On Jan 5, 2012, at 7:36 AM, David Mertens wrote: > Yes, rank. Come to think of it, though, I was thinking "rank" would be a > good word in place of "number of dimensions," as in a rank-two piddle,
sounds like a piddle that has been sitting in the sun and rain and stinks. "Shape" or "dimension" seem/sound more natural as they convey a visual sense of the data. > rather than a two-dimensional piddle. > > The issue arises with describing data. For example, a point in three > dimensional space is described by a one dimensional piddle with three > elements. As you can see, the word "dimension" is used in two ways, one to > describe the extent of space, the other to describe the shape of the > piddle. Using the word "rank," we would say that a point in three > dimensional space is described by a rank-one piddle with three elements. > Because of the nature of my work and life, I tend to think in maps and space terms. Most intuitive for me is to think of a point as a 1D array with three elements. One would think that lots of points on a map would be best represented as a 1D array of 1D [x,y,z] arrays. However, a gridded dataset can be thought of a 2D array of data bundles where the x and y of the outer array describe the location (forgetting z values for the time being), and each data bundle is data about that location. So, one could have an nD array containing data at location [32, 450]. . . . 32 . . . . . . . . . . . . . . . . . 450 . . [*] . . . . . . . . . . . . . . . . . Layered maps turn into a 1D array of 2D array of 1D arrays where the outermost dimension would be t. Imagine, layers of rainfall measurements for every day for a given area. And so on. Coming from a world where I am used to arrays, substituting "piddle" for "array" seems the most natural to me, but probably is also my biggest stumbling block at ever getting even half as good at PDL as you all are. > A potential revised lexicon, then, would be this: > > dims -> shape > ndims -> rank > > In order of specificity, we would talk about a... > 3x5 piddle, > rank-two piddle > piddle > > One final, very deep annoyance that I have is with the term "thread." It > should be "autoloop." But that should wait until after 2.4.10 at the very > least. > > David > On Jan 5, 2012 4:48 AM, "Matthew Kenworthy" <[email protected]> > wrote: > >> The "shape" proposal is an *excellent* idea - it gets my vote! >> >> On Thu, Jan 5, 2012 at 5:17 AM, Craig DeForest >> <[email protected]>wrote: >> >>> Hrm. As long as we're on terminology, how do you describe a PDL with dim >>> list [3,5]? >>> >>> We've/I've been calling it a 2-D PDL with dim sizes 3 and 5 (as in "dim 0 >>> has size 3, and dim 1 has size 5"), or alternatively a 3x5-PDL. Its first >>> row would be called a 3-PDL or a 1-D PDL with size 3. >>> >>> >> My preference is "3x5 PDL" as "2d 3x5 PDL" is a bit redundant. >> >> I'd say no to "3-PDL" - I'd prefer "1-D PDL with size 3". >> >> "A PDL with shape 3 by 5" sounds good to me! >> >> Matt >> >> -- >> Matthew Kenworthy / Assistant Professor / Leiden Observatory >> Niels Bohrweg 2 (#463) / P.O. Box 9513 / 2300 RA Leiden / NL >> >> > _______________________________________________ > Perldl mailing list > [email protected] > http://mailman.jach.hawaii.edu/mailman/listinfo/perldl _______________________________________________ Perldl mailing list [email protected] http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
