multidimensional sort

multidimensional sort

[Gilbert Gosseyn]

I want to sort an n-dim array by ascending dimensions and ascending elements as keys, in Ada. For example:
consider an array with n = 5 like:

((5, 8, 21, 37, 46), (5, 7, 12, 19, 26),
 (10, 12, 19, 33, 44), (7, 8, 34, 36, 38), (5, 11, 12, 27, 32), (10, 
  16, 30, 41, 45), (10, 13, 19, 40, 45), (10, 11, 18, 32, 41), (11, 
  28, 34, 37, 38))

which shall become

((5, 7, 12, 19, 26), (5, 8, 21, 37, 46), (5, 11, 12, 27, 32), (7, 8, 
  34, 36, 38), (10, 11, 18, 32, 41), (10, 12, 19, 33, 44), (10, 13, 
  19, 40, 45), (10, 16, 30, 41, 45), (11, 28, 34, 37, 38))

How to store, how to sort, and how to deallocate the original?

Thank you for your advice.

Re: multidimensional sort

[Petter Fryklund]

Den tisdag 17 mars 2020 kl. 13:31:43 UTC+1 skrev Gilbert Gosseyn:
> I want to sort an n-dim array by ascending dimensions and ascending elements as keys, in Ada. For example:
> consider an array with n = 5 like:
> 
> ((5, 8, 21, 37, 46), (5, 7, 12, 19, 26),
>  (10, 12, 19, 33, 44), (7, 8, 34, 36, 38), (5, 11, 12, 27, 32), (10, 
>   16, 30, 41, 45), (10, 13, 19, 40, 45), (10, 11, 18, 32, 41), (11, 
>   28, 34, 37, 38))
> 
> which shall become
> 
> ((5, 7, 12, 19, 26), (5, 8, 21, 37, 46), (5, 11, 12, 27, 32), (7, 8, 
>   34, 36, 38), (10, 11, 18, 32, 41), (10, 12, 19, 33, 44), (10, 13, 
>   19, 40, 45), (10, 16, 30, 41, 45), (11, 28, 34, 37, 38))
> 
> How to store, how to sort, and how to deallocate the original?
> 
> Thank you for your advice.

This looks very much like homework. Have a look at Ada.Containers.Indefinate_Vectors and the generic procedure Generic_Sorting.


Regards,
Petter 

Re: multidimensional sort

[Simon Wright]

Petter Fryklund <petter.fryklund@atero.se> writes:

> Den tisdag 17 mars 2020 kl. 13:31:43 UTC+1 skrev Gilbert Gosseyn:
>> I want to sort an n-dim array by ascending dimensions and ascending
>> elements as keys, in Ada. For example:
>> consider an array with n = 5 like:
>> 
>> ((5, 8, 21, 37, 46), (5, 7, 12, 19, 26),
>>  (10, 12, 19, 33, 44), (7, 8, 34, 36, 38), (5, 11, 12, 27, 32), (10, 
>>   16, 30, 41, 45), (10, 13, 19, 40, 45), (10, 11, 18, 32, 41), (11, 
>>   28, 34, 37, 38))
>> 
>> which shall become
>> 
>> ((5, 7, 12, 19, 26), (5, 8, 21, 37, 46), (5, 11, 12, 27, 32), (7, 8, 
>>   34, 36, 38), (10, 11, 18, 32, 41), (10, 12, 19, 33, 44), (10, 13, 
>>   19, 40, 45), (10, 16, 30, 41, 45), (11, 28, 34, 37, 38))
>> 
>> How to store, how to sort, and how to deallocate the original?
>> 
>> Thank you for your advice.
>
> This looks very much like homework. Have a look at
> Ada.Containers.Indefinate_Vectors and the generic procedure
> Generic_Sorting.

Unless OP has some unstated requirements, I'd think that just
Ada.Containers.Generic_Array_Sort would do the trick:

   type Arr is array (1 .. 5) of Positive;
   type Arrays is array (Positive range <>) of Arr;
   function "<" (L, R : Arr) return Boolean;

   procedure Sort is new Ada.Containers.Generic_Array_Sort
     (Index_Type   => Positive,
      Element_Type => Arr,
      Array_Type   => Arrays);

The trick is to get "<" right!

OP, what's wrong with

   Data : Arrays :=
     ((5, 8, 21, 37, 46),
      (5, 7, 12, 19, 26),
      ...
      (11, 28, 34, 37, 38));

which doesn't need deallocation at all.

Re: multidimensional sort

[Simon Wright]

Simon Wright <simon@pushface.org> writes:

> Unless OP has some unstated requirements, I'd think that just
> Ada.Containers.Generic_Array_Sort would do the trick:

I should have said, ARM A.18.26(2),
http://www.ada-auth.org/standards/rm12_w_tc1/html/RM-A-18-26.html#p2

Re: multidimensional sort

[Jeffrey R. Carter]

On 3/17/20 1:31 PM, Gilbert Gosseyn wrote:
> I want to sort an n-dim array by ascending dimensions and ascending elements as keys, in Ada. For example:
> consider an array with n = 5 like:
> 
> ((5, 8, 21, 37, 46), (5, 7, 12, 19, 26),
>   (10, 12, 19, 33, 44), (7, 8, 34, 36, 38), (5, 11, 12, 27, 32), (10,
>    16, 30, 41, 45), (10, 13, 19, 40, 45), (10, 11, 18, 32, 41), (11,
>    28, 34, 37, 38))

This appears to be a 2-D array, not 5, or perhaps a 1-D array of 1-D arrays with 
5 components, so I'm not sure what you're asking in general. What would it look 
like for n = 4?

-- 
Jeff Carter
"Gentlemen, you can't fight in here. This is the War Room!"
Dr. Strangelove
30

multidimensional sort

[Optikos]

This StackOverflow answer should ba significant step to solving your problem:

https://stackoverflow.com/questions/17548979/defining-multiple-elements-of-a-multi-dimensional-array