Neggia

XDS plugin that reads hdf5 files written by Dectris Eiger Detectors. Please note that a recent version of XDS (Version June 1, 2017 or later) is required for this to work.

Naming

Neggia - mountain pass in the Italian-speaking part of Switzerland pronounced "neh-jah". Wikipedia: https://en.wikipedia.org/wiki/Alpe_di_Neggia

HDF5 file compatibility requirements

/entry/instrument/detector/x_pixel_size
    type: float32 or float64
    if missing neggia will set qx to 0.0 when calling get_header()

/entry/instrument/detector/y_pixel_size
    type: float32 or float64
    if missing neggia will set qy to 0.0 when calling get_header()

/entry/instrument/detector/detectorSpecific/nimages
    type: any integer
    neggia will throw an error if value zero or negative

/entry/instrument/detector/detectorSpecific/ntrigger
    type: any integer
    neggia will throw an error if value zero or negative
    neggia will assume ntrigger = 1 if value is missing

/entry/instrument/detector/detectorSpecific/pixel_mask
    type: uint32
    chunking must be disabled
    neggia will apply pixel_mask and set data to
          -1 for pixel_mask & 0b00001
          -2 for pixel_mask & 0b11110
          -1 if data value larger than max of signed int32
    neggia will convert to uint32 if type is different and
    throw an error if any value is negative

/entry/data
    group must contain links to datasets:
    'data_000001' to 'data_999999'
    for a single h5 file without links to external datasets
    '/entry/data/data' will be used to extract image data
    all data must be chunked frame-wise

You can check the compatibility requirements by running our test script against your hdf5 master files:

pip3 install hdf5plugin h5py

bin/check_h5_compatibility.py your_master_file.h5

Neggia file support

For performance reasons neggia is parsing HDF5 files without the help of the official HDF5 library. Therefore we cannot always guarantee support for customly written files.

To test if our neggia plugin can open your file, build everything as described below down and run:

bin/check_h5_plugin your_master_file.h5

If neggia cannot open your HDF5 file you can enable CMake flag DEBUG_PARSING when building neggia. Neggia will then print a lot of parsing information which makes it easier to add parsing capabilities for new HDF5 object messages. Pull-requests here on github are welcome.

Build & Test

Please use only tagged release commits for your production environment. See https://github.com/dectris/neggia/releases

Prerequisites

gcc-4.8 or higher
On a centos6 machine install and enable devtoolset
- yum -y install centos-release-scl-rh
- yum install -y devtoolset-6-gcc-c++
- scl enable devtoolset-6 bash
cmake 3.6 or later
- CentOS: yum install -y cmake3
- OSX: install binary from https://cmake.org

Building

Use cmake or cmake3, depending on what your cmake version 3 executable is called.

mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
cmake --build .

The plugin file is found in build/src/dectris/neggia/plugin/dectris-neggia.so

Testing