Donna, If you are dyslexic you probably should especially stay away from the Dictionary. Seriously. At least for a while. That I can tell as a victim of the same ailment. As a student I was keen on AI-sy stuff and had LISP books, but never actually got to learn LISP or understand how it works: it was an image of a bunch of parenthese on the one side, congnitive frames on the other and a big void in between. Until I had a class-full of time in a computer lab to find something to prevent from going to sleep. I wandered the disk drive and found a muLISP folder. It contained the labs (it actually had a different name) and I learnt LISP in one hour. In a later semester when the professor said that the basic structural element of LISP is a list -- no, it's a CONS pair, I corrected -- she was very surprised. There is a paragraph at the beginning of Dictionary of APL, which I could not find in Dictionary of J, that specifically warns against using it as a learning source for beginners. Instead, learning is suggested with practical activity by examples in the subject area close to the learner. Whereas the dictionary is meant to be a reference source. This approach is in accordance with the analogous learning of a natural foreign language (note: the native language is learnt without any dictionary at all.): you cannot learn a foregn language using a dictionary. Or, similarly, with any other theoretical book. It is believed by modern lingvo-psychologists (Chomsky?) that formal instruction (books) do not cause language learning. What they do is confirm what you already learnt. Learning happens with massive exposure to samples and activity, immitation is a big factor, plus our inborn code cracking ability, which rebuilds our own dictionary and grammar in the head. Then the book can help reorganize that a little, but every person will have their own unique set of rules in their heads. That's actually confirmed in your examples below: you discovered that the 'base' symbol and immediately formed your own rules, which were not completely confirmed by the book and produced contradictory experience. Then you corrected your rule and now it's closer to the one in the book. Learning is induced by positive reinforcement, which comes from successes, possible wi th small incremetal tasks and the pleasure of little discoveries and positive confirmations. This is why gradual and hands-on labs are very productive, as well as books like primer. Frustration inhibits learning, which comes from attempting too steep tasks or prematurely exposing to theoretical material, which does not relate to any prior experience. A special case is profound experience in a related, but significantly different area, like you have a vast experience in APL and expect J to be just another dialect. That is similar to what happens to experienced skiers who attempt snowboarding: most of those who tried did not switch or even liked it for the reason that they had so many bruises and pain that they simply could not stand it. At the same time, that snowboarding is considered easier to learn when you are a complete alpine novice.
----- Original Message ---- From: dly <[EMAIL PROTECTED]> To: General forum <[email protected]> Sent: Wednesday, June 14, 2006 11:56:14 AM Subject: Re: [Jgeneral] Mathematical Roots of J & more musings wow? if b is base why is 11b2 2 not 11b2 3 or 12b2 2 not 12b2 domain error 33bg 16 not 33bg 51 Constants and results are displayed in the default base 10 (a) why 11ba 10 not 11ba 11 Scientific notation raises the default base 10 by powers of 10 as in 1e1 10 3.45e6 3450000 Napier's constant which he denoted e in honour of Euler is given by 1x1 in J which similarly can be raised by powers of e (Not to be confused with Euler's constant which he denoted C and Macheroni denoted γ=0.5772156649) 1x1 2.71828 2x2 14.7781 ∏ is given by 1p1 in J which similarly can be raised to powers of ∏ 1p1 3.14159 2p2 19.7392 So why confuse the student with this? Negative integers following p and x indicate the use of reciprocals. For example, 2p_2 is two divided by π squared, and 2x_2 is two divided by the square of Euler's number. Why not just say that for e (exponent of 10), p (exponent of ∏) and x (exponent of e) can be negative or decimal numbers? Donna [EMAIL PROTECTED] On 14-Jun-06, at 9:42 AM, John Randall wrote: > dly wrote: > >> I get imaginary numbers 3j4 but at a loss why 1x1 for e >> I see 1r1 but where did this x come from? it doesn't say but it >> somehow seems to follow that 1p1 is PI >> > > Donna: > > The exponential numeric constants are explained in the system > documentation > > http://www.jsoftware.com/books/help/dictionary/dcons.htm > > and in Henry Rich's book > > http://www.jsoftware.com/books/help/jforc/ > applied_mathematics_in_j.htm#_Toc129570854 > > I guess e would have been better than x except that it had already > been > used for base 10 exponential notation. > > Best wishes, > > John > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
