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<div class="moz-cite-prefix">Le 19/08/2021 à 17:04, Naeem Khoshnevis
a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CAKOOZvMJjtXRUcn4WMKRajOo4a=4jE16NePrKmOT+G4g8St7Rg@mail.gmail.com">
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<p
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">Thank
you so much, everyone, for responding to this email.</span></p>
<p
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><br>
</p>
<p
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">Dirk,</span></p>
<ul
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt">
<li
style="background:transparent;margin-top:0pt;margin-bottom:0pt;list-style-type:disc"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">I didn't
think about testing _equality_ of doubles because the
numbers are significantly different (e.g., instead of 0.5,
chooses 1.5). However, that is a valid point, and I should
be aware of that.</span></li>
<li
style="background:transparent;margin-top:0pt;margin-bottom:0pt;list-style-type:disc"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">You are
right about the serial runs. Whenever I deactivate OpenMP,
the results are correct.</span></li>
</ul>
<p
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><br>
</p>
<p
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">Serguei,</span></p>
<ul
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt">
<li
style="background:transparent;margin-top:0pt;margin-bottom:0pt;list-style-type:disc"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">Thanks
for the comments. Yes, I agree. It seems outer is a better
option. We have started with outer. However, outer builds
the entire matrix of differences first, then finds the
minimum index. In our application, it requires 200 GB of
memory to build that matrix.</span></li>
</ul>
</div>
</blockquote>
<p>This problem was hardly foreseeable from examples in hand. But I
still think that a pure R solution can be a runner:</p>
<p> ac=a*sc<br>
bc=b*sc<br>
out=vapply(seq_along(bc), function(i)
which.min(abs(ac-bc[i])+cd[i]), integer(1))<br>
</p>
<p>Best,<br>
Serguei.<br>
</p>
<blockquote type="cite"
cite="mid:CAKOOZvMJjtXRUcn4WMKRajOo4a=4jE16NePrKmOT+G4g8St7Rg@mail.gmail.com">
<div dir="ltr">
<ul
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt">
<li
style="background:transparent;margin-top:0pt;margin-bottom:0pt;list-style-type:disc"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt"> Rcpp
does the job with around 10 MB. That is why I switched to
Rcpp. Please let me know your thoughts.</span></li>
</ul>
<p
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><br>
</p>
<h3
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt;font-weight:normal">Iñaki,</span></span></h3>
<ul
style="color:rgb(14,16,26);background:transparent;margin-top:0pt;margin-bottom:0pt">
<li
style="background:transparent;margin-top:0pt;margin-bottom:0pt;list-style-type:disc"><span
style="background:transparent;margin-top:0pt;margin-bottom:0pt">Thanks
for your suggestion. Yes, the problem is shared values,
and it resolved the issue. I really appreciate it. </span></li>
</ul>
<div><font color="#0e101a"><br>
</font></div>
<div><font color="#0e101a">Best regards,</font></div>
<div><font color="#0e101a">Naeem </font></div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, Aug 19, 2021 at 4:56
AM Iñaki Ucar <<a href="mailto:iucar@fedoraproject.org"
moz-do-not-send="true">iucar@fedoraproject.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On
Thu, 19 Aug 2021 at 04:53, Dirk Eddelbuettel <<a
href="mailto:edd@debian.org" target="_blank"
moz-do-not-send="true">edd@debian.org</a>> wrote:<br>
><br>
><br>
> Naeem,<br>
><br>
> I would simplify, simplify, simplify -- as 'Rcpp FAQ
7.31' reminds us all,<br>
> testing _equality_ of doubles is challenging anyway.<br>
><br>
> Besides, it may make sense to would ascertain first you
get what you want in<br>
> _purely serial modes_ and then move to OpenMP.<br>
<br>
Exactly. Serial execution should be fine. I.e., if you set the
number<br>
of threads to 1, then all platforms will return the same
result.<br>
However, you have defined a number of variables outside the
parallel<br>
region, and then you modify them inside the parallel region.
OpenMP<br>
takes those variables as shared by default, which leads to the<br>
unexpected results you are getting. You need to tell OpenMP
that those<br>
variables are threadprivate. Or you could just define them
inside the<br>
parallel region, so that OpenMP knows that they are private
without<br>
additional hints.<br>
<br>
-- <br>
Iñaki Úcar<br>
</blockquote>
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