HI Dongmyung, I guess we discussed this offline. I am just posting our discussion to the mailing list in case it is of interest to others. Cheers, Spencer. On 4 Feb 2021, at 19:42, Dongmyung Suh <dongmyung.suh@gmail.com<mailto:dongmyung.suh@gmail.com>> wrote: This email from dongmyung.suh@gmail.com<mailto:dongmyung.suh@gmail.com> originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list<https://spam.ic.ac.uk/SpamConsole/Senders.aspx> to disable email stamping for this address. Dear All, I am a user of Nektar ++, and learning its foundation with Sherwin's book, Spectral hp element method for CFD [2ed]. I have a small question, while I study the book. When the book explains the Gauss-Lobatto-Legendre formula for integration (pg.61) and differentiation (pg 68), *i are the roots of Jocobi polynomial. However, in other references (https://en.wikipedia.org/wiki/Gaussian_quadrature), they are the roots of Legendre polynomial. Which one is right? or both are correct? Please let me be clear about that. Thank you. Dongmyung Suh _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users