1922760350154212639070
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How can we use roughness in an effective context to identify large primes? I can quickly think of quite a few examples where we might do so. Again, remember I will be looking for primes with not just hundreds of decimal digits, or even only a few thousand digits. The eventual target is higher than that. Forget about targets for now though, as this is a journey, and what matters in this journey is what we may learn along the way.
I think the most obvious way to employ roughness is in a search for twin primes. Though not yet proven, the twin prime conjecture:
If it is true, it tells us there are infinitely many twin prime pairs. A twin prime pair is two integers with a separation of 2, such that both of them are prime. We can find quite a few of them at first, as we have {3,5}, {5,7}, {11,13}, etc. But there is only ONE pair of integers with a spacing of 1, such that both of them are prime. That is the pair {2,3}. And since primes are less and less common as we go further out, possibly there are only a finite number of twins with a spacing of exactly 2? Anyway, while I'm fairly sure the twin prime conjecture will one day be shown to be true, it can still be interesting to search for larger and larger twin prime pairs. The largest such known pair at the moment is
2996863034895*2^1290000 +/- 1
This is a pair with 388342 decimal digits. And while seriously large, it is still in range of large integers we can work with in MATLAB, though certainly not in double precision. In my own personal work on my own computer, I've done prime testing on integers (in MATLAB) with considerably more than 100,000 decimal digits.
But, again you may ask, just how does roughness help us here? In fact, this application of roughness is not new with me. You might want to read about tools like NewPGen {https://t5k.org/programs/NewPGen/} which sieves out numbers known to be composite, before any direct tests for primality are performed.
Before we even try to talk about numbers with thousands or hundreds of thousands of decimal digits, look at 6=2*3. You might observe
isprime([-1,1] + 6)
shows that both 5 and 7 are prime. This should not be a surprise, but think about what happens, about why it generated a twin prime pair. 6 is divisible by both 2 and 3, so neither 5 or 7 can possibly be divisible by either small prime as they are one more or one less than a multiple of both 2 and 3. We can try this again, pushing the limits just a bit.
isprime([-1,1] + 2*3*5)
That is again interesting. 30=2*3*5 is evenly divisible by 2, 3, and 5. The result is both 29 and 31 are prime, because adding 1 or subtracting 1 from a multiple of 2, 3, or 5 will always result in a number that is not divisible by any of those small primes. The next larger prime after 5 is 7, but it cannot be a factor of 29 or 31, since it is greater than both sqrt(29) and sqrt(31).
We have quite efficiently found another twin prime pair. Can we take this a step further? 210=2*3*5*7 is the smallest such highly composite number that is divisible by all primes up to 7. Can we use the same trick once more?
isprime([-1,1] + 2*3*5*7)
And here the trick fails, because 209=11*19 is not in fact prime. However, can we use the large twin prime trick we saw before? Consider numbers of the form [-1,1]+a*210, where a is itself some small integer?
a = 2;
isprime([-1,1] + a*2*3*5*7)
I did not need to look far, only out to a=2, because both 419 and 421 are prime. You might argue we have formed a twin prime "factory", of sorts. Next, I'll go out as far as the product of all primes not exceeding 60. This is a number with 22 decimal digits, already too large to represent as a double, or even as uint64.
prod(sym(primes(60)))
a = find(all(isprime([-1;1] + prod(sym(primes(60)))*(1:100)),1))
That easily identifies 3 such twin prime pairs, each of which has roughly 23 decimal digits, each of which have the form a*1922760350154212639070+/-1. The twin prime factory is still working well. Going further out to integers with 37 decimal digits, we can easily find two more such pairs that employ the product of all primes not exceeding 100.
prod(sym(primes(100)))
a = find(all(isprime([-1;1] + prod(sym(primes(100)))*(1:100)),1))
This is in fact an efficient way of identifying large twin prime pairs, because it chooses a massively composite number as the product of many distinct small primes. Adding or subtracting 1 from such a number will result always in a rough number, not divisible by any of the primes employed. With a little more CPU time expended, now working with numbers with over 1000 decimal digits, I will claim this next pair forms a twin prime pair, and is the smallest such pair we can generate in this way from the product of the primes not exceeding 2500.
