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<p>Hello.</p>
<p>The Pointset_Powerset domain has a difference_assign operator.<br>
If I remember correctly, when instantiated to used NNC_Polyhedron,<br>
the operator should be precise.</p>
<p>For instance:</p>
<p>pset1 = { A >= 0 }<br>
pset2 = { B = 0, A = 0 }<br>
pset1.difference_assign(pset2) = { A >= 0, B > 0 }, { A
>= 0, -B > 0 }, { B = 0, A > 0 }</p>
<p>Examples of its use (in the C++ interface) can be seen in</p>
<p> tests/Powerset/difference1.cc</p>
<p>where, however, it is instantiated with the C_Polyhedron class.</p>
<p>As for the Prolog interface, this should be the foreign predicate
to call:<br>
</p>
<p>extern "C" Prolog_foreign_return_type<br>
ppl_Pointset_Powerset_NNC_Polyhedron_difference_assign<br>
(Prolog_term_ref t_lhs, Prolog_term_ref t_rhs);<br>
</p>
<p>Let us know if it works as expected.<br>
</p>
Cheers,<br>
Enea.<br>
<br>
<br>
<div class="moz-cite-prefix">On 08/08/2017 02:39 PM,
<a class="moz-txt-link-abbreviated" href="mailto:j.c.vandepol@utwente.nl">j.c.vandepol@utwente.nl</a> wrote:<br>
</div>
<blockquote type="cite"
cite="mid:12810279-FC8D-4D45-A316-B8F94FF88EC5@utwente.nl">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Dear developers of PPL,
<div class=""><br class="">
</div>
<div class="">Is it possible to directly compute the
set-difference of two pointset powersets?</div>
<div class=""><br class="">
</div>
<div class="">In particular, I’m interested in the precise
complement; </div>
<div class="">convex difference approximations are not sufficient
for my case.</div>
<div class=""><br class="">
</div>
<div class="">Kind regards,</div>
<div class="">Jaco van de Pol</div>
<div class=""><br class="">
</div>
<div class=""><span style="orphans: 2; widows: 2;" class=""><br
class="">
</span></div>
<div class=""><span style="orphans: 2; widows: 2;" class="">--</span>
<div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap: break-word;
-webkit-nbsp-mode: space; -webkit-line-break:
after-white-space;" class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; word-spacing: 0px;
-webkit-text-stroke-width: 0px; word-wrap: break-word;
-webkit-nbsp-mode: space; -webkit-line-break:
after-white-space;" class="">
<span class="Apple-style-span" style="border-collapse:
separate; font-variant-ligatures: normal;
font-variant-east-asian: normal; font-variant-position:
normal; line-height: normal; border-spacing: 0px;">
<div style="word-wrap: break-word; -webkit-nbsp-mode:
space; -webkit-line-break: after-white-space;"
class="">
<div style="font-size: 12px;" class="">Prof. Jaco van
de Pol</div>
<div class="">University of Twente (NL)</div>
<div style="font-size: 12px;" class="">Formal Methods
and Tools </div>
<div style="font-size: 12px;" class=""><a
href="http://www.cs.utwente.nl/%7Evdpol" class=""
moz-do-not-send="true">http://www.cs.utwente.nl/~vdpol</a></div>
</div>
</span></div>
</div>
</div>
<br class="">
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</pre>
</blockquote>
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