Reply by Martin Brown May 29, 20222022-05-29
On 20/05/2022 18:46, whit3rd wrote:
> On Thursday, May 19, 2022 at 3:31:23 PM UTC-7, John Larkin wrote: > >> Yes, I work more by instinct and simulation. But my world is largely >> nonlinear, where the math is basically impossible. > > Identifying a problem as nonlinear IS math; it's obviously useful info, > and the only deficiency is in the non-utility of common approximations. > The math is not impossible, just... more difficult.
Quadratics are non-linear and taught as high school algebra. Cubics and their closed form solutions are seldom taught even at degree level. A few other non-linear closed form solutions are known up to quartics. After that it is what Pade approximations are designed for. They cause pure mathematicians to cross themselves and run out of the room. That aside on a good day you can get a workable and insightful approximations for real problems that are good enough for engineering. Their first serious use was in taming highly divergent and hard won series expansions for high Mach number turbulent flow in aerospace. The crucial point is that they are neither provably right nor exact but over some moderate range of your choosing can be made good enough for all practical purposes (or used as a guess for NR/Halley refinement). -- Regards, Martin Brown
Reply by David Eather May 27, 20222022-05-27
On 27/05/2022 11:20 am, John S wrote:
> On 5/20/2022 1:48 AM, David Eather wrote: >> On 19/05/2022 8:46 am, John Larkin wrote: >>> On Thu, 19 May 2022 08:06:25 +1000, David Eather >>> <eatREMOVEher@tpg.com.au> wrote: >>> >>>> On 19/05/2022 2:32 am, jlarkin@highlandsniptechnology.com wrote: >>>>> On Wed, 18 May 2022 16:54:32 +0100, Clive Arthur >>>>> <clive@nowaytoday.co.uk> wrote: >>>>> >>>>>> Hi all >>>>>> >>>>>> I have serial data in 14 byte packets on which I'd like to detect and >>>>>> correct errors.&nbsp; Two bit errors would be nice.&nbsp; I can put 2 extra EDC >>>>>> bytes on the end to make a 16 byte packet. >>>>>> >>>>>> I don't have the resources for Reed-Solomon.&nbsp; I could use a 16 bit >>>>>> CRC, >>>>>> these are easy to generate with a small/moderate LUT. >>>>>> >>>>>> In the past, I've used a CRC16 for single bit error detection and >>>>>> correction on a longer packet, but I didn't do the error detection >>>>>> part. >>>>>> &nbsp;&nbsp; Errors were very rare, time was not critical, and I understand >>>>>> that >>>>>> this was simply done by changing each message bit in turn then >>>>>> recalculating the CRC till it all worked out.&nbsp; That's far to slow >>>>>> for my >>>>>> current needs. >>>>>> >>>>>> If I'm lucky, a 16 bit CRC might be able to detect and correct 2 bit >>>>>> errors in 14 bytes (112 * 111 possibilities?), but is there a way of >>>>>> quickly finding out which bits are wrong? >>>>>> >>>>>> Or maybe a completely different approach? This has to be done on the >>>>>> fly, and multi-kilobyte LUTs or thousands of clock cycles are out >>>>>> of the >>>>>> question. >>>>> >>>>> >>>>> Send it three times and compare. >>>>> >>>>> >>>>> >>>> >>>> >>>> you didn't read the 2 byte limit he said he had? The answer is it can't >>>> be done with the constraints he has specified. >>> >>> He specified a packet length limit, but didn't say he couldn't send it >>> multiple times. >>> >>> I'm trying to be helpful, you are trying to be obnoxious. Do whatever >>> you are best at. >>> >> >> I'm being helpful - if he had such a limit on packet size he probably >> has a limit on how much he can send. What he wants is not possible >> with the limits he has described. It is helpful to let him know he has >> to reassess his limits rather than just assume he can do what you want >> - and there are more efficient ways than just send it three times. >> >> you were just being noise. > > And you left your filter at home, eh?
