NXputdata (file_id, t)
24 status = NXputcharattr
25 + (file_id, 'units', 'microseconds', 12, NX_CHAR)
26 status = NXclosedata (file_id)
27!Output detector angles
28 status = NXmakedata (file_id, 'polar_angle', NX_FLOAT32, 1, n_p)
29 status = NXopendata (file_id, 'polar_angle')
30 status = NXputdata (file_id, phi)
31 status = NXputcharattr (file_id, 'units', 'degrees', 7, NX_CHAR)
32 status = NXclosedata (file_id)
33!Output data
34 dims(1) = n_t
35 dims(2) = n_p
36 status = NXmakedata (file_id, 'counts', NX_INT32, 2, dims)
37 status = NXopendata (file_id, 'counts')
38 status = NXputdata (file_id, counts)
39 status = NXputattr (file_id, 'signal', 1, 1, NX_INT32)
40 status = NXputattr
41 + (file_id, 'axes', 'polar_angle:time_of_flight', 26, NX_CHAR)
42 status = NXclosedata (file_id)
43!Close NXdata and NXentry groups and close file
44 status = NXclosegroup (file_id)
45 status = NXclosegroup (file_id)
46 status = NXclose (file_id)
47
48 stop
49 end
2.1.5.2. NAPI F90 Example: write simple NeXus file¶
Note
This example uses the signal/axes attributes applied to the data field, as described in Associating plottable data by name using the axes attribute. New code should use the method described in Associating plottable data using attributes applied to the NXdata group.
1program WRITEDATA
2
3 use NXUmodule
4
5 type(NXhandle) :: file_id
6 integer, pointer :: counts(:,:)
7 real, pointer :: t(:), phi(:)
8
9!Use local routines to allocate pointers and fill in data
10 call getlocaldata (t, phi, counts)
11!Open output file
12 if (NXopen ("NXfile.nxs", NXACC_CREATE, file_id) /= NX_OK) stop
13 if (NXUwriteglobals (file_id, user="Joe Bloggs") /= NX_OK) stop
14!Set compression parameters
15 if (NXUsetcompress (file_id, NX_COMP_LZW, 1000) /= NX_OK) stop
16!Open top-level NXentry group
17 if (NXUwritegroup (file_id, "Entry1", "NXentry") /= NX_OK) stop
18 !Open NXdata group within NXentry group
19 if (NXUwritegroup (file_id, "Data1", "NXdata") /= NX_OK) stop
20 !Output time channels
21 if (NXUwritedata (file_id, "time_of_flight", t, "microseconds") /= NX_OK) stop
22 !Output detector angles
23 if (NXUwritedata (file_id, "polar_angle", phi, "degrees") /= NX_OK) stop
24 !Output data
25 if (NXUwritedata (file_id, "counts", counts, "counts") /= NX_OK) stop
26 if (NXputattr (file_id, "signal", 1) /= NX_OK) stop
27 if (NXputattr (file_id, "axes", "polar_angle:time_of_flight") /= NX_OK) stop
28 !Close NXdata group
29 if (NXclosegroup (file_id) /= NX_OK) stop
30!Close NXentry group
31 if (NXclosegroup (file_id) /= NX_OK) stop
32!Close NeXus file
33 if (NXclose (file_id) /= NX_OK) stop
34
35end program WRITEDATA