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    <title>topic non deterministic results for ippsDiv_32f_I in Intel® Integrated Performance Primitives</title>
    <link>https://community.intel.com/t5/Intel-Integrated-Performance/non-deterministic-results-for-ippsDiv-32f-I/m-p/1703402#M29107</link>
    <description>&lt;P class=""&gt;&lt;SPAN class=""&gt;I'm using Intel Integrated Performance Primitives (windows, v2019 (2019.0.5.1052), 64bit) and I came across unexpected results.&lt;/SPAN&gt;&lt;/P&gt;&lt;P class=""&gt;&lt;SPAN class=""&gt;When I run the following code&amp;nbsp;&lt;BR /&gt;&lt;BR /&gt;&lt;/SPAN&gt;&lt;/P&gt;&lt;LI-CODE lang="cpp"&gt;const int N = 20;
std::vector&amp;lt;float&amp;gt; a(N, 1.0209482f);
const std::vector&amp;lt;float&amp;gt; b(N,0.032953884f);
    

ippsDiv_32f_I(b.data(), a.data(), N);
std::cout &amp;lt;&amp;lt; "result : " &amp;lt;&amp;lt; a[0] &amp;lt;&amp;lt; std::endl;&lt;/LI-CODE&gt;&lt;P class=""&gt;sometimes I get&amp;nbsp;30.981117 and sometimes&amp;nbsp;30.98112&lt;BR /&gt;&lt;BR /&gt;Even though initially&amp;nbsp;&lt;EM&gt;a&lt;/EM&gt; and &lt;EM&gt;b&lt;/EM&gt; contain equal values, after calling&amp;nbsp;ippsDiv_32f_I values in &lt;EM&gt;a&lt;/EM&gt; varies.&lt;BR /&gt;At each run it gives me different output.&lt;BR /&gt;&lt;BR /&gt;&lt;/P&gt;&lt;P class=""&gt;I understand that that the function has some degree of accuracy. I wouldn't expect non-deterministic behaviour.&lt;/P&gt;&lt;P class=""&gt;&amp;nbsp;&lt;/P&gt;&lt;P class=""&gt;Is it expected ? documented ?&lt;BR /&gt;&lt;a href="https://community.intel.com/t5/user/viewprofilepage/user-id/46774"&gt;@Ruqiu_C_Intel&lt;/a&gt;&amp;nbsp;,&amp;nbsp;&lt;a href="https://community.intel.com/t5/user/viewprofilepage/user-id/41889"&gt;@Gennady_F_Intel&lt;/a&gt;&amp;nbsp;&lt;/P&gt;</description>
    <pubDate>Tue, 15 Jul 2025 08:31:38 GMT</pubDate>
    <dc:creator>Josephnyu</dc:creator>
    <dc:date>2025-07-15T08:31:38Z</dc:date>
    <item>
      <title>non deterministic results for ippsDiv_32f_I</title>
      <link>https://community.intel.com/t5/Intel-Integrated-Performance/non-deterministic-results-for-ippsDiv-32f-I/m-p/1703402#M29107</link>
      <description>&lt;P class=""&gt;&lt;SPAN class=""&gt;I'm using Intel Integrated Performance Primitives (windows, v2019 (2019.0.5.1052), 64bit) and I came across unexpected results.&lt;/SPAN&gt;&lt;/P&gt;&lt;P class=""&gt;&lt;SPAN class=""&gt;When I run the following code&amp;nbsp;&lt;BR /&gt;&lt;BR /&gt;&lt;/SPAN&gt;&lt;/P&gt;&lt;LI-CODE lang="cpp"&gt;const int N = 20;
std::vector&amp;lt;float&amp;gt; a(N, 1.0209482f);
const std::vector&amp;lt;float&amp;gt; b(N,0.032953884f);
    

ippsDiv_32f_I(b.data(), a.data(), N);
std::cout &amp;lt;&amp;lt; "result : " &amp;lt;&amp;lt; a[0] &amp;lt;&amp;lt; std::endl;&lt;/LI-CODE&gt;&lt;P class=""&gt;sometimes I get&amp;nbsp;30.981117 and sometimes&amp;nbsp;30.98112&lt;BR /&gt;&lt;BR /&gt;Even though initially&amp;nbsp;&lt;EM&gt;a&lt;/EM&gt; and &lt;EM&gt;b&lt;/EM&gt; contain equal values, after calling&amp;nbsp;ippsDiv_32f_I values in &lt;EM&gt;a&lt;/EM&gt; varies.&lt;BR /&gt;At each run it gives me different output.&lt;BR /&gt;&lt;BR /&gt;&lt;/P&gt;&lt;P class=""&gt;I understand that that the function has some degree of accuracy. I wouldn't expect non-deterministic behaviour.&lt;/P&gt;&lt;P class=""&gt;&amp;nbsp;&lt;/P&gt;&lt;P class=""&gt;Is it expected ? documented ?&lt;BR /&gt;&lt;a href="https://community.intel.com/t5/user/viewprofilepage/user-id/46774"&gt;@Ruqiu_C_Intel&lt;/a&gt;&amp;nbsp;,&amp;nbsp;&lt;a href="https://community.intel.com/t5/user/viewprofilepage/user-id/41889"&gt;@Gennady_F_Intel&lt;/a&gt;&amp;nbsp;&lt;/P&gt;</description>
      <pubDate>Tue, 15 Jul 2025 08:31:38 GMT</pubDate>
      <guid>https://community.intel.com/t5/Intel-Integrated-Performance/non-deterministic-results-for-ippsDiv-32f-I/m-p/1703402#M29107</guid>
      <dc:creator>Josephnyu</dc:creator>
      <dc:date>2025-07-15T08:31:38Z</dc:date>
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