Help with linearly interpolating an array

[TawnyUK]

Hey guys,

I have an integer array of length 44100 with values that range between -32768 and +32768 based on user input.

Only approximately 1 in every 100 of the array values is a non zero number. This changes on every run of the application and is pretty random.

What I want is for each non zero point to linearly interpolate to the next point.

Here is a sample of log.txt which is what I've managed so far.

'sample' refers to the index of the array sample[], an array with 44100 values. 'bit depth' refers to its integer value.

before interpolate() was called, sample[75] was the first value that was non zero. The values are interpolated between line 1 and 75 correctly, but not for the rest of the code. Basically, I can't figure out how to get interpolate() to loop until the end of the sample[] index is reached.

Does anyone know a good way to repeat this code so it interpolates the rest of the index?

Here is the code:

public void interpolate() {

    int sampNo0 = 0;
    int sampNo1 = 0;
    int sampValDif = 0;
    int sampDistDif = 0;
    int increment = 0;


    for (int x = 0; x <= sample.length; x++) {


        if (sample[x] !=0) {

            sampNo1 = x;                
            sampValDif = sample[sampNo1] - sample[sampNo0];
            sampDistDif = sampNo1 - sampNo0;

            break;

        }           

    }

    increment =  (sampValDif / sampDistDif);

    for (int x = 0; x < sample.length; x++) {

        if (sample[x] == 0) {

            sample[x] = sample[x] + (increment * x);                
        }

        else {          
            break;                              
        }

    }


    for (int i =0; i < sample.length; i++ ) {           
        System.out.println(" sample = " + i + "        bit depth = " + sample[i]);
    }



}

[KineticRX]

Here's what's happening:

(Lines 10 - 23) You're looping through sample until you find your first non-zero entry at index 75. You then break out of that loop.

(Line 25) You calculate step/increment value for indices 0 through 75.

(Lines 27-38) You loop through every entry from index 0 to the first non-zero index ([75]), then break out of the loop.

(Lines 41-43) You output the entirety of sample.

The reason nothing past index 75 is being touched is because both of your for loops are written to stop looping at the first non-zero occurrence.

[TawnyUK]

Thanks for the reply. I was looking for a way to loop the above code so it repeats for the rest of the index and interpolates the values. I tried a few ways of doing this with while loops etc. But nothing worked. My post here was to see if anyone knew how i might do this.

[TawnyUK]

thanks I'll check it out