This suggestion makes sense to me. It is similar to NCO's
"leftermost product" (lfp) chunking map suggested by
Chris Barker. NCO adopted this as its default, so
users get it when they select chunk maps of type lfp or nco.
From the good book at
http://nco.sourceforge.net/nco.html#cnk
"Chunksize Lefter Product Matches Scalar Size Specified
Definition: The product of the chunksizes for each variable
(approximately) equals the size specified with the ‘--cnk_byt=sz_byt’
(not ‘--cnk_dfl’) option. This is accomplished by using dimension sizes
as chunksizes for the rightmost (most rapidly varying) dimensions, and
then “flexing” the chunksize of the leftmost (least rapidly varying)
dimensions such that the product of all chunksizes matches the specified
size. All L-dimensions to the left of and including the first record
dimension define the left-hand side. To be precise, if the total size
(in bytes) of the variable is var_sz, and if the specified (with
‘--cnk_byt’) product of the R “righter” dimensions (those that vary more
rapidly than the first record dimension) is sz_byt, then chunksize (in
bytes) of each of the L lefter dimensions is (approximately) the Lth
root of var_sz/sz_byt. This map was first proposed by Chris Barker.
cnk_map key values: ‘lfp’, ‘cnk_lfp’, ‘map_lfp’
Mnemonic: LeFter Product"
Charlie
--
Charlie Zender, Earth System Sci. & Computer Sci.
University of California, Irvine 949-891-2429 )'(