the same as JL did
Reply by John S May 26, 20222022-05-26
On 5/20/2022 1:48 AM, David Eather wrote:
> On 19/05/2022 8:46 am, John Larkin wrote: >> On Thu, 19 May 2022 08:06:25 +1000, David Eather >> <eatREMOVEher@tpg.com.au> wrote: >> >>> On 19/05/2022 2:32 am, jlarkin@highlandsniptechnology.com wrote: >>>> On Wed, 18 May 2022 16:54:32 +0100, Clive Arthur >>>> <clive@nowaytoday.co.uk> wrote: >>>> >>>>> Hi all >>>>> >>>>> I have serial data in 14 byte packets on which I'd like to detect and >>>>> correct errors.&nbsp; Two bit errors would be nice.&nbsp; I can put 2 extra EDC >>>>> bytes on the end to make a 16 byte packet. >>>>> >>>>> I don't have the resources for Reed-Solomon.&nbsp; I could use a 16 bit >>>>> CRC, >>>>> these are easy to generate with a small/moderate LUT. >>>>> >>>>> In the past, I've used a CRC16 for single bit error detection and >>>>> correction on a longer packet, but I didn't do the error detection >>>>> part. >>>>> &nbsp;&nbsp; Errors were very rare, time was not critical, and I understand that >>>>> this was simply done by changing each message bit in turn then >>>>> recalculating the CRC till it all worked out.&nbsp; That's far to slow >>>>> for my >>>>> current needs. >>>>> >>>>> If I'm lucky, a 16 bit CRC might be able to detect and correct 2 bit >>>>> errors in 14 bytes (112 * 111 possibilities?), but is there a way of >>>>> quickly finding out which bits are wrong? >>>>> >>>>> Or maybe a completely different approach? This has to be done on the >>>>> fly, and multi-kilobyte LUTs or thousands of clock cycles are out >>>>> of the >>>>> question. >>>> >>>> >>>> Send it three times and compare. >>>> >>>> >>>> >>> >>> >>> you didn't read the 2 byte limit he said he had? The answer is it can't >>> be done with the constraints he has specified. >> >> He specified a packet length limit, but didn't say he couldn't send it >> multiple times. >> >> I'm trying to be helpful, you are trying to be obnoxious. Do whatever >> you are best at. >> > > I'm being helpful - if he had such a limit on packet size he probably > has a limit on how much he can send. What he wants is not possible with > the limits he has described. It is helpful to let him know he has to > reassess his limits rather than just assume he can do what you want - > and there are more efficient ways than just send it three times. > > you were just being noise.
And you left your filter at home, eh?
Reply by May 24, 20222022-05-24
On Mon, 23 May 2022 21:00:41 -0700, boB <boB@K7IQ.com> wrote:

>On Mon, 23 May 2022 06:49:39 -0700, jlarkin@highlandsniptechnology.com >wrote: > >>On Sun, 22 May 2022 22:54:04 -0700, boB <boB@K7IQ.com> wrote: >> >>>On Sun, 22 May 2022 20:49:08 -0700, jlarkin@highlandsniptechnology.com >>>wrote: >>> >>>>On Sun, 22 May 2022 19:28:39 -0700, Don Y >>>><blockedofcourse@foo.invalid> wrote: >>>> >>>>>On 5/19/2022 12:24 PM, whit3rd wrote: >>>>>> On Thursday, May 19, 2022 at 8:03:55 AM UTC-7, jla...@highlandsniptechnology.com wrote: >>>>>>> On Thu, 19 May 2022 07:40:45 -0700 (PDT), Lasse Langwadt Christensen >>>>>>> <lang...@fonz.dk> wrote: >>>>>>> >>>>>>>> torsdag den 19. maj 2022 kl. 16.36.23 UTC+2 skrev jla...@highlandsniptechnology.com: >>>>>>>>> On Thu, 19 May 2022 12:58:33 -0000 (UTC), Keegan Major >>>>>> >>>>>>> Of course, some people are hostile to ideas. Their career path is more >>>>>>> McDonalds than electronic design. >>>>>> >>>>>> Again with the goofy personality theories! Everyone is hostile to ideas >>>>>> for a few minutes in the evening, when it's time to sleep. >>>>>> >>>>>> That's normal, and has nothing to do with a career path. >>>>> >>>>>That's *cranky*. I have little patience for distractions (of any kind) >>>>>when I'm over tired (and focused on getting things in order so I can >>>>>*rest*) or "overloaded" -- and need to get things off my plate so I can >>>>>concentrate on something "new". >>>>> >>>>>> No sane conscious mind is 'hostile to ideas' in any more general sense; that >>>>>> would be pathological, like being hostile to one's own body parts. >>>>> >>>>>People aren't hostile to ideas (JL sees *everything* as some aspect of >>>>>hostility; an entirely passive-aggressive outlook on life). >>>> >>>>Not at all. I'm cheerful and helpful. But there are a lot of nasty >>>>people here who don't design electronics. >>> >>>You sure got that right ! >>> >>>boB >>> >>> >>> >> >>Playing with circuits is fun. Endless ritual squabbling is boring and >>bad for you. So why do they do it here? > >Not sure ? > >This may be a place where they can "identify" somehow. Kind of like >flat earthers and those who follow an alternative existence. > >They feel that they "belong" somehow.
