Thanks for all the comments and help in understanding why trying to get an extended integer result from a square root is a bad idea.
I think the functional symmetry of square *: and square root %: led me to subconsciously forget that the results of squared integers (all integers) are not symmetrical with the results of the square roots of integers (which are NOT all integers). I should remember this, since one of my favorite J idioms is the implicit verb (=>.) for finding integers in a list of floating point numbers: a=.2+i.20 %:a 1.41421 1.73205 2 2.23607 2.44949 2.64575 2.82843 3 3.16228 3.31662 3.4641 3.60555 3.74166 3.87298 4 4.12311 4.24264 4.3589 4.47214 4.58258 (=>.)%:a 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 a#~(=>.)%:a 4 9 16 Skip ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
