https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/VML-complex-functions-timing/m-p/811321#M3957 <DIV>Hi,</DIV><DIV></DIV><DIV>I was browsing the following page which lists the Clocks Per Element timing for all the VML functions.</DIV><A href="http://software.intel.com/sites/products/documentation/hpc/mkl/vml3/functions/_performanceall.html">http://software.intel.com/sites/products/documentation/hpc/mkl/vml3/functions/_performanceall.html</A><DIV></DIV><DIV>Does anyone else think the timings for the Complex functions seem suspect?</DIV><DIV></DIV><DIV>E.g.</DIV><DIV></DIV><DIV>Real Add : 0.79</DIV><DIV>Complex Add : 19.11</DIV><DIV></DIV><DIV>Surely Complex Add should only be 2x slower?</DIV><DIV></DIV> Tue, 01 Feb 2011 06:58:30 GMT Shueng_Chuan_Kiu 2011-02-01T06:58:30Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/VML-complex-functions-timing/m-p/811321#M3957 <DIV>Hi,</DIV><DIV></DIV><DIV>I was browsing the following page which lists the Clocks Per Element timing for all the VML functions.</DIV><A href="http://software.intel.com/sites/products/documentation/hpc/mkl/vml3/functions/_performanceall.html">http://software.intel.com/sites/products/documentation/hpc/mkl/vml3/functions/_performanceall.html</A><DIV></DIV><DIV>Does anyone else think the timings for the Complex functions seem suspect?</DIV><DIV></DIV><DIV>E.g.</DIV><DIV></DIV><DIV>Real Add : 0.79</DIV><DIV>Complex Add : 19.11</DIV><DIV></DIV><DIV>Surely Complex Add should only be 2x slower?</DIV><DIV></DIV> Tue, 01 Feb 2011 06:58:30 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/VML-complex-functions-timing/m-p/811321#M3957 Shueng_Chuan_Kiu 2011-02-01T06:58:30Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/VML-complex-functions-timing/m-p/811322#M3958 Complex add/sub functions support FP overflow error handling, while real add/sub functions do not guarantee that. This is the reason for difference in performance. Tue, 01 Feb 2011 11:42:35 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/VML-complex-functions-timing/m-p/811322#M3958 Ilya_B_Intel 2011-02-01T11:42:35Z