Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I've used a <a href="http://download.oracle.com/javase/1.4.2/docs/api/java/util/HashMap.html" rel="nofollow">HashMap</a> to replace the js {} dynamic object instance and floats, but @weberik's port looks more straightforward.</p> <pre><code>void setup() { int numValues = 10; float[] values = new float[numValues]; //Create an empty sample array for(int i = 0 ; i &lt; numValues ; i++) values[i] = random(0.0,100.0); //Populate it with random values. println("mode: " + mode(values)); } float mode(float[] source) { if (source.length == 0) return -1; HashMap&lt;Float,Integer&gt; modeMap = new HashMap&lt;Float,Integer&gt;(); float result = source[0]; int maxCount = 1; for (int i = 0; i &lt; source.length; i++) { float el = source[i]; if (modeMap.get(el) == null) modeMap.put(el,1); else modeMap.put(el,modeMap.get(el)+1); if (modeMap.get(el) &gt; maxCount) { result = el; maxCount = modeMap.get(el); } } return result; } </code></pre> <p>You've mentioned sensor input, so I presume data will be sampled continuously, so values could be stored at a certain interval, then sent to Processing for the mode. Just a wild guess, but isn't she looking to average/smooth out sensor readings a bit? If so, she could cache a few values (say 10) in an array in Arduino and get the average everytime a new values is added:</p> <pre><code>int vals[10]; //Array to store caches values. void setup() { Serial.begin(9600); for (int i=0 ; i &lt; 10 ; i++) vals[i] = 0; //Init with zeroes } void loop() { delay(100); int currentVal = average(analogRead(0)); //Serial.print(currentVal,BYTE); Serial.println(currentVal); } int average(int newVal) { int total = 0; //Used to store the addition of all currently cached values for(int i = 9; i &gt; 0; i--) { //Loop backwards from the one before last to 0 vals[i] = vals[i-1]; //Overwrite the prev. value with the current(shift values in array by 1) total += vals[i]; //Add to total } vals[0] = newVal; //Add the newest value at the start of the array total += vals[0]; //Add that to the total as well return total *= .1; //Get the average (for 10 elemnts) same as total /= 10, but multiplication is faster than division. } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow to calculate the statistical mode in Processing / Arduino
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USPeter Mortensen
    1. USGeorge Profenza
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThe thought of using a template on a micrcontroller makes my mind bleed. The inefficiencies are painful. On that note, you did show how to port the code over, if it will compile on arduino, I am not sure.
      singulars
      1. PO
      1. USKortuk
    2. COThanks George, very thoughtful response. Indeed she would have to average the readings a bit, and your solution is clear and made me learn about HashMaps! Do you think it might be done in Arduino alone (excluding the Processing part)? Don't show me code, but the answer :)
      singulars
      1. PO
      1. USSergio Majluf
    3. COKortuk, you are right about efficiency, but that's not the target for Arduino...it's supposed to make it simple/less scary for anyone with little or no programming experience to use a microcontroller. Regarding the ported code, that is for Processing/Java, not Arduino, so it will no run on Arduino obviosuly, but values can be sent from Arduino to Processing via the built-in Serial library.
      singulars
      1. PO
      1. USGeorge Profenza
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload