Hi Eoin, We’ve found here that some of the Xilinx cores can be very sensitive to how you feed them and how they are configured. Have you tried looking for skipped transactions and missed beats? I would not have thought this core would be as sensitive to things as say their SSR FFT.
Alternatively have you managed to capture or look at the samples involved? Does the issue occurs near a 0, with small/large values, or around quadrant transitions. -Jeb Sent from my mobile. > On Dec 13, 2021, at 08:09, Hayden So <h...@eee.hku.hk> wrote: > > A while back my student developed a work to produce non-linear functions > for FPGA through various linear approximations and lookups with the goal to > minimize hw resources while maintaining good and quantifiable accuracy. It > included arctan among others: > > S. M. H. Ho and H. K. So, "NnCore: A parameterized non-linear function > generator for machine learning applications in FPGAs," 2017 International > Conference on Field Programmable Technology (ICFPT), 2017, pp. 160-167, doi: > 10.1109/FPT.2017.8280134. > > Code: > > https://bitbucket.org/hku-casr/nncore/src/master/ > > It's a bit dated but may be worth taking a look. > > Hope it helps. > > --Hayden > > > > Bob Stricklin wrote on 13/12/2021 11:54 PM: >> Consider making a lookup table. If your accuracy requirements and space will >> allow it. This is the way things use to be done before calculators and >> computers and it will work in a lot of cases. >> >> Bob Stricklin >> >>> On Dec 13, 2021, at 6:55 AM, baldwin <bald...@cp.dias.ie> wrote: >>> >>> Hi Guys, >>> >>> Quick question; I'm just wondering what is the best way to calculate arctan >>> on the FPGA? I am currently using the Xilinx CORDIC block to take I and Q >>> and use them to calculate phase, but have found this to give unreliable >>> data. While it sometimes gives out the correct phase value, it often just >>> gives completely nonsensical results. Just wondering if anybody else has >>> ever had similar issues. >>> >>> All the best, >>> >>> Eoin. >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "casper@lists.berkeley.edu" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to casper+unsubscr...@lists.berkeley.edu. >>> To view this discussion on the web visit >>> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/6a1e1ff7f781ec963db9c826b973adec%40cp.dias.ie. > > -- > /********************************************************** > * Hayden Kwok-Hay So > * Associate Professor > * Department of Electrical and Electronic Engineering > * Program Co-director, Computer Engineering > * Co-director, Joint Lab on Future Cities (JLFC) > * PI, Computer Architecture and System Research Lab (CASR) > * The University of Hong Kong > * http://www.eee.hku.hk/~hso > **********************************************************/ > -- > You received this message because you are subscribed to the Google Groups > "casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/697beb2c-a22c-7085-664e-c6d2603aa53a%40eee.hku.hk. -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. To unsubscribe from this group and stop receiving emails from it, send an email to casper+unsubscr...@lists.berkeley.edu. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/970E5BFF-A40E-4BFE-B2F1-A87F8D1383B1%40ucsb.edu.