isprime(7826*prod(sym(primes(2500))) + [-1 1])
ans =
logical
1
Unfortunately, 1000 decimal digits is at or near the limit of what the sym/isprime tool can do for us. It does beg the question, asking if there are alternatives to the sym/isprime tool, as an isProbablePrime test, usually based on Miller-Rabin is often employed. But this is gist for yet another set of posts.
Anyway, I've done a search for primes of the form
a*prod(sym(primes(10000))) +/- 1
having gone out as far as a = 600000, with no success as of yet. (My estimate is I will find a pair by the time I get near 5e6 for a.) Anyway, if others can find a better way to search for large twin primes in MATLAB, or if you know of a larger twin prime pair of this extended form, feel free to chime in.
My next post shows how to use GCD in a very nice way to identify roughness, on a large scale.
What is a rough number? What can they be used for? Today I'll take you down a journey into the land of prime numbers (in MATLAB). But remember that a journey is not always about your destination, but about what you learn along the way. And so, while this will be all about primes, and specifically large primes, before we get there we need some background. That will start with rough numbers.
Rough numbers are what I would describe as wannabe primes. Almost primes, and even sometimes prime, but often not prime. They could've been prime, but may not quite make it to the top. (If you are thinking of Marlon Brando here, telling us he "could've been a contender", you are on the right track.)
Mathematically, we could call a number k-rough if it is evenly divisible by no prime smaller than k. (Some authors will use the term k-rough to denote a number where the smallest prime factor is GREATER than k. The difference here is a minor one, and inconsequential for my purposes.) And there are also smooth numbers, numerical antagonists to the rough ones, those numbers with only small prime factors. They are not relevant to the topic today, even though smooth numbers are terribly valuable tools in mathematics. Please forward my apologies to the smooth numbers.
Have you seen rough numbers in use before? Probably so, at least if you ever learned about the sieve of Eratosthenes for prime numbers, though probably the concept of roughness was never explicitly discussed at the time. The sieve is simple. Suppose you wanted a list of all primes less than 100? (Without using the primes function itself.)
% simple sieve of Eratosthenes
Nmax = 100;
N = true(1,Nmax); % A boolean vector which when done, will indicate primes
N(1) = false; % 1 is not a prime by definition
nextP = find(N,1,'first'); % the first prime is 2
while nextP <= sqrt(Nmax)
% flag multiples of nextP as not prime
N(nextP*nextP:nextP:end) = false;
% find the first element after nextP that remains true
nextP = nextP + find(N(nextP+1:end),1,'first');
end
primeList = find(N)
Indeed, that is the set of all 25 primes not exceeding 100. If you think about how the sieve worked, it first found 2 is prime. Then it discarded all integer multiples of 2. The first element after 2 that remains as true is 3. 3 is of course the second prime. At each pass through the loop, the true elements that remain correspond to numbers which are becoming more and more rough. By the time we have eliminated all multiples of 2, 3, 5, and finally 7, everything else that remains below 100 must be prime! The next prime on the list we would find is 11, but we have already removed all multiples of 11 that do not exceed 100, since 11^2=121. For example, 77 is 11*7, but we already removed it, because 77 is a multiple of 7.
Such a simple sieve to find primes is great for small primes. However is not remotely useful in terms of finding primes with many thousands or even millions of decimal digits. And that is where I want to go, eventually. So how might we use roughness in a useful way? You can think of roughness as a way to increase the relative density of primes. That is, all primes are rough numbers. In fact, they are maximally rough. But not all rough numbers are primes. We might think of roughness as a necessary, but not sufficient condition to be prime.