The subject here is electronics. The old hens don't belong.
> >If I were a psychologist, I might be able to find a name for SED. > >boB > >
If people want to discuss their feelings, they should go to Facebook or Grindr. -- Anybody can count to one. - Robert Widlar
Reply by boB May 24, 20222022-05-24
On Mon, 23 May 2022 06:49:39 -0700, jlarkin@highlandsniptechnology.com
wrote:

>On Sun, 22 May 2022 22:54:04 -0700, boB <boB@K7IQ.com> wrote: > >>On Sun, 22 May 2022 20:49:08 -0700, jlarkin@highlandsniptechnology.com >>wrote: >> >>>On Sun, 22 May 2022 19:28:39 -0700, Don Y >>><blockedofcourse@foo.invalid> wrote: >>> >>>>On 5/19/2022 12:24 PM, whit3rd wrote: >>>>> On Thursday, May 19, 2022 at 8:03:55 AM UTC-7, jla...@highlandsniptechnology.com wrote: >>>>>> On Thu, 19 May 2022 07:40:45 -0700 (PDT), Lasse Langwadt Christensen >>>>>> <lang...@fonz.dk> wrote: >>>>>> >>>>>>> torsdag den 19. maj 2022 kl. 16.36.23 UTC+2 skrev jla...@highlandsniptechnology.com: >>>>>>>> On Thu, 19 May 2022 12:58:33 -0000 (UTC), Keegan Major >>>>> >>>>>> Of course, some people are hostile to ideas. Their career path is more >>>>>> McDonalds than electronic design. >>>>> >>>>> Again with the goofy personality theories! Everyone is hostile to ideas >>>>> for a few minutes in the evening, when it's time to sleep. >>>>> >>>>> That's normal, and has nothing to do with a career path. >>>> >>>>That's *cranky*. I have little patience for distractions (of any kind) >>>>when I'm over tired (and focused on getting things in order so I can >>>>*rest*) or "overloaded" -- and need to get things off my plate so I can >>>>concentrate on something "new". >>>> >>>>> No sane conscious mind is 'hostile to ideas' in any more general sense; that >>>>> would be pathological, like being hostile to one's own body parts. >>>> >>>>People aren't hostile to ideas (JL sees *everything* as some aspect of >>>>hostility; an entirely passive-aggressive outlook on life). >>> >>>Not at all. I'm cheerful and helpful. But there are a lot of nasty >>>people here who don't design electronics. >> >>You sure got that right ! >> >>boB >> >> >> > >Playing with circuits is fun. Endless ritual squabbling is boring and >bad for you. So why do they do it here?
Not sure ? This may be a place where they can "identify" somehow. Kind of like flat earthers and those who follow an alternative existence. They feel that they "belong" somehow. If I were a psychologist, I might be able to find a name for SED. boB
Reply by May 23, 20222022-05-23
On Sun, 22 May 2022 22:54:04 -0700, boB <boB@K7IQ.com> wrote:

>On Sun, 22 May 2022 20:49:08 -0700, jlarkin@highlandsniptechnology.com >wrote: > >>On Sun, 22 May 2022 19:28:39 -0700, Don Y >><blockedofcourse@foo.invalid> wrote: >> >>>On 5/19/2022 12:24 PM, whit3rd wrote: >>>> On Thursday, May 19, 2022 at 8:03:55 AM UTC-7, jla...@highlandsniptechnology.com wrote: >>>>> On Thu, 19 May 2022 07:40:45 -0700 (PDT), Lasse Langwadt Christensen >>>>> <lang...@fonz.dk> wrote: >>>>> >>>>>> torsdag den 19. maj 2022 kl. 16.36.23 UTC+2 skrev jla...@highlandsniptechnology.com: >>>>>>> On Thu, 19 May 2022 12:58:33 -0000 (UTC), Keegan Major >>>> >>>>> Of course, some people are hostile to ideas. Their career path is more >>>>> McDonalds than electronic design. >>>> >>>> Again with the goofy personality theories! Everyone is hostile to ideas >>>> for a few minutes in the evening, when it's time to sleep. >>>> >>>> That's normal, and has nothing to do with a career path. >>> >>>That's *cranky*. I have little patience for distractions (of any kind) >>>when I'm over tired (and focused on getting things in order so I can >>>*rest*) or "overloaded" -- and need to get things off my plate so I can >>>concentrate on something "new". >>> >>>> No sane conscious mind is 'hostile to ideas' in any more general sense; that >>>> would be pathological, like being hostile to one's own body parts. >>> >>>People aren't hostile to ideas (JL sees *everything* as some aspect of >>>hostility; an entirely passive-aggressive outlook on life). >> >>Not at all. I'm cheerful and helpful. But there are a lot of nasty >>people here who don't design electronics. > >You sure got that right ! > >boB > > >
