I should have been more explicit rather than assuming the reader
would realize that entering a verb (Pi in this case) displays its
definition. Further, in the spirit of the Subject line, I should
enhance my Pi verb a bit by changing it to:
Pi=: (3: + j.~) ": [: (<....@o. % ]) 10"_ ^ x:
NB. so that things were formatted in a prettier manner
Pi 10 20
3.1415926535 3.14159265358979323846
actually, for Dieter's original question, I should have stuck to the
things John Randall supplied (I did mention the J essay in my message
too) and suggested that Dieter try something like:
pi =: [: (<....@o. % ]) 10"_ ^ x:
pi 10
6283185307r2000000000
pi 10 20
6283185307r2000000000 157079632679489661923r50000000000000000000
because this returns results (to the requested precision) in numeric
form that can be used in further computations, including formatting,
e.g.
0j20 ": pi 10 20
3.14159265350000000000 3.14159265358979323846
notice that pi 10 produces a number that is less "accurate" than the
floating point representtaion given by o.1 directly.
Dieter, you do have to pay attention to the rules for number
formation etc., but many times expressions such as mine above include
the blanks mainly to help your eyes parse the expression - the pi
verb above works find with no blanks at all. But I would say it is
harder to read.
pi=:[:(<....@o.%])10"_^x:
pi 10 20
6283185307r2000000000 157079632679489661923r50000000000000000000
At 13:39 -0400 2009/08/08, Devon McCormick wrote:
>Dieter -
>
>I think your confusion stems from this:
>
>Joey K Tuttle <[email protected]> (on Fri, Aug 7, 2009 at 1:54 PM) included part
>of a J session:
>> Pi 50
>> 3.14159265358979323846264338327950288419716939937510
>> Pi
> > (2: + j.~) ": [: (<....@o. % ]) 10"_ ^ x:
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