eqn =
Résultats pour
The int function in the Symbolic Toolbox has a hold/release functionality wherein the expression can be held to delay evaluation
syms x I
eqn = I == int(x,x,'Hold',true)
which allows one to show the integral, and then use release to show the result
release(eqn)
Maybe it would be nice to be able to hold/release any symbolic expression to delay the engine from doing evaluations/simplifications that it typically does. For example:
x*(x+1)/x, sin(sym(pi)/3)
If I'm trying to show a sequence of steps to develop a result, maybe I want to explicitly keep the x/x in the first case and then say "now the x in the numerator and denominator cancel and the result is ..." followed by the release command to get the final result.
Perhaps held expressions could even be nested to show a sequence of results upon subsequent releases.
Held expressions might be subject to other limitations, like maybe they can't be fplotted.
Seems like such a capability might not be useful for problem solving, but might be useful for exposition, instruction, etc.
I am using a micro:bit device with ESP8266 for a IOT project, but cannot connect thingspeak recently.
The conncection is unstable, I can hardly connect to thingspeak for days, somehow it works last night for 30 mins and then it fails.
The program does not change and I have included a 25 sec delayed between each data sending.
Please advice why and how to fix it. Thank you.
Christmas season is underway at my house:
(Sorry - the ornament is not available at the MathWorks Merch Shop -- I made it with a 3-D printer.)
I am using the ELECFREAKS IOT:bit Expansion Board with micro:bit to record data, it worked normally but in this week I tested again, and discover no data is uploaded to the channel ie.no entries in channel. The code in makecode are the same as before and the wifi is work, I cannot find the reason that cause this failure.
I am using the free option with 4 channels available. I do not have any channels listed, but when I want to create a new channel it gives me an error massage to say that I have used up my 4 channels and need to purchase units to create additional channels.
Is it possible to differenciate the input, output and in-between wires by colors?
I was curious to startup your new AI Chat playground.
The first screen that popped up made the statement:
"Please keep in mind that AI sometimes writes code and text that seems accurate, but isnt"
Can someone elaborate on what exactly this means with respect to your AI Chat playground integration with the Matlab tools?
Are there any accuracy metrics for this integration?
Hello
I have 3 devices (IOT board using SIM7600 module) sending one value to Thingsspeak. Have been working just fine a couple of years. However 14/11-24 I receive http error code 406 for all 3 devices.
The http get is working just fine when testing directly in the browser (https://api.thingspeak.com/update?api_key=xxxxx&field1=33), the server return the entrie number.
However, when running the same address via SIM7600 I receive - +HTTPACTION: 0,406,0
Any tips for the 406 error code?
Hello, I am wondering why I have over 12000 messages (writes)per day to a channel which I only update all 8 fields every 20 minutes. Or are these statistic timely delayed? Since testing I might have more writes, but now with my ready weather station only every 20 minutes my data will be updated. Wetterbox Channel ID: 2391212 Access: Public Can you explain this to me? Thank you for your help. Regards, Julian
It would be nice to have a function to shade between two curves. This is a common question asked on Answers and there are some File Exchange entries on it but it's such a common thing to want to do I think there should be a built in function for it. I'm thinking of something like
plotsWithShading(x1, y1, 'r-', x2, y2, 'b-', 'ShadingColor', [.7, .5, .3], 'Opacity', 0.5);
So we can specify the coordinates of the two curves, and the shading color to be used, and its opacity, and it would shade the region between the two curves where the x ranges overlap. Other options should also be accepted, like line with, line style, markers or not, etc. Perhaps all those options could be put into a structure as fields, like
plotsWithShading(x1, y1, options1, x2, y2, options2, 'ShadingColor', [.7, .5, .3], 'Opacity', 0.5);
the shading options could also (optionally) be a structure. I know it can be done with a series of other functions like patch or fill, but it's kind of tricky and not obvious as we can see from the number of questions about how to do it.
Does anyone else think this would be a convenient function to add?
In the past two years, large language models have brought us significant changes, leading to the emergence of programming tools such as GitHub Copilot, Tabnine, Kite, CodeGPT, Replit, Cursor, and many others. Most of these tools support code writing by providing auto-completion, prompts, and suggestions, and they can be easily integrated with various IDEs.
As far as I know, aside from the MATLAB-VSCode/MatGPT plugin, MATLAB lacks such AI assistant plugins for its native MATLAB-Desktop, although it can leverage other third-party plugins for intelligent programming assistance. There is hope for a native tool of this kind to be built-in.
I am considering to upgrade to HOME license. Does the HOME license provides more widgets (including a text message widget), in addition to the 4 basic widgets in the FREE version?
I know we have all been in that all-too-common situation of needing to inefficiently identify prime numbers using only a regular expression... and now Matt Parker from Standup Maths helpfully released a YouTube video entitled "How on Earth does ^.?$|^(..+?)\1+$ produce primes?" in which he explains a simple regular expression (aka Halloween incantation) which matches composite numbers:
Here is my first attempt using MATLAB and Matt Parker's example values:
fnh = @(n) isempty(regexp(repelem('*',n),'^.?$|^(..+?)\1+$','emptymatch'));
fnh(13)
fnh(15)
fnh(101)
fnh(1000)
Feel free to try/modify the incantation yourself. Happy Halloween!
Watch episodes 5-7 for the new stuff, but the whole series is really great.
Hi,
I don't know why really. Why is there seems a difference between daily average that calculated with .csv file that has exported directly from the channel.
and calculation with the ThingSpeak Daily Average API, there is a lot of difference at the moment.
Why does this happens, and how should I fix this issue?
Attached image file is daily average that has been retrived through the API,
And attached excel file is raw data from the channel.
Thank you.
