Ok thank you Marcus and Marcus for your answers. GNURadio is really awesome and this feature will be great in my opinion.
Marcus (the first) said: "However, you can loop *internally* within a block." How can i do that? Thx Thomas Le 17 mai 2017 10:56, "Marcus Müller" <marcus.muel...@ettus.com> a écrit : > Adding to that, because it comes up every couple of years: > > Marcus is right, GNU Radio's scheduler will just bark at you and refuse to > work if the flow graph has cycles. > > I don't fully agree with the statement that it's due to buffer management: > > I've patched away that refusal to work on a longish train ride some time > ago, and in theory, with the Thread-Per-Block (TPB) scheduler, it *would* > work. However, of course, you're running into causality problems if none of > the blocks in the feedback path creates items out of thin air, and the > block where feedback and forward items "merge" needs an item on every input. > > So, realizing that this refusal to work is a result of GNU Radio > originally being written only with the single-threaded scheduler (STS) in > mind, and is a remnant of us never really having codified or formalized the > boundaries between blocks, block execution, scheduling, and flowgraph > initialization, I kinda stopped there, and never wrote the unit and > integration tests, wrote docs or figured out a way to test whether such a > flow graph could work before actually letting it start to run. > > It just seemed wiser to *first* tackle the fact that we don't really have > a formal description of how the scheduler should behave before changing > what it refuses to do (and, possibly, for good reasons that I didn't have > in mind). Now, fast forward a while, what a surprise!, that plan of > formalizing what GR is supposed to do never saw execution; it's not really > a weekend project. > > But: this whole thing has gotten traction over the last couple of weeks, > so maybe we'll come up with something. > > Cheers, > Marcus (the second) > > On 16.05.2017 22:39, Marcus D. Leech wrote: > > On 05/16/2017 04:01 PM, Thom L wrote: > > Hi, > For educational purposes I try to use gnuradio to realize simple digital > filters with delay, add and multiply blocks. > This is perfect for non-recursive filters but it does not seem possible to > make loops as in the example above and thus impossible to build a recursive > filter on the same principle? > Thanks > Thomas > > > _______________________________________________ > Discuss-gnuradio mailing > listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > Loops are strictly forbidden by the buffer-management model. > > However, you can loop *internally* within a block. > > > > > _______________________________________________ > Discuss-gnuradio mailing > listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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