The amount of memory allocated for an array can be up to a factor of 2 larger than the minimum. The upside is that your faithful implementer would have room to achieve his nefarious ends (such as append-in-place), and also that the memory management for small blocks would be simplified. The downside is that the address space is used up faster than it would be otherwise.
----- Original Message ----- From: Michael Berry <[EMAIL PROTECTED]> Date: Friday, January 5, 2007 9:25 am Subject: [Jprogramming] How to interpret the space used by an array according to 7!:5 > The quick and helpful answers I get from this list encourage me to > ask more > questions. I hope that is OK. > > In my mental model of how things work, I imagine a J array to be > stored as a > fixed size header (or a header of size that is a function of the > array rank) > followed by the array contents. According to 7!:5, my floating > point array > seems to take up more space that that. This in on 32-bit Windows. > > > $rater_sig02 > 480189 19 > 8**/$rater_sig02 > 72988728 > 7!:5 <'rater_sig02' > 134217728 > (7!:5 <'rater_sig02')%*/$rater_sig02 > 14.7111 > > > In addition to just intellectual curiosity, my practical question > is whether > I need to think about anything beyond the number of elements and > the type of > my array when creating a mapped file to contain it. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