初カキコ…ども… 俺みたいな中年で深夜にMATLAB見てる腐れ野郎、 他に、いますかっていねーか、はは
今日のSNSの会話 あの流行りの曲かっこいい とか あの 服ほしい とか ま、それが普通ですわな
かたや俺は電子の砂漠でfor文無くして、呟くんすわ
it'a true wolrd．狂ってる？それ、誉め 言葉ね。
好きなtoolbox Signal Processing Toolbox
尊敬する人間 Answersの海外ニキ（学校の課題質問はNO）
なんつってる間に4時っすよ(笑) あ～あ、休日の辛いとこね、これ
-----------
ディスカッションに記事を書いたら謎の力によって消えたっぽいので、性懲りもなくだらだら書いていこうと思います。前書いた内容忘れたからテキトーに書きます。
救いたいんですよ、Centralを(倒置法)
いっぬはMATLAB Answersに育てられてキャリアを積んできたんですよ。暇な時間を見つけてはAnswersで回答して承認欲求を満たしてきたんです。わかんない質問に対しては別の人が回答したのを学び、応用してバッジもらったりしちゃったりしてね。
そんな思い出の大事な1ピースを担うMATLAB Centralが、いま、苦境に立たされている。僕はMATLAB Centralを救いたい。
最悪、救うことが出来なくともCentralと一緒に死にたい。Centralがコミュニティを閉じるのに合わせて、僕の人生の幕も閉じたい。MATLABメンヘラと呼ばれても構わない。MATLABメンヘラこそ、MATLABに対する愛の証なのだ。MATLABメンヘラと呼ばれても、僕は強く生きる。むしろ、誇りに思うだろう。
こうしてMATLABメンヘラへの思いの丈を精一杯綴った今、僕はこう思う。
MATLABメンヘラって何？
なぜ苦境に立っているのか？
生成AIである。Hernia Babyは激怒した。必ず、かの「もうこれでいいじゃん」の王を除かなければならぬと決意した。Hernia BabyにはAIの仕組みがわからぬ。Hernia Babyは、会社の犬畜生である。マネージャが笛を吹き、エナドリと遊んで暮して来た。けれどもネットmemeに対しては、人一倍に敏感であった。
風の噂によるとMATLAB Answersの質問数も微妙に減少傾向にあるそうな。
確かにTwitter(現X)でもAnswers botの呟き減ったような…。
ゆ、許せんぞ生成AI…！
MATLAB Centralは日本では流行ってない？
そもそもCentralって日本じゃあまりアクセスされてないんじゃなイカ？
だってどうやってここにたどり着けばいいかわかんねえもん！(暴言)
MATLABのHPにはないから一回コミュニティのプロファイル入って…
やっと表示される。気づかんって！
MATLAB Centralは無料で学べる宝物庫
とはいえ本当にオススメなんです。
どんなのがあるかさらっと紹介していきます。
ここは短い文章で問題を解くコードを書き上げるところ。
多様な分野を実践的に学ぶことができるし、何より他人のコードも見ることができる。
たまにそんなのありかよ～って回答もあるけどいい訓練になる。
ただ英語の問題見たらさ~ 悪い やっぱつれぇわ…
我らがアイドルmichioニキやJiro氏が新機能について紹介なんかもしてくれてる。
なんだかんだTwitter(現X)で紹介しちゃってるから、見るのさぼったり…ｹﾞﾌﾝｹﾞﾌﾝ!
定期的に開催される。
プライズも貰えたりするし、何よりめっちゃ面白い作品を皆が書いてくる。
p=pi;
l = 5e3;
m = 0:l;
[u,v]=meshgrid(10*m/l*p,2*m/l*p);
c=cos(v/2);
s=sin(v);
e=1-exp(u/(6*p));
surf(2*e.*cos(u).*c.^2,-e*2.*sin(u).*c.^2,1-exp(u/(3.75*p))-s+exp(u/(5.5*p)).*s,'FaceColor','#a47a43','EdgeAlpha',0.02)
axis equal off
A=7.3;
zlim([-A 0])
view([-12 23])
set(gcf,'Color','#d2b071')
過去の事は水に流してくれないか？
toolboxにない自作関数とかを無料で皆が公開してるところ。
MATLABのアドオンからだと関数をそのままインストール出来たりする。
だいたいの答えはここにある。質問する前にググれば出てくる。
躓いて調べると過去に書いてあった自分の回答に助けられたりもする。
for文で回答すると一定数の海外ニキたちが
と絡んでくる。
Answersがバキバキ回答する場であるのに対して、ここでは好きなことを呟いていいらしい。最近できたっぽい。全然知らんかった。海外では「こんな機能欲しくね？」とかけっこう人気っぽい。
日本人が書いてないから僕がこんなクソスレ書いてるわけ┐(´д｀)┌ﾔﾚﾔﾚ
まとめ
いかがだったでしょうか？このようにCentralは学びとして非常に有効な場所なのであります。インプットもいいけど是非アウトプットしてみましょう。コミュニティはアカウントさえ持ってたら無料でやれるんでね。
皆はどうやってMATLAB/Simulinkを学んだか、良ければ返信でクソレスしてくれると嬉しいです。特にSimulinkはマジでな～んにもわからん。MathWorksさんode45とかソルバーの説明ここでしてくれ。
後、ディスカッション一時保存機能つけてほしい。
最後に
Centralより先に、俺を救え
参考：ミスタードーナツを救え
My Licensed avvount has expired. When I go to my expired license page, I select "Revert To Free Account", I get the following message:
Only administrators of this license are allowed to renew units on this ThingSpeak license. If you want to continue to collect data in your ThingSpeak channels, contact your license administrator.
Aren't I the license administrator? or do I need to contact someone at Thingspeak/MathWorks?
