Interpolation over an array (or two)

Question

I\'m looking for a java library or some help to write my own interpolation function. That is I have two arrays of doubles which are potentially different sizes, but are ord

Answer 1

Light-weight version of one-dimensional array linear interpolator:

public static float[] interpolate(float[] data) {
    int startIdx = -1;
    float startValue = 0f;
    float element;
    for (int i = 0; i < data.length - 1; i++) {
        element = data[i];
        if (element != 0f) {
            if (startIdx != -1) {
                doInterpolate(startValue, element, startIdx + 1, i - startIdx - 1, data);
            }
            startValue = element;
            startIdx = i;
        }
    }
    return data;
}

private static void doInterpolate(float start, float end, int startIdx, int count, float[] data) {
    float delta = (end - start) / (count + 1);
    for (int i = startIdx; i < startIdx + count; i++) {
        data[i] = start + delta * (i - startIdx + 1);
    }
}