How many primes lie in the interval [1e6,2e6]?
numel(primes(2e6)) - numel(primes(1e6))
There are 70435 primes greater than 1e6, but less than 2e6. Given there are 1 million natural numbers in that set, roughly 7% of those numbers were prime. Next, how many 100-rough numbers lie in that same interval?
N = (1e6:2e6)';
roughInd = all(mod(N,primes(100)) > 0,2);
sum(roughInd)
That is, there are 120571 100-rough numbers in that interval, but all those 70435 primes form a subset of the 100-rough numbers. What does this tell us? Of the 1 million numbers in that interval, approximately 12% of them were 100-rough, but 58% of the rough set were prime.
The point being, if we can efficiently identify a number as being rough, then we can substantially increase the chance it is also prime. Roughness in this sense is a prime densifier. (Is that even a word? It is now.) If we can reduce the number of times we need to perform an explicit isprime test, that will gain greatly because a direct test for primality is often quite costly in CPU time, at least on really large numbers.
In my next post, I'll show some ways we can employ rough numbers to look for some large primes.
tiledlayout(4,1);
% Plot "L" (y = 1/(x+1), for x > -1)
x = linspace(-0.9, 2, 100); % Avoid x = -1 (undefined)
y =1 ./ (x+1) ;
nexttile;
plot(x, y, 'r', 'LineWidth', 2);
xlim([-10,10])
% Plot "O" (x^2 + y^2 = 9)
theta = linspace(0, 2*pi, 100);
x = 3 * cos(theta);
y = 3 * sin(theta);
nexttile;
plot(x, y, 'r', 'LineWidth', 2);
axis equal;
% Plot "V" (y = -2|x|)
x = linspace(-1, 1, 100);
y = 2 * abs(x);
nexttile;
plot(x, y, 'r', 'LineWidth', 2);
axis equal;
% Plot "E" (x = -3 |sin(y)|)
y = linspace(-pi, pi, 100);
x = -3 * abs(sin(y));
nexttile;
plot(x, y, 'r', 'LineWidth', 2);
axis equal;
I've been trying this problem a lot of time and i don't understand why my solution doesnt't work.
In 4 tests i get the error Assertion failed but when i run the code myself i get the diag and antidiag correctly.
function [diag_elements, antidg_elements] = your_fcn_name(x)
[m, n] = size(x);
% Inicializar los vectores de la diagonal y la anti-diagonal
diag_elements = zeros(1, min(m, n));
antidg_elements = zeros(1, min(m, n));
% Extraer los elementos de la diagonal
for i = 1:min(m, n)
diag_elements(i) = x(i, i);
end
% Extraer los elementos de la anti-diagonal
for i = 1:min(m, n)
antidg_elements(i) = x(m-i+1, i);
end
end
Check out the result of "emoji matrix" multiplication below.
- vector multiply vector:
a = ["😁","😁","😁"]
b = ["😂";
"😂"
"😂"]
c = a*b
d = b*a
- matrix multiply matrix:
matrix1 = [
"😀", "😃";
"😄", "😁"]
matrix2 = [
"😆", "😅";
"😂", "🤣"]
resutl = matrix1*matrix2
enjoy yourself!
For Valentine's day this year I tried to do something a little more than just the usual 'Here's some MATLAB code that draws a picture of a heart' and focus on how to share MATLAB code. TL;DR, here's my advice
- Put the code on GitHub. (Allows people to access and collaborate on your code)
- Set up 'Open in MATLAB Online' in your GitHub repo (Allows people to easily run it)
I used code by @Zhaoxu Liu / slandarer and others to demonstrate. I think that those two steps are the most impactful in that they get you from zero to one but If I were to offer some more advice for research code it would be
3. Connect the GitHub repo to File Exchange (Allows MATLAB users to easily find it in-product).
4. Get a Digitial Object Identifier (DOI) using something like Zenodo. (Allows people to more easily cite your code)
There is still a lot more you can do of course but if everyone did this for any MATLAB code relating to a research paper, we'd be in a better place I think.