Playing with circuits is fun. Endless ritual squabbling is boring and bad for you. So why do they do it here? -- Anybody can count to one. - Robert Widlar
Reply by boB May 23, 20222022-05-23
On Sun, 22 May 2022 20:49:08 -0700, jlarkin@highlandsniptechnology.com
wrote:

>On Sun, 22 May 2022 19:28:39 -0700, Don Y ><blockedofcourse@foo.invalid> wrote: > >>On 5/19/2022 12:24 PM, whit3rd wrote: >>> On Thursday, May 19, 2022 at 8:03:55 AM UTC-7, jla...@highlandsniptechnology.com wrote: >>>> On Thu, 19 May 2022 07:40:45 -0700 (PDT), Lasse Langwadt Christensen >>>> <lang...@fonz.dk> wrote: >>>> >>>>> torsdag den 19. maj 2022 kl. 16.36.23 UTC+2 skrev jla...@highlandsniptechnology.com: >>>>>> On Thu, 19 May 2022 12:58:33 -0000 (UTC), Keegan Major >>> >>>> Of course, some people are hostile to ideas. Their career path is more >>>> McDonalds than electronic design. >>> >>> Again with the goofy personality theories! Everyone is hostile to ideas >>> for a few minutes in the evening, when it's time to sleep. >>> >>> That's normal, and has nothing to do with a career path. >> >>That's *cranky*. I have little patience for distractions (of any kind) >>when I'm over tired (and focused on getting things in order so I can >>*rest*) or "overloaded" -- and need to get things off my plate so I can >>concentrate on something "new". >> >>> No sane conscious mind is 'hostile to ideas' in any more general sense; that >>> would be pathological, like being hostile to one's own body parts. >> >>People aren't hostile to ideas (JL sees *everything* as some aspect of >>hostility; an entirely passive-aggressive outlook on life). > >Not at all. I'm cheerful and helpful. But there are a lot of nasty >people here who don't design electronics.
You sure got that right ! boB
Reply by May 23, 20222022-05-23
On Sun, 22 May 2022 19:28:39 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:

>On 5/19/2022 12:24 PM, whit3rd wrote: >> On Thursday, May 19, 2022 at 8:03:55 AM UTC-7, jla...@highlandsniptechnology.com wrote: >>> On Thu, 19 May 2022 07:40:45 -0700 (PDT), Lasse Langwadt Christensen >>> <lang...@fonz.dk> wrote: >>> >>>> torsdag den 19. maj 2022 kl. 16.36.23 UTC+2 skrev jla...@highlandsniptechnology.com: >>>>> On Thu, 19 May 2022 12:58:33 -0000 (UTC), Keegan Major >> >>> Of course, some people are hostile to ideas. Their career path is more >>> McDonalds than electronic design. >> >> Again with the goofy personality theories! Everyone is hostile to ideas >> for a few minutes in the evening, when it's time to sleep. >> >> That's normal, and has nothing to do with a career path. > >That's *cranky*. I have little patience for distractions (of any kind) >when I'm over tired (and focused on getting things in order so I can >*rest*) or "overloaded" -- and need to get things off my plate so I can >concentrate on something "new". > >> No sane conscious mind is 'hostile to ideas' in any more general sense; that >> would be pathological, like being hostile to one's own body parts. > >People aren't hostile to ideas (JL sees *everything* as some aspect of >hostility; an entirely passive-aggressive outlook on life).
Not at all. I'm cheerful and helpful. But there are a lot of nasty people here who don't design electronics. -- Anybody can count to one. - Robert Widlar
Reply by Don Y May 22, 20222022-05-22
On 5/19/2022 12:24 PM, whit3rd wrote:
> On Thursday, May 19, 2022 at 8:03:55 AM UTC-7, jla...@highlandsniptechnology.com wrote: >> On Thu, 19 May 2022 07:40:45 -0700 (PDT), Lasse Langwadt Christensen >> <lang...@fonz.dk> wrote: >> >>> torsdag den 19. maj 2022 kl. 16.36.23 UTC+2 skrev jla...@highlandsniptechnology.com: >>>> On Thu, 19 May 2022 12:58:33 -0000 (UTC), Keegan Major > >> Of course, some people are hostile to ideas. Their career path is more >> McDonalds than electronic design. > > Again with the goofy personality theories! Everyone is hostile to ideas > for a few minutes in the evening, when it's time to sleep. > > That's normal, and has nothing to do with a career path.
