In the header of an array, there is one word for the rank and one word (not byte) per dimension, plus a small, fixed number of words for miscellaneous items. So theoretically the maximum rank array in J64 is 8 %~ (_1+2^63) - f+1.
----- Original Message ----- From: Dan Bron <[email protected]> Date: Friday, October 23, 2009 11:39 Subject: Re: [Jgeneral] Advantages of using J in 64 bit OS To: General forum <[email protected]> > Roger wrote: > > http://www.jsoftware.com/jwiki/Essays/Covert%20Representation > > Neat! > > Theoretically speaking, what is the largest rank an array could > have in > 64-bit J, if I had "sufficient memory"? (Assuming > all the dimensions are > 0 or 1.) > > Is the structure of a 64-bit J header still "one machine word" > for the rank > of the array, and then one byte per dimension? If so, then > is the maximum > possible rank equal to the maximum value of a signed integer, > i.e _1+2^63 > ? > > I'm just asking because with my rank 2^28 example, I can "hide" > ~30MB of > data, and I'm wondering how much more I could (theoretically) hide. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
