PNeXus.h File Reference

NeXus HDF4/HDF5 file reader and writer for muon spin rotation data. More...

#include <string>
#include <vector>
#include <map>
#include <cctype>
#include <algorithm>
#include <any>
#include <cstdint>
#include "Minuit2/FCNBase.h"
#include <mfhdf.h>
#include <hdf.h>
#include <H5Cpp.h>

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Classes
class	nxH4::PNeXusDeadTime
	Dead time correction calculator for muon detector data. More...
class	nxH4::PNXdata< T >
	Template class for storing HDF4 dataset content with attributes. More...
class	nxH4::PNeXus
	NeXus HDF4 file reader with case-insensitive path lookup. More...
class	nxH5::PNeXusDeadTime
	Dead time correction calculator for muon detector data. More...
class	nxH5::PNXdata< T >
	Template class for storing HDF5 dataset content with attributes. More...
class	nxH5::PNeXus
	NeXus HDF5 file reader with case-insensitive path lookup. More...

Namespaces
namespace	nxs
	Common utilities for NeXus file handling.
namespace	nxH4
	HDF4 implementation of the NeXus file reader/writer.
namespace	nxH5
	HDF5 implementation of the NeXus file reader/writer.

Enumerations
enum class	nxs::HDFType { nxs::HDF4 , nxs::HDF5 , nxs::Unknown }
	Enumeration of supported HDF file types. More...
enum class	nxH4::H4DataType {   nxH4::kINT32 , nxH4::kFLOAT32 , nxH4::kFLOAT64 , nxH4::kCHAR8 ,   nxH4::kUINT32 , nxH4::kINT16 , nxH4::kUINT16 , nxH4::kINT8 ,   nxH4::kUINT8 }
	HDF4 data type enumeration. More...

Functions
HDFType	nxs::checkHDFType (const std::string &filename)
	Determine the HDF format type of a file by reading its header.
std::string	nxs::getIso8601TimestampLocal ()
	get the current time and return it as na IOS8601 time stamp.

Detailed Description

NeXus HDF4/HDF5 file reader and writer for muon spin rotation data.

This header file defines the PNeXus library for reading and writing NeXus files in both HDF4 and HDF5 formats. The library is specifically designed for ISIS muon NeXus files but can be adapted for other NeXus data.

The library provides:

• Dual format support: Both HDF4 (nxH4 namespace) and HDF5 (nxH5 namespace)
• Case-insensitive path lookup: Handles varying path casings in NeXus files
• Type-safe data handling: Template-based PNXdata class with type preservation
• IDF version support: Handles both IDF version 1 and version 2 file structures
• Dead time correction: Built-in muon spectrometry dead time analysis

Architecture

The library is organized into three namespaces:

• nxs: Common utilities (HDFType enum, checkHDFType function)
• nxH4: HDF4-specific implementation (conditional, requires HAVE_HDF4)
• nxH5: HDF5-specific implementation (always available)

Data Organization

NeXus files follow the ISIS muon format with structure:

* /raw_data_1/                          (NXentry)
* ├── IDF_version
* ├── beamline, definition, run_number, title
* ├── start_time, end_time, good_frames
* ├── detector_1/                       (NXdata)
* │   ├── counts (multi-dimensional)
* │   ├── raw_time
* │   └── attributes (signal, axes, units, etc.)
* └── instrument/                       (NXinstrument)
*     ├── name, source/
*     └── detector_1/                   (NXdetector)
*         ├── counts, raw_time
*         ├── resolution, spectrum_index
*         └── dead_time
* 

Usage Example

#include "PNeXus.h"
 
// Check file type
nxs::HDFType type = nxs::checkHDFType("file.nxs");
 
if (type == nxs::HDFType::HDF5) {
    // Read HDF5 NeXus file
    nxH5::PNeXus nexus("file.nxs");
    nexus.Dump();
 
    // Access data
    auto counts = nexus.GetDataset<int>("/raw_data_1/detector_1/counts");
    auto dims = counts.GetDimensions();
}

Author

Andreas Suter

Date

2007-2026

Copyright

GNU General Public License v2

Version

1.0

See also

nxs::checkHDFType()

nxH4::PNeXus

nxH5::PNeXus

Definition in file PNeXus.h.