That's *cranky*. I have little patience for distractions (of any kind) when I'm over tired (and focused on getting things in order so I can *rest*) or "overloaded" -- and need to get things off my plate so I can concentrate on something "new".
> No sane conscious mind is 'hostile to ideas' in any more general sense; that > would be pathological, like being hostile to one's own body parts.
People aren't hostile to ideas (JL sees *everything* as some aspect of hostility; an entirely passive-aggressive outlook on life). But, people can be resistant to the *consequences* of ideas. Direct or otherwise. NIH figures big in engineering. Folks always want to think their PAST accomplishment is somehow the epitome of thinking on that subject. This is likely some reflection on their own ego as well as a manifestation of "laziness" -- they aren't really interested in solving a problem again, even if *better*! And, engineering is a field where one is quickly obsolete. Especially if too narrow a focus in your endeavors. I had a stick-in-the-mud fight tooth-and-nail against replacing HIS decade-old analog control system with a digital one. Despite the fact that customers weren't buying it anymore AND sales of the "controlled equipment" (7 figures) were being lost because of this "antiquated offering". Another old-timer fought to preserve a part numbering system that, ages ago (when fewer parts were in inventory) would allow him to fabricate a "close approximation" to a desired part number using a paper cheat sheet he kept in his wallet. ("And what do we do when you're on vacation? Or, RETIRE??!") Another *principal* argued that developers should use octal notation to specify *opcodes* (!) using a similar "pocket assembler". ("Um, you know, there are tools that eliminate the need for doing this sort of thing. Just like there are tools that allow us to travel great distances without wearing out our SHOES!") Or, clinging to old ideas because they were patent worthy -- ten years ago! <rolls eyes> Despite the fact that your competitors have all found BETTER ways to do the same thing! All examples of the "that's how we USED to do it" mindset. ("I *built* this company using that technique!" "Yeah, and it hasn't *grown* in years!") All examples of people keeping their companies tied to the past and closing off opportunities to advance. I find email to be the single most effective tool in the design process: - It is self-documenting. - It supports participants at widely different locations/timezones - It allows the recipients time to digest the material presented. - It allows them time to formulate and revise their response. I know many folks who are lousy "thinking on their feet". But, given time, have tremendously valuable insights. - It is non-confrontational. Face to face *meetings* (not a one-on-one by the water cooler) have undercurrents, especially in small companies where folks may have agendas or jockey to get in the boss's good favor or risk "bucking the system". - It inherently dampens any "unbridled enthusiasm" that may be based in emotion and not reason. - No "voice" can overpower a conversation. - There's no "audience"; come as you are! - There's no implied (polite society) need to respond to every utterance. You can just let an idea die, "gracefully". - There's no issue of "face" - The Cc: list can change from one message to the next. To bring someone into the conversation, you just have to add their name to the Cc/Bcc line. - Participants can drop out of the conversation at will (imagine getting up and excusing yourself from a meeting and NOT being noticed for doing so!) - You can adjust your recipients to subsets of the group without offending those not involved *or* distracting from their ongoing conversations. - You can cut-and-paste bits of the conversation into your design specification/requirements document/manual using words that others have already chosen The biggest downside to email is a consequence of all of these features: the elapsed time involved. But, if you think you can "create on demand" or "within a specific timeframe", you are likely going to get only incremental changes to ideas. It takes time to stew on issues before you can formulate GOOD solutions. [I find the shower to be the best "facilitator"; no visual or audible distractions, comfortable warmth, etc. I'm free to "just imagine" solutions without having to deal with other people, pen&paper, etc.] But, if you're just working on small/simple problems, you can likely hammer out *a* solution in short order.
Reply by whit3rd May 22, 20222022-05-22
On Sunday, May 22, 2022 at 4:49:27 PM UTC-7, jla...@highlandsniptechnology.com wrote:

> Arguing, to me, implies a classic debate style, where the objective of > every player is to be right and to prove their opponents wrong. It's > not quarreling but is still emotional competition... the goal being to > win.
The Plato-era 'classic' works on argument call that 'gotta-win' variant sophistry, and refuted the validity of sophistical arguments while supporting logical arguments. Debate is contrivance, a game lawyers play in their effort to become better advocates; it isn't a productive exercise, nor does it attempt truth-seeking.
> Brainstorming is a team-less sport played for fun, where the objective > is to invent ideas together.
The psychology faculty taught me otherwise; the domination of group thinking by loud voices was hurting productivity, and they built, and tested, formal rules for brainstorming as a technical fix for that flaw. <https://en.wikipedia.org/wiki/Brainstorming>