Re: [Jprogramming] Simple example with (@.) 'Agenda'

[Martin Kreuzer]

Pascal -
Thanks for the quick answer;
I already worked the example from the NuVoc page 
using the prime exponents from (_ q:), I 
mentioned it here simply as a reference for result values.
My idea has been to stick with the straight approach (as an exercise) ...
-M
At 2016-07-12 16:14, you wrote:

__ q: each 16 17 18
┌─┬──┬───┐
│2│17│2 3│
│4│ 1│1 2│
└─┴──┴───┘


gives divisors as 2 rows with exponents as 2nd.


_ q: each 16 17 18
┌─┬─────────────┬───┐
│4│0 0 0 0 0 0 1│1 2│
└─┴─────────────┴───┘


just the exponents.

the 2nd program just increases these by 1, and takes product.



----- Original Message -----
From: Martin Kreuzer <i...@airkreuzer.com>
To: programm...@jsoftware.com
Sent: Tuesday, July 12, 2016 12:03 PM
Subject: [Jprogramming] Simple example with (@.) 'Agenda'

Hi all -

Tried a _straight approach_ to answer the question "How many divisors
does an (integer) number have?" ...

Hope my math is correct:

Check divisibility for all integers from 1 to floor of number's (square) root;
count number of divisor product pairs;
double that to get number of divisors and
subtract 1 in case of a square (integer root) which sports one
symmetrical pair.

This is what I put together:

    dn=. 13 : '(<:)`(]) @. (* (|~ %:) y) +: +/ -. * (>: i. <. %: y) | y'("0)
    dn 16 17 48 49 1024 1025 1103
5 2 10 3 11 6 2

As a comparison, here are the results using the example verb from the
NuVoc/ Prime Exponents page:

    don=. 13 : '*/ >: _ q: y'("0)
    don 16 17 48 49 1024 1025 1103
5 2 10 3 11 6 2

Guess verb (dn) can be written in a more compact way, sort of
"folding it" as it obviously has similar structural elements;

Q: Would someone have the time and patience to gently guide me through this..?

Thanks
-M

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