Introduction

Tcl package to read and write HDF5 format files.

Description

The hdf5 package is a simple wrapper that provide some functionality of the C++ HDF5 library (www.hdfgroup.org/HDF5) at Tcl level.

HDF5 is a file format and C++ library to store datasets of numbers in an efficient way for scientific or engineering use.
It is basically a collection of groups and datasets organized in a tree shape. The group is similar to a directory of the filesystem.
The dataset is a vector of integer, floats, doubles, strings or compound data. The dataset can be optionally compressed. Every group or dataset is referenced in a way similar to a file in a filesystem. For example, "/group1/groups2/dataset1" refers to the dataset dataset1 that is stored inside group group2 that is stored inside group1. group1 is stored in the root of the file.
Every group or dataset can contain an arbitrary number of attributes, which are collections of name, value pairs.

Capabilities of the package:

It permits to read and write uni, bi, and tri-dimensional arrays of integer, float, double, string and compound types.
for multi-dimensional arrays, the size of each dimension must be specified, and is stored C-like (ordered by rows, opposite to FORTRAN-like)
For storing a set of coordinates, for example, one would store a vector of integers and three vectors of double
For efficiency the arrays are converted to and from a specialized tcl_obj that can hold a vector of integer, float or double. If this vector is used in TCL, it can be converted to-from a Tcl string or list.
It is possible to create groups and list or delete objects in them. It is possible to apply or read string attributes to every dataset or group as strings. Every string is inherently stored as utf-8., but can be set as a special string HDF5 data