# About the derivation in firls.m

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## About the derivation in firls.m

 Hello everyone And I hope this isn't the wrong list to send this to. I am trying to make a small program in C++ about filter design, and I am currently trying the least-squares algorithm, based on Selesnick's paper (the same one from firls.m). However, I would like to be able to also make type iii and iv filters, differentiators and Hilbert transformers, too, and I was looking through your firls.m file, where I got stuck at the derivation of "cos_ints2". If it's not too much to ask, can someone please let me know how did it get from the formula in the comment to the one in the function calculating "cos_ints2"? I can't figure it out, not even with wxMaxima by my side. In the extreme case that my beginner programming skills allow it, I would also like to be able to make the weights as a linear variable function, too, so I would guess that the q vector will follow about the same principles as the b vector, so I would like to try it out, even if my small program, most probably, will never leave the screen of my monitor. But, if I get "lucky" (one is allowed to dream), I will let you know. Vlad _______________________________________________ Help-octave mailing list [hidden email] https://lists.gnu.org/mailman/listinfo/help-octave
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## Re: About the derivation in firls.m

 On Apr 13, 2017 11:11 AM, "je suis" <[hidden email]> wrote:Hello everyone And I hope this isn't the wrong list to send this to. I am trying to make a small program in C++ about filter design, and I am currently trying the least-squares algorithm, based on Selesnick's paper (the same one from firls.m). However, I would like to be able to also make type iii and iv filters, differentiators and Hilbert transformers, too, and I was looking through your firls.m file, where I got stuck at the derivation of "cos_ints2". If it's not too much to ask, can someone please let me know how did it get from the formula in the comment to the one in the function calculating "cos_ints2"? I can't figure it out, not even with wxMaxima by my side. In the extreme case that my beginner programming skills allow it, I would also like to be able to make the weights as a linear variable function, too, so I would guess that the q vector will follow about the same principles as the b vector, so I would like to try it out, even if my small program, most probably, will never leave the screen of my monitor. But, if I get "lucky" (one is allowed to dream), I will let you know. Vlad _______________________________________________ Help-octave mailing list [hidden email] https://lists.gnu.org/mailman/listinfo/help-octave The Signal package maintainer is copied on this email, but the copyright notice in firls.m suggests it was written in 2006 by someone else. I cc'd that person here on the chance the email is still valid and they may be able to take a moment to help you out.Nick J. _______________________________________________ Help-octave mailing list [hidden email] https://lists.gnu.org/mailman/listinfo/help-octave
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## Re: About the derivation in firls.m

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## Re: About the derivation in firls.m

 > Yes, I’m still here. It has indeed been a very long time. I’ll try to take a > look at the code and see if I am able to answer your question. I know not everyone has the time for it, but I would like to know if this is still valid. I, for one, am patient, but if my patience interferes with someone else's life, then I'd rather not continue. Vlad _______________________________________________ Help-octave mailing list [hidden email] https://lists.gnu.org/mailman/listinfo/help-octave
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## Re: About the derivation in firls.m

 I don’t have the source code readily available. Can you show me where it is now? > On Apr 23, 2017, at 9:22 AM, je suis <[hidden email]> wrote: > >> Yes, I’m still here. It has indeed been a very long time. I’ll try to take a >> look at the code and see if I am able to answer your question. > > I know not everyone has the time for it, but I would like to know if > this is still valid. I, for one, am patient, but if my patience > interferes with someone else's life, then I'd rather not continue. > > Vlad _______________________________________________ Help-octave mailing list [hidden email] https://lists.gnu.org/mailman/listinfo/help-octave
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## Re: About the derivation in firls.m

 On Mon, Apr 24, 2017 at 11:28 AM, Quentin Spencer wrote:I don’t have the source code readily available. Can you show me where it is now? Signal repository:https://sourceforge.net/p/octave/signal/ci/default/tree/I believe it's under the inst/ folder _______________________________________________ Help-octave mailing list [hidden email] https://lists.gnu.org/mailman/listinfo/help-octave
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