[Scilab-users] Is this behavior of ifft / isreal correct?
Dear all, Consider M = 16 w = [ones(1,M/4),zeros(1,M/4)] w = [w(1:M/2), 0, conj(w($:-1:2))] v = ifft(w) isreal(v) The first 3 lines defines a real spectrum of a real signal, then the real signal is recovered and finally it is checked whether it is real or not. What puzzles me is that the result is T (true). However, the definition of the ifft() involves complex operations, so at some point the numbers must be converted to a complex representation such as 1. + 0.i so I would expect that the result included 0i so the result of the test should be F. Where is this null imaginary component removed? I don't say this is wrong, but it is perplexing if compared to much more simple operations such as sqrt(%i^4) which yields 1. + 0.i, a complex representation of real scalar 1. Maybe the fftw package is so refined to detect whether the result is actually real and removes the useless 0.i components? Regards, Federico Miyara -- El software de antivirus Avast ha analizado este correo electrónico en busca de virus. https://www.avast.com/antivirus ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] Sundials module, macOS preview
Hi Stéphane This looks very good! Cheers, Claus On 06-04-2022 19:35, Stéphane Mottelet wrote: Hi all, The next version of scilab will include a new module "Sundials". This module provides new full featured ODE solvers: arkode(), cvode() and DAE solver ida(), all handling complex numbers and dense/sparse/banded Jacobians. Each solver has specific features, e.g. ida() handles DAE, arkode() handles mixed implicit/explicit Runge-Kutta methods and cvode() can do forward sensitivity computation. The module also includes a general-purpose nonlinear system solver: kinsol(), who takes advantage of the module architecture (parsing, computation engine and SUNDIALS abstraction of various linear solvers). Current help pages can be found @ https://www.utc.fr/~mottelet/scilab/sundials/ and a macOS build including the new module is available at https://www.utc.fr/~mottelet/scilab_for_macOS.html I hope that a Windows build will be available in a near future, but in the meantime, comments from macOS users are welcome ! Enjoy ! ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
[Scilab-users] Sundials module, macOS preview
Hi all, The next version of scilab will include a new module "Sundials". This module provides new full featured ODE solvers: arkode(), cvode() and DAE solver ida(), all handling complex numbers and dense/sparse/banded Jacobians. Each solver has specific features, e.g. ida() handles DAE, arkode() handles mixed implicit/explicit Runge-Kutta methods and cvode() can do forward sensitivity computation. The module also includes a general-purpose nonlinear system solver: kinsol(), who takes advantage of the module architecture (parsing, computation engine and SUNDIALS abstraction of various linear solvers). Current help pages can be found @ https://www.utc.fr/~mottelet/scilab/sundials/ and a macOS build including the new module is available at https://www.utc.fr/~mottelet/scilab_for_macOS.html I hope that a Windows build will be available in a near future, but in the meantime, comments from macOS users are welcome ! Enjoy ! -- Stéphane Mottelet Ingénieur de recherche EA 4297 Transformations Intégrées de la Matière Renouvelable Département Génie des Procédés Industriels Sorbonne Universités - Université de Technologie de Compiègne CS 60319, 60203 Compiègne cedex Tel : +33(0)344234688 http://www.utc.fr/~mottelet ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
