OK, I'm warned... just get the 5!:5 result right and I'll take responsibility for using it :) Anyway, I can't use 3!:n to talk to release 5, so I have no choice.
Henry Rich > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Roger Hui > Sent: Tuesday, August 15, 2006 9:40 PM > To: Beta forum > Subject: Re: RE: [Jbeta] Linear Representation > > Well, don't say I didn't warn you. > > > > ----- Original Message ----- > From: Henry Rich <[EMAIL PROTECTED]> > Date: Tuesday, August 15, 2006 6:34 pm > Subject: RE: [Jbeta] Linear Representation > > > With respect, I disagree. 3!:x changed for release 6, for > > example. As new datatypes are added, 5!:5 seems to me less > > likely to break. (This is not an academic issue: I have > > to keep J5.04 running to use it for DDE) > > > > I agree that to get floats right bit for bit 3!:n would > > be better. > > > > Henry Rich > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [EMAIL PROTECTED] On Behalf Of Roger Hui > > > Sent: Tuesday, August 15, 2006 9:26 PM > > > To: Beta forum > > > Subject: Re: [Jbeta] Linear Representation > > > > > > It is best to use 3!:x to exchange between machines > > > or to recover values in a session with perfect > > > fidelity. > > > > > > > > > > > > ----- Original Message ----- > > > From: Henry Rich <[EMAIL PROTECTED]> > > > Date: Tuesday, August 15, 2006 6:16 pm > > > Subject: RE: RE: [Jbeta] Linear Representation > > > > > > > I know I encountered this problem years ago, when > > > > 0$0 was changed to '' in the 5!:5 result (IIRC). I > > > > believe the 0$0 that I was using was boxed and > > > > was part of a list of boxes. > > > > > > > > Roger fixed that, and my problems went away. I > > > > am glad to see that Roger expects to change the error > > > > reported here, because the 5!:5 form is a good portable > > > > way to pass values between machines and versions, and > > > > it is important to make sure that the values received > > > > are the same ones that were sent. > > > > > > > > Henry Rich > > > > > > > > > -----Original Message----- > > > > > From: [EMAIL PROTECTED] > > > > > [EMAIL PROTECTED] On Behalf Of Roger Hui > > > > > Sent: Tuesday, August 15, 2006 6:34 PM > > > > > To: Beta forum > > > > > Subject: Re: RE: [Jbeta] Linear Representation > > > > > > > > > > > By the way, a particular application failed to > > > > > > run because a J6 empty vector turned out not to > > > > > > be 'identical' to the corresponding J5 empty > > > > > > vector and it was difficult to see, via their > > > > > > linear representation, that they were actually > > > > > > different in some sense. > > > > > > > > > > There had been no changes in 5!:5 on empty vectors > > > > > or boxed empty vectors between J6 and J5. > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > From: Jose Mario Quintana <[EMAIL PROTECTED]> > > > > > Date: Tuesday, August 15, 2006 2:17 pm > > > > > Subject: RE: [Jbeta] Linear Representation > > > > > > > > > > > > Behalf Of Mark D. Niemiec > > > > > > > Jose Mario Quintana > > > <[EMAIL PROTECTED]> wrote: > > > > > > > > "5!:5 y Linear. The linear representation is a string > > > > > which, when > > > > > > > > interpreted, produces the named object." > > > > > > > > > > > > > > [...] > > > > > > > > > > > > > > One of the idiosyncracies of empty arrays is that they are > > > > > > > considered equal, even if they have different data types. > > > > > > > This is rarely important, but the underlying data type can > > > > > > > reveal itself when fill elements are being used (as with > > {. > > > > or {:) > > > > > > > and certainly with 3!:0 > > > > > > > > > > > > > [...] > > > > > > > A problem with 5!:5 and 5!:6 is that they produce > > > > > > representations that are > > > > > > > equal to the original, but not necessarily > IDENTICAL in all > > > > > > > aspects. For example, they do not preserve type: > > > > > > > > > > > > > > type f0=:-~1.5 NB. real clone of 0 > > > > > > > 8 > > > > > > > f0 > > > > > > > 0 > > > > > > > type "[EMAIL PROTECTED]'f0' NB. This forgets the 'realness' of > > > > > > > the > > zero> > > > > 1 > > > > > > > f0+!20x NB. real 0 trumps extended precision > > > > > > > 2.4329e18 > > > > > > > ("[EMAIL PROTECTED]'f0')+!20x NB. freeze-dried and > > > > > > > reconstituted 0 > > > > does not > > > > > > > 2432902008176640000 > > > > > > > > > > > > > > (and, in the cited example, lr does not preserve the > > type of > > > > the > > > > > > empty> list either). > > > > > > > > > > > > > > > > > > > Behalf Of Roger Hui > > > > > > > It comes down to whether there is one empty vector > > > > > > > or more than one empty vector. (*) > > > > > > [...] > > > > > > > > > > > > > > I will probably change 5!:5 to preserve the > > > > > > > > > > > > That seems to make more sense than the alternative of > > > > clarifying > > > > > > that "when > > > > > > interpreted, produces the named object" but it might not > > > > always be > > > > > > 'identically' the same object. > > > > > > > > > > > > By the way, a particular application failed to run because > > a > > > > J6 > > > > > > empty vector > > > > > > turned out not to be 'identical' to the corresponding J5 > > empty > > > > > > vector and it > > > > > > was difficult to see, via their linear representation, > > that > > > > > they were > > > > > > actually different in some sense. > > > > > > > > > > > > > distinction between <i.0 and <'' without answering > > > > > > > (*) one way or the other. > > > ---------------------------------------------------------------------- > For information about J forums see > http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
