[Nexus] large Nexus files

Campbell, Branton branton_campbell at byu.edu
Tue Jul 18 03:34:14 BST 2006


Dear Nexus users,

Suppose that I have a large (much bigger than computer memory) 3D array
that I must create and write to a single Nexus dataset.  Also assume
that I must compute the array values in an apparently random order.
Have the Nexus developers envisioned an efficient way to use the Nexus
API routines to write these elements in random order (i.e. not in nice
rectangular slabs)?  In the past, I have used direct-access files for
this purpose.

Of course, I would be better off sticking to arrays that fit in memory.
But I envision situations where this will not be possible (thousands of
8MB images used to reconstruct large contiguous volumes of reciprocal
space), and where it will be very expensive to break the output array up
into slabs and calculate them one at a time.

Best wishes,
Branton

****************************************
Branton J. Campbell
Department of Physics & Astronomy
Brigham Young University
N261 ESC, BYU, Provo, UT 84602
Tel: 801-422-5758 Fax: 801-422-0553
Email: branton_campbell at byu.edu
http://www.physics.byu.edu/faculty/campbell/




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