Here's the article: On love and research software: Sharing code with your Valentine » The MATLAB Blog - MATLAB & Simulink
What do you think?
I got thoroughly nerd-sniped by this xkcd, leading me to wonder if you can use MATLAB to figure out the dice roll for any given (rational) probability. Well, obviously you can. The question is how. Answer: lots of permutation calculations and convolutions.
In the original xkcd, the situation described by the player has a probability of 2/9. Looking up the plot, row 2 column 9, shows that you need 16 or greater on (from the legend) 1d4+3d6, just as claimed.
If you missed the bit about convolutions, this is a super-neat trick
[v,c] = dicedist([4 6 6 6]);
bar(v,c)
% Probability distribution of dice given by d
function [vals,counts] = dicedist(d)
% d is a vector of number of sides
n = numel(d); % number of dice
% Use convolution to count the number of ways to get each roll value
counts = 1;
for k = 1:n
counts = conv(counts,ones(1,d(k)));
end
% Possible values range from n to sum(d)
maxtot = sum(d);
vals = n:maxtot;
end
I noticed recently that my data is no longer updating on thingspeak again. Is there a connectivity issues with thingspeak
my code is as below:
#include "DHT.h"
#define DHTPIN 15 // what pin we're connected to
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
#define THINGSPEAK_API_KEY "1P4RY69D3YMP9R5W"
#include <SoftwareSerial.h>
#include <OneWire.h>
#include <DallasTemperature.h>
//-----------------------------
#include <ArduinoJson.h>
StaticJsonDocument<200>JsonDocument;
SoftwareSerialmyserial(10, 11);
//-------------------------
float voltage;
unsignedintfrac;
//---------------------
#define ONE_WIRE_BUS 5
OneWireoneWire(ONE_WIRE_BUS);
DallasTemperaturesensors(&oneWire);
floatCelcius = 0;
float Fahrenheit = 0;
//==========================================================================================================
bytesensorInterrupt = 0; // 0 = digital pin 2
bytesensorPin = 2;
// The hall-effect flow sensor outputs approximately 4.5 pulses per second per
// litre/minute of flow.
floatcalibrationFactor = 5.5; //==========================================================we change cal factor 4.5 to 5.5 if not work chnage again(4.5)
//========== 5.5 calibration factor is working efficent then 4.5 , 7.5 ,and 6.5
volatile byte pulseCount;
floatflowRate;
unsignedintflowMilliLitres;
unsigned long totalMilliLitres, tempTotal = -1;
unsigned long oldTime;
//-------------------------------------------------------
intpH_Value;
float Voltage;
//----------------------------------------------------------------------------------------------
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
myserial.begin(9600);
//--------------------------------
pinMode(sensorPin, INPUT);
digitalWrite(sensorPin, HIGH);
pulseCount = 0;
flowRate = 0.0;
flowMilliLitres = 0;
totalMilliLitres = 0; // ============================================================
oldTime = 0;
attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
sensors.begin();
//------------------------------------------------
/********************GSM Communication Starts********************/
if (myserial.available())
Serial.write(myserial.read());
myserial.println("AT");
delay(1000);
myserial.println("AT+SAPBR=3,1,\"Contype\",\"GPRS\"");
delay(1000);
ShowSerialData();
myserial.println("AT+SAPBR=3,1,\"APN\",\"www\"");//APN
delay(1000);
ShowSerialData();
myserial.println("AT+SAPBR=1,1");
delay(1000);
ShowSerialData();
myserial.println("AT+SAPBR=2,1");
delay(1000);
ShowSerialData();
//---------------------------------
}
void loop() {
// put your main code here, to run repeatedly:
inti;
for (i = 0; i< 20; i++)
{
flow_meter();
}
temperature();
turbidity();
delay(1000);
gsm();
}
voidflow_meter()
{
if ((millis() - oldTime) > 1000) // Only process counters once per second
{
// Disable the interrupt while calculating flow rate and sending the value to
// the host
detachInterrupt(sensorInterrupt);
// Because this loop may not complete in exactly 1 second intervals we calculate
// the number of milliseconds that have passed since the last execution and use
// that to scale the output. We also apply the calibrationFactor to scale the output
// based on the number of pulses per second per units of measure (litres/minute in
// this case) coming from the sensor.
flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / calibrationFactor;
// Note the time this processing pass was executed. Note that because we've
// disabled interrupts the millis() function won't actually be incrementing right
// at this point, but it will still return the value it was set to just before
// interrupts went away.
oldTime = millis();
// Divide the flow rate in litres/minute by 60 to determine how many litres have
// passed through the sensor in this 1 second interval, then multiply by 1000 to
// convert to millilitres.
flowMilliLitres = (flowRate / 60) * 1000;
// Add the millilitres passed in this second to the cumulative total
totalMilliLitres += flowMilliLitres;
// Print the flow rate for this second in litres / minute
/* Serial.print("Flow rate: ");
Serial.print(int(flowRate)); // Print the integer part of the variable
Serial.print("."); // Print the decimal point */
// Determine the fractional part. The 10 multiplier gives us 1 decimal place.
frac = (flowRate - int(flowRate)) * 10;
Serial.print(frac, DEC) ; // Print the fractional part of the variable
Serial.println("L/min");
/* // Print the number of litres flowed in this second
Serial.print(" Current Liquid Flowing: "); // Output separator
Serial.print(flowMilliLitres);
Serial.print("mL/Sec");
// Print the cumulative total of litres flowed since starting
Serial.print(" Output Liquid Quantity: "); // Output separator
Serial.print(totalMilliLitres);
Serial.println("mL"); */
if ( tempTotal != totalMilliLitres ) {
tempTotal = totalMilliLitres;
// displayVolumeOfWater(totalMilliLitres );
}
// Reset the pulse counter so we can start incrementing again
pulseCount = 0;
// Enable the interrupt again now that we've finished sending output
attachInterrupt(sensorInterrupt, pulseCounter, FALLING);
}
//=========================================================================================================================
}
voidpulseCounter()
{
// Increment the pulse counter
pulseCount++;
}
//-------------------------------------------------------------------------
void temperature()
{
sensors.requestTemperatures();
Celcius = sensors.getTempCByIndex(0);
Fahrenheit = sensors.toFahrenheit(Celcius);
Serial.print(" C ");
Serial.print(Celcius);
// Serial.print(" F ");
// Serial.println(Fahrenheit);
delay(1000);
}
//------------------------------------------------------------
void turbidity()
{
intsensorValue = analogRead(A0);
voltage = sensorValue * (5.0 / 1024.0);
// Serial.println ("Sensor Output (V):");
Serial.println (voltage);
// Serial.println();
delay(1000);
}
//------------------------------------------------------------
voidgsm()
{
myserial.println("AT+HTTPINIT");
delay(1000);
ShowSerialData();
myserial.println("AT+HTTPPARA=\"CID\",1");
delay(1000);
ShowSerialData();
StaticJsonDocument<200>JsonDocument;
JsonObject& object = JsonDocument.createObject();
object.set("TE", Celcius);
object.set("TU", voltage);
object.set("WF", frac);
delay(1000);
object.printTo(Serial);
Serial.println(" ");
String sendtoserver;
object.prettyPrintTo(sendtoserver);
delay(1000);
//myserial.println("AT+HTTPPARA=\"URL\",\"https://api.thingspeak.com/update?api_key=\""); //Server address
myserial.println("AT+HTTPPARA=\"URL\",\"https://api.thingspeak.com/update?api_key=\""); //Server address
delay(1000);
ShowSerialData();
myserial.println("AT+HTTPPARA=\"CONTENT\",\"application/json\"");
delay(1000);
ShowSerialData();
myserial.println("AT+HTTPDATA=" + String(sendtoserver.length()) + ",100000");
Serial.println(sendtoserver);
delay(1000);
ShowSerialData();
myserial.println(sendtoserver);
delay(2000);
ShowSerialData;
myserial.println("AT+HTTPACTION=1");
delay(1000);
ShowSerialData();
myserial.println("AT+HTTPREAD");
delay(1000);
ShowSerialData();
myserial.println("AT+HTTPTERM");
delay(1000);
ShowSerialData;
}
voidShowSerialData()
{
while (myserial.available() != 0)
Serial.write(myserial.read());
delay(1000);
}
My following code works running Matlab 2024b for all test cases. However, 3 of 7 tests fail (#1, #4, & #5) the QWERTY Shift Encoder problem. Any ideas what I am missing?
