first impressions on trying to introduce my self t J (after 30 or so
years of APL)
I am making my way through the Lab mathematical roots of J
I am dyslexic and my math is rusty
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
I should be getting a general picture but I think there should be an
easier way to be led down the garden path
Donna
[EMAIL PROTECTED]
On 14-Jun-06, at 8:15 AM, John Randall wrote:
Chris Burke wrote:
I don't think Mathematica had any influence on J, though perhaps
APL had
a minor influence on Mathematica.
Mathematica was directly inspired by APL in certain operations,
notably
Map, Apply, Scan and Fold. Early versions of the Mathematica
documentation contained a lot of references to APL: these have
decreased
over time.
Much of the symbolic programming in Mathematica comes from Macsyma, in
particular the ideas of many different types for mathematical
expressions
assembled in a directed acyclic graph; the functional programming
idea of
remembering the result of every functional evaluation; and a knowledge
base of rules and heuristics for simplification of expressions. These
types of operations have no equivalent in APL or J, and there has been
little cross-pollination.
Mathematica (like everyone else) relies on LAPACK and other Fortran
libraries for hard-core numerical calculations.
Best wishes,
John
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