A hook can save recomputation.
(computation with original data and reused me) (resuse me)
test=: [: %: ([: -: +/) * [: */ ([: -: +/) - ]
NB. play with the half factor
f=: 4 %~ [: %: [: */ (([ , (- +:))~ +/)
NB. shorter
NB. c o m p u t a t i o n r e u s e
g=: ([: %: [: */ [ , -)~ ([: -: +/)
g2=: ([: %: [: */ [ , -)~ -:@:(+/)
%/ (g , test) 3?@:$0
1
On 09/04/2018 08:00 AM, programming-requ...@forums.jsoftware.com wrote:
Date: Tue, 04 Sep 2018 11:50:43 +0000
From: Martin Kreuzer<i...@airkreuzer.com>
To:programm...@jsoftware.com
Subject: [Jprogramming] Tacit form: How to handle intermediate
result..?
Message-ID:
<5b8e71a5.1c69fb81.65e5c.4a9esmtpin_added_miss...@mx.google.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Hi all -
To calculate the area of a flat triangle, using Heron's formula,
A(a,b,c)= sqrt( s2*(s2-a)*(s2-b)*(s2-c) )
I wrote a simple function doing this:
* get the three sides (as list input y)
* compute the half perimeter s2
* build the differences s2-y
* build product
* take square root
My explicit solution looks like this
taher=: 13 : '%: s2 * */ s2-y [ s2=. -: +/ y'
and works
taher 3 4 5
6
Suggested tacit version looks like this (and works too)
tahert=: [: %: ([: -: +/) * [: */ ([: -: +/) - ]
Q: Is there a way to reference the intermediate result of ([: -: +/)
the half perimeter s2
within the tacit expression, as has been done in the explicit..?
[Guess the interpreter takes care of this anyway; my question aims at
whether a shorter formulation could be reached.]
Thanks
-M
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