% Writes a NeXus HDF5 file using matlab

disp 'Write a NeXus HDF5 file'
filename = 'prj_test.nexus.hdf5';
timestamp = '2010-10-18T17:17:04-0500';

% read input data
A = load('input.dat');
mr = A(:,1);
I00 = int32(A(:,2));

% clear out old file, if it exists

delete(filename);

% using the simple h5 interface, there is no way to create a group without
% first creating a dataset; creating the dataset creates all intervening
% groups.

% store x
h5create(filename,'/entry/mr_scan/mr',[length(mr)]);
h5write(filename,'/entry/mr_scan/mr',mr);
h5writeatt(filename,'/entry/mr_scan/mr','units','degrees');
h5writeatt(filename,'/entry/mr_scan/mr','long_name','USAXS mr (degrees)');

% store y
h5create(filename,'/entry/mr_scan/I00',[length(I00)],'DataType','int32');
h5write(filename,'/entry/mr_scan/I00',I00);
h5writeatt(filename,'/entry/mr_scan/I00','units','counts');
h5writeatt(filename,'/entry/mr_scan/I00','long_name','USAXS I00 (counts)');

% indicate that we are plotting y vs. x
h5writeatt(filename,'/','default','entry');
h5writeatt(filename,'/entry','default','mr_scan');
h5writeatt(filename,'/entry/mr_scan','signal','I00');
h5writeatt(filename,'/entry/mr_scan','axes','mr_scan');
h5writeatt(filename,'/entry/mr_scan','mr_scan_indices', int32(0));

% add NeXus metadata
h5writeatt(filename,'/','file_name',filename);
h5writeatt(filename,'/','file_time',timestamp);
h5writeatt(filename,'/','instrument','APS USAXS at 32ID-B');
h5writeatt(filename,'/','creator','basic_writer.m');
h5writeatt(filename,'/','NeXus_version','4.3.0');
h5writeatt(filename,'/','HDF5_Version','1.6'); % no 1.8 features used in this example
h5writeatt(filename,'/entry','NX_class','NXentry');
h5writeatt(filename,'/entry/mr_scan','NX_class','NXdata');


h5disp(filename);