I need to find a way to create a new array in Java that will insert intermediate values between the values of an already-existing array.

grow intermediate values in array.java

  /**
   * >   arr = {1, 2, 3}, size = 5
   * <   [1.0, 1.5, 2.0, 2.5, 3.0]
   * @param arr
   * @param newSize
   * @return
   */
  public static double[] growIntermediate(double[] arr, int newSize) {
    if (newSize < arr.length) {
      throw new IllegalArgumentException("newSize lower than array length");
    }
    if (newSize == arr.length) {
      return arr;
    }
    int skip = max(1, arr.length / (newSize - arr.length));
    int minFills = max(1, (newSize - arr.length) / arr.length);
    log.debug("skip:{}, minFills:{}", skip, minFills);
    int idx = 0;
    int destPos = 0;
    double[] ret = new double[newSize];
    while (idx < arr.length) {
      System.arraycopy(arr, idx, ret, destPos, min(skip, arr.length - idx));
      idx += skip;
      destPos += skip;
      if ((destPos + minFills < newSize) && (idx < arr.length)) {
        final double[] intheBetween = intