dly <[EMAIL PROTECTED]> wrote: > So constants in J are strictly a memory aid and are otherwise treated > as any other variable? What a waste!
Remember that J (like most programming languages, and unlike symbolic mathematical languages like Maple and Mathematica) is designed for reasonable efficiency in calculations, rather than absolute mathematical accuracy. When you want to calculate, say, billing information for a million customers, it is more important to be able to perform the calculation in a reasonable amount of time to an accuracy of a fraction of a cent, rather than to take a year of CPU time to make sure that each one is accurate to an infinite number of decimal places. J's primary focus is the solving of practical problems, rather than being the end-all solution for abstract mathematical equations (something that symbolic languages are more suitable for). J peforms all its real calculations using efficient data types (machine integers and real number supported directly by the underlying hardware). If you want more precision, there are the extended and rational types provided to assist you (although to use them to obtain arbitrarily accurate approximations to irrational values, you have to do some of the additional work yourself). So, in J, mnemonics like 1p1 mean "as close to Pi as possible (given the architectural constraints)." This is the same meaning for Pi used by all other computing languages, desk calculators, etc. - other than places where symbolic math is performed. It would be quite burdensome on J if it had to have an additional data type to mean "exact representations of transcendental irrationals" - even if it did, the number of places in the language where such values could provide any kind of additional use which is more accurate than the current values is very limited. 1 2 3 o. 1p1*k NB. for any integer k ^.1x1*k NB. for any integer k Can you think of any others? Adding such an albatross to the language so that two (2) expressions happen to yield exact integers, rather than being off in the 16th binary place would be unjustifiable. -- Mark D. Niemiec <[EMAIL PROTECTED]> ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
