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<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D">Stephane pointed out on the issue : after calculation and prior to the Acos one, some values were “1.0000000000000002220446” leading to “acos = 2.107D-08i” ; in addition he suggested
me to use something like “acos(max(-1,min(1,-1.0000000000000002220446)))” or “acos(max(-1,min(1,1.0000000000000002220446)))” … very smart
</span><span lang="EN-US" style="font-size:12.0pt;font-family:Wingdings;color:#1F497D">J</span><span lang="EN-US" style="font-size:12.0pt;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D">Paul<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p></o:p></p>
<p><b><i><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:gray">EXPORT CONTROL :
<br>
</span></i></b><b><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Cet email ne contient pas de données techniques<br>
This email does not contain technical data</span></b><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><a name="_____replyseparator"></a><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:FR">De :</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:FR">
users [mailto:users-bounces@lists.scilab.org] <b>De la part de</b> Stéphane Mottelet<br>
<b>Envoyé :</b> mardi 29 janvier 2019 16:59<br>
<b>À :</b> users@lists.scilab.org<br>
<b>Objet :</b> Re: [Scilab-users] [EXTERNAL] Re: acos leads to complex values<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">It is the same if x is slightly > 1:<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">--> x=1+%eps<br>
x = <br>
<br>
1.<br>
<br>
<br>
--> acos(x)<br>
ans =<br>
<br>
2.107D-08i <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<p class="MsoNormal">--> format(25); x <br>
x = <br>
<br>
1.0000000000000002220446 <o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Le 29/01/2019 à 16:55, Carrico, Paul a écrit :<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D">When I scroll to the list, the lowest (positive) value is 8.4<sup>E</sup>-08 (works fine) and no %eps .</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D">How Can I check if %eps is in?</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:12.0pt;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:FR">De :</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext;mso-fareast-language:FR"> users
[<a href="mailto:users-bounces@lists.scilab.org">mailto:users-bounces@lists.scilab.org</a>]
<b>De la part de</b> Stéphane Mottelet<br>
<b>Envoyé :</b> mardi 29 janvier 2019 16:50<br>
<b>À :</b> <a href="mailto:users@lists.scilab.org">users@lists.scilab.org</a><br>
<b>Objet :</b> [EXTERNAL] Re: [Scilab-users] acos leads to complex values</span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"> <o:p></o:p></p>
<div>
<p class="MsoNormal">Le 29/01/2019 à 16:45, Carrico, Paul a écrit :<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span lang="EN-US">Dear All</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">I spent some time in looking for a mistake in my code ; finally I’ve found that the ACOS of a real vector leads to some complex values (???)</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<pre><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#32B9B9">acos</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#4A55DB">(</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif"">Scar_P</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#4A55DB">(</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#FFAA00">:</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif"">,</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:rosybrown">1</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#4A55DB">)</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif""> </span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#5C5C5C">./</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif""> CM_x_CN</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#4A55DB">(</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#FFAA00">:</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif"">,</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:rosybrown">1</span><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif";color:#4A55DB">))</span><o:p></o:p></pre>
</blockquote>
<p>Are your really sure, because we may have<o:p></o:p></p>
<p>--> x=-1-%eps <br>
x = <br>
<br>
-1.<br>
<br>
<br>
--> acos(x)<br>
ans =<br>
<br>
3.1415927 - 2.107D-08i<o:p></o:p></p>
<p>S.<o:p></o:p></p>
<p> <o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<pre><span lang="ES" style="font-size:12.0pt;font-family:"Monospaced","serif""> </span><o:p></o:p></pre>
