From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail
From: "G.B." <bauhaus@futureapps.invalid>
Newsgroups: comp.lang.ada
Subject: Re: Everything You Know Is Wrong
Date: Tue, 29 Dec 2015 18:53:58 +0100
Organization: A noiseless patient Spider
Message-ID: <n5uh6q$chh$1@dont-email.me>
References: <n5nbml$v32$1@dont-email.me> <n5r0su$lts$1@dont-email.me>
 <n5r5sb$sgs$1@speranza.aioe.org>
 <alpine.DEB.2.11.1512281721030.14144@Lydia.insomnia247.nl>
 <n5rrjq$gg3$1@speranza.aioe.org>
 <alpine.DEB.2.11.1512281938090.14144@Lydia.insomnia247.nl>
 <n5s6nj$ch8$1@speranza.aioe.org> <n5tre9$t7c$1@dont-email.me>
 <n5tuo8$1cn$1@speranza.aioe.org> <n5u2uf$nrc$1@dont-email.me>
 <n5u4kl$hob$1@speranza.aioe.org> <n5udss$vh2$1@dont-email.me>
 <n5ugbf$fqr$1@speranza.aioe.org>
Reply-To: nonlegitur@futureapps.de
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Tue, 29 Dec 2015 17:51:22 -0000 (UTC)
Injection-Info: mx02.eternal-september.org;
 posting-host="b96887e80893c84a90c3007226ca0d1c";
	logging-data="12849"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX1+TBLrQYnN2Wl0cUbxn89QTDEufjt54K10="
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0)
 Gecko/20100101 Thunderbird/38.5.0
In-Reply-To: <n5ugbf$fqr$1@speranza.aioe.org>
Cancel-Lock: sha1:fMI5fmc54AC+df+6szg4crUx75U=
Xref: news.eternal-september.org comp.lang.ada:28927
Date: 2015-12-29T18:53:58+01:00
List-Id: <comp.lang.ada>

On 29.12.15 18:36, Dmitry A. Kazakov wrote:
> On 2015-12-29 17:57, G.B. wrote:
>
>> The point is that, since order does not matter among these parallel
>> computations, and since parallel loops are not just fantasy,
>> the possibility of postponement follows from parallel loops.
>
> Ada does not have parallel loops.

Ada is about to have parallel loops. Ada compilers already produce
code for parallel execution of loop bodies on today's processors.


>> Consider F1 and F2 from a Pure package, X a variable of type T
>> and T without progenitors:
>>
>>     declare
>>        A : T := F1 (1,2,3);
>>        B : T := F2 (X);
>>     begin
>>        G (A, B);
>>     end;
>>
>> Is it impossible for a compiler to see that the initializing parts of
>> the declarations of A and B are independent?
>
> No, because initialization of T may have side effects.

I assume you meant Yes, impossible. But,
if F1 and F2 are from a Pure package, is the compiler allowed to
ignore side effects because the programmer specified Pure? I think
that follows.

> BTW, why do you believe that the same amount of computation performed
> consecutively should require less energy or (not quite same) less
> battery drain?

Less energy at a certain point in time. Postpone calling sub if, say,
a photocell should first be given time to recharge a battery while
while regular operation continues, then call sub.