Thanks in advance.
keyboardMap1 = {'qwertyuiop[;'; 'asdfghjkl;'; 'zxcvbnm,'};
keyboardMap2 = {'QWERTYUIOP{'; 'ASDFGHJKL:'; 'ZXCVBNM<'};
if length(s) == 0
se = s;
end
for i = 1:length(s)
if double(s(i)) >= 65 && s(i) <= 90
row = 1;
col = 1;
while ~strcmp(s(i), keyboardMap2{row}(col))
if col < length(keyboardMap2{row})
col = col + 1;
else
row = row + 1;
col = 1;
end
end
se(i) = keyboardMap2{row}(col + 1);
elseif double(s(i)) >= 97 && s(i) <= 122
row = 1;
col = 1;
while ~strcmp(s(i), keyboardMap1{row}(col))
if col < length(keyboardMap1{row})
col = col + 1;
else
row = row + 1;
col = 1;
end
end
se(i) = keyboardMap1{row}(col + 1);
else
se(i) = s(i);
end
% if ~(s(i) = 65 && s(i) <= 90) && ~(s(i) >= 97 && s(i) <= 122)
% se(i) = s(i);
% end
end
Need code to collect data of waterflow sensor using ESP 8266 and to stoe it in ThingSpeak cloud
Ciao a Tutti,qualche mese fa avevo costruito una stazione meteo con un esp32 e vari sensori.
Tutto funzionava, adesso però ho riprovato, e non funziona più. Ho provato a creare un canale nuovo con nuovo ID canale, nuovo ID Client, nuovo Utente (uguale al Client) e nuova Password. si connette (ho inserito un comando se connesso a MQTT scrivi.....) ma non publica i dati.
Non reisco a saltarne fuori, ècambiato qualche cosa?
grazie a tutti
Hello,
could it be that there is currently is a stability problem with the MQTT-Broker? I can establisth a connection successfully using the MQTTX client (web and win64 installation). I tried all possible ports an connection types. It disconnects all the time after a few seconds of establishing a connection successfully. So it was not possible to subscribe any item. I do not think the problem is in my side... By the way, protocol verision 3.1.1 ist supported, 5.0 not, am I right?
Maybe you could give me a hint,
Best regards,
Manfred
私の場合、前の会社が音楽認識アプリの会社で、アルゴリズム開発でFFTが使われていたことがきっかけでした。でも、MATLABのすごさが分かったのは、機械学習のオンライン講座で、Andrew Ngが、線型代数を使うと、数式と非常に近い構文のコードで問題が処理できることを学んだ時でした。
in the below code write is working fine, but read is failing ( 404 error) can you please help me reslove this.
/*
Go to thingspeak.com and create an account if you don't have one already.
After logging in, click on the "New Channel" button to create a new channel for your data. This is where your data will be stored and displayed.
Fill in the Name, Description, and other fields for your channel as desired, then click the "Save Channel" button.
Take note of the "Write API Key" located in the "API keys" tab, this is the key you will use to send data to your channel.
Replace the channelID from tab "Channel Settings" and privateKey with "Read API Keys" from "API Keys" tab.
Replace the host variable with the thingspeak server hostname "api.thingspeak.com"
Upload the sketch to your ESP32 board and make sure that the board is connected to the internet. The ESP32 should now send data to your Thingspeak channel at the intervals specified by the loop function.