<p class="MsoNormal"><span lang="EN-US">(the formula worked so far)</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">I checked that the input values are correct:</span><o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]><span lang="EN-US">Comprised between [-1; 1] using MIN and MAX</span><o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]><span lang="EN-US">Composed only of real values using ISREAL (all the vectors are correct)</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">Thus I do not understand why complex values appear ?</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">May it come from the vectorization ?</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">Paul</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt"><br>
<br>
<br>
</span><o:p></o:p></p>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>users mailing list<o:p></o:p></pre>
<pre><a href="mailto:users@lists.scilab.org">users@lists.scilab.org</a><o:p></o:p></pre>
<pre><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__antispam.utc.fr_proxy_2_c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy_urldefense.proofpoint.com_v2_url-3Fu-3Dhttps-2D3A-5F-5Fantispam.utc.fr-5Fproxy-5F1-5Fc3RlcGhhbmUubW90dGVsZXRAdXRjLmZy-5Flists.scilab.org-5Fmailman-5Flistinfo-5Fusers-26d-3DDwMG-2Dg-26c-3D0hKVUfnuoBozYN8UvxPA-2Dw-26r-3D4TCz-2D-2D8bXfJhZZvIxJAemAJyz7Vfx78XvgYu3LN7eLo-26m-3DrN8DsnGalih7CBHModSb9evOi3rmZRFFYcBFHTC71gU-26s-3DRgKyyESZ7uSTxlU7V0nR42XTJybjC0Ar5fDcrouQThE-26e-3D&d=DwMG-g&c=0hKVUfnuoBozYN8UvxPA-w&r=4TCz--8bXfJhZZvIxJAemAJyz7Vfx78XvgYu3LN7eLo&m=gwQYJePMwf66Qkf2heyo1UqhkxA31D8XuF0dNsmnvOg&s=WFlVbPNytDi1qDLq35P7qeSGnwD6PCRMRL4tKAtS9no&e=">https://antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/lists.scilab.org/mailman/listinfo/users</a><o:p></o:p></pre>
</blockquote>
<p> <o:p></o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Stéphane Mottelet<o:p></o:p></pre>
<pre>Ingénieur de recherche<o:p></o:p></pre>
<pre>EA 4297 Transformations Intégrées de la Matière Renouvelable<o:p></o:p></pre>
<pre>Département Génie des Procédés Industriels<o:p></o:p></pre>
<pre>Sorbonne Universités - Université de Technologie de Compiègne<o:p></o:p></pre>
<pre>CS 60319, 60203 Compiègne cedex<o:p></o:p></pre>
<pre>Tel : +33(0)344234688<o:p></o:p></pre>
<pre><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__antispam.utc.fr_proxy_2_c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy_urldefense.proofpoint.com_v2_url-3Fu-3Dhttp-2D3A-5F-5Fwww.utc.fr-5F-2D7Emottelet-26d-3DDwMG-2Dg-26c-3D0hKVUfnuoBozYN8UvxPA-2Dw-26r-3D4TCz-2D-2D8bXfJhZZvIxJAemAJyz7Vfx78XvgYu3LN7eLo-26m-3DrN8DsnGalih7CBHModSb9evOi3rmZRFFYcBFHTC71gU-26s-3D34gC0H3RYWxwcKp7fr4bR5XFfy1acxO72YI9AYJJFhA-26e-3D&d=DwMG-g&c=0hKVUfnuoBozYN8UvxPA-w&r=4TCz--8bXfJhZZvIxJAemAJyz7Vfx78XvgYu3LN7eLo&m=gwQYJePMwf66Qkf2heyo1UqhkxA31D8XuF0dNsmnvOg&s=Z35_aByfKODglW8yDddkINmGp0XVNG2FnCHehVQ_xic&e=">http://www.utc.fr/~mottelet</a><o:p></o:p></pre>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:FR"><br>
<br>
<o:p></o:p></span></p>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>users mailing list<o:p></o:p></pre>
<pre><a href="mailto:users@lists.scilab.org">users@lists.scilab.org</a><o:p></o:p></pre>
<pre><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__antispam.utc.fr_proxy_1_c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy_lists.scilab.org_mailman_listinfo_users&d=DwMG-g&c=0hKVUfnuoBozYN8UvxPA-w&r=4TCz--8bXfJhZZvIxJAemAJyz7Vfx78XvgYu3LN7eLo&m=gwQYJePMwf66Qkf2heyo1UqhkxA31D8XuF0dNsmnvOg&s=DUbP9Ae1PnplwVsabbz8k-6A-ZRz3dLu7e5o5GI9yqU&e=">https://antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/lists.scilab.org/mailman/listinfo/users</a><o:p></o:p></pre>
</blockquote>
<p><o:p> </o:p></p>
<pre>-- <o:p></o:p></pre>
<pre>Stéphane Mottelet<o:p></o:p></pre>
<pre>Ingénieur de recherche<o:p></o:p></pre>
<pre>EA 4297 Transformations Intégrées de la Matière Renouvelable<o:p></o:p></pre>
<pre>Département Génie des Procédés Industriels<o:p></o:p></pre>
<pre>Sorbonne Universités - Université de Technologie de Compiègne<o:p></o:p></pre>
<pre>CS 60319, 60203 Compiègne cedex<o:p></o:p></pre>
<pre>Tel : +33(0)344234688<o:p></o:p></pre>
<pre><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.utc.fr_-7Emottelet&d=DwMG-g&c=0hKVUfnuoBozYN8UvxPA-w&r=4TCz--8bXfJhZZvIxJAemAJyz7Vfx78XvgYu3LN7eLo&m=gwQYJePMwf66Qkf2heyo1UqhkxA31D8XuF0dNsmnvOg&s=gdmVN-2pjNdKfA0yL_jVwCc5aMSV0eTSd7Qdt4ClIBo&e=">http://www.utc.fr/~mottelet</a><o:p></o:p></pre>
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