language defined list of prime numbers

language defined list of prime numbers

[Mehdi Saada]

Does the norm compel compilers to provide a descent list of prime numbers ? I can't find "prime" in the RM. 

Re: language defined list of prime numbers

[Mr. Man-wai Chang]

On 9/12/2017 11:57 PM, Mehdi Saada wrote:
> Does the norm compel compilers to provide a descent list of prime numbers ? I can't find "prime" in the RM.
>

I think prime numbers are not a number series. You have to specify the 
range for a list of prime numbers, don't you?

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Re: language defined list of prime numbers

[Mehdi Saada]

I might not get what you mean. I just supposed it should mandatory to provide a list of all prime numbers between 0 and let's say, 5000 at least, in the form of a function returning the next prime after N.
I have to write a function to simplify fractions, and I very doubt the teacher wants us at this point, to implement an whole algorithm to find prime numbers (up to the squared root), just for that.

Re: language defined list of prime numbers

[Jeffrey R. Carter]

On 12/09/2017 06:05 PM, Mehdi Saada wrote:
> I might not get what you mean. I just supposed it should mandatory to provide a list of all prime numbers between 0 and let's say, 5000 at least, in the form of a function returning the next prime after N.
> I have to write a function to simplify fractions, and I very doubt the teacher wants us at this point, to implement an whole algorithm to find prime numbers (up to the squared root), just for that.

To simplify fractions, all you need is the GCD algorithm.

-- 
Jeff Carter
"Ada has made you lazy and careless. You can write programs in C that
are just as safe by the simple application of super-human diligence."
E. Robert Tisdale
72

Re: language defined list of prime numbers

[Mr. Man-wai Chang]

On 10/12/2017 1:13 AM, Jeffrey R. Carter wrote:
> On 12/09/2017 06:05 PM, Mehdi Saada wrote:
>> I might not get what you mean. I just supposed it should mandatory to
>> provide a list of all prime numbers between 0 and let's say, 5000 at
>> least, in the form of a function returning the next prime after N.
>> I have to write a function to simplify fractions, and I very doubt the
>> teacher wants us at this point, to implement an whole algorithm to
>> find prime numbers (up to the squared root), just for that.
>
> To simplify fractions, all you need is the GCD algorithm.
>

How about using the algorithm to calculate all prime numbers then store 
them in a table? That should solve the efficiency problem. How about 
pre-loading the table into memory? :)

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Re: language defined list of prime numbers

[Mehdi Saada]

It does ring a bell now, that GCD stuff. But it was so much time ago, I could only think of using primes.
I'll forgot about primes for now, it's too much for now. I prefer to concentrate on Ada more than on math, as I can do the later after.

Re: language defined list of prime numbers

[Mr. Man-wai Chang]

On 10/12/2017 3:17 AM, Mehdi Saada wrote:
> It does ring a bell now, that GCD stuff. But it was so much time ago, I could only think of using primes.
> I'll forgot about primes for now, it's too much for now. I prefer to concentrate on Ada more than on math, as I can do the later after.

I suspect prime numbers could be used in generating unique keys for 
databases. Anyway...

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Re: language defined list of prime numbers

[Dirk Heinrichs]

Am 13.12.2017 um 11:41 schrieb Mr. Man-wai Chang:

> I suspect prime numbers could be used in generating unique keys for
> databases. Anyway...

What's wrong about (big-)int or uuid for this? Or did I miss some
esoteric new trend?

Bye...

	Dirk
-- 
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Re: language defined list of prime numbers

[Mr. Man-wai Chang]

On 15/12/2017 1:58 PM, Dirk Heinrichs wrote:
> Am 13.12.2017 um 11:41 schrieb Mr. Man-wai Chang:
>
>> I suspect prime numbers could be used in generating unique keys for
>> databases. Anyway...
>
> What's wrong about (big-)int or uuid for this? Or did I miss some
> esoteric new trend?

I don't remember them using prime numbers.

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Re: language defined list of prime numbers

[Dirk Heinrichs]

Am 15.12.2017 um 12:41 schrieb Mr. Man-wai Chang:
> On 15/12/2017 1:58 PM, Dirk Heinrichs wrote:
>> Am 13.12.2017 um 11:41 schrieb Mr. Man-wai Chang:
>>
>>> I suspect prime numbers could be used in generating unique keys for
>>> databases. Anyway...
>>
>> What's wrong about (big-)int or uuid for this? Or did I miss some
>> esoteric new trend?
> 
> I don't remember them using prime numbers.

Right. Why should they do so? Again: what's the point in using prime
numbers for generating unique DB keys when there are already multiple
well-proven mechanisms in place?

Bye...

	Dirk
-- 
Dirk Heinrichs <dirk.heinrichs@altum.de>
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Re: language defined list of prime numbers

[Dennis Lee Bieber]

On Sat, 9 Dec 2017 07:57:52 -0800 (PST), Mehdi Saada <00120260a@gmail.com>
declaimed the following:

>Does the norm compel compilers to provide a descent list of prime numbers ? I can't find "prime" in the RM. 


	"Prime number" is a concept just like "odd" and "even". No compiler
that I know of provides such as an inherent data type -- they must be
determined at run-time via an algorithm you have to provide. For
"odd"/"even" that algorithm is rather simple, using a simple modulo 2
operation. For "prime number" the algorithm becomes time consuming unless
one caches results for future use -- Google "Sieve of Eratosthenes" -- the
larger the prime number, the more time it takes to compute it.
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

Re: language defined list of prime numbers

[Mehdi Saada]

okay, thanks. It was probably in the part of the course I can't do because gtkada failed >_>