Go to the channel view page on thingspeak and check the "Field1" for the new incoming data.
You can use the data visualization and analysis tools provided by Thingspeak to display and process your data in various ways.
Please note, that Thingspeak accepts only integer values.
You can later check the values at https://thingspeak.com/channels/2005329
Please note that this public channel can be accessed by anyone and it is possible that more people will write their values.
*/
#include <WiFi.h>
const char *ssid = "xxxx"; // Change this to your WiFi SSID
const char *password = "xxxxx"; // Change this to your WiFi password
const char *host = "api.thingspeak.com"; // This should not be changed
const int httpPort = 80; // This should not be changed
const String channelID = "2805914"; // Change this to your channel ID
const String writeApiKey = "xxxxxxxxxxxxxxxx"; // Change this to your Write API key
const String readApiKey = "xxxxxxxxxxxxxxxx"; // Change this to your Read API key
// The default example accepts one data filed named "field1"
// For your own server you can ofcourse create more of them.
int field1 = 20;
//int field1 = 20;
int numberOfResults = 1; // Number of results to be read
int fieldNumber = 1; // Field number which will be read out
void setup() {
Serial.begin(115200);
while (!Serial) {
delay(100);
}
// We start by connecting to a WiFi network
Serial.println();
Serial.println("******************************************************");
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
void readResponse(NetworkClient *client) {
unsigned long timeout = millis();
while (client->available() == 0) {
if (millis() - timeout > 5000) {
Serial.println(">>> Client Timeout !");
client->stop();
return;
}
}
// Read all the lines of the reply from server and print them to Serial
while (client->available()) {
String line = client->readStringUntil('\r');
Serial.print(line);
}
Serial.printf("\nClosing connection\n\n");
}
void loop() {
NetworkClient client;
String footer = String(" HTTP/1.1\r\n") + "Host: " + String(host) + "\r\n" + "Connection: close\r\n\r\n";
// WRITE --------------------------------------------------------------------------------------------
if (!client.connect(host, httpPort)) {
return;
}
client.print("GET /update?api_key=" + writeApiKey + "&field1=" + field1 + footer);
readResponse(&client);
delay(200);
// READ --------------------------------------------------------------------------------------------
String readRequest = "GET /channels/" + channelID + "/fields/" + fieldNumber + ".json?results=" + numberOfResults + " HTTP/1.1\r\n" + "Host: " + host + "\r\n"
+ "Connection: close\r\n\r\n";
if (!client.connect(host, httpPort)) {
return;
}
client.print(readRequest);
readResponse(&client);
// -------------------------------------------------------------------------------------------------
//++field1;
delay(10000);
}
Thingspeak
Thingspeak channel shows a "watch" - "un-watch" selection box. What does this do?
Thanks
Attaching the Photoshop file if you want to modify the caption.
Toolbox 全部入りの MATLAB ライセンス
67%
まだ持っていない Toolbox (下記にコメントください）
0%
MATLAB T シャツ
17%
MATLAB ルービックキューブ
0%
MATLAB 靴下
6%
MathWorks オフィス訪問チケット
11%
18 votes
この場は MATLAB や Simulink を使っている皆さんが、気軽に質問や情報交換ができる場所として作られました。日本語でも気軽に投稿ができるように今回日本語チャネルを解説します。
ユーザーの皆様とのやり取りを通じて、みんなで知識や経験を共有し、一緒にスキルアップしていきましょう。 どうぞお気軽にご参加ください。
そして日本語チャネル開設にあたってコメントくださった皆様、ありがとうございます！
Dear Sir,
I login my channel in a device using my user name and password (also client id & password) but when I also login using the same user name and password in another device, the first one connection was forced disconnected. I want to publish via thinkspeak mqtt by using the two devices. Please advise how I can do it. Can I use the same thinkspeak user name to login? Is it needed to have another thinkspeak user to login? In this case, please also advise. Many thanks.
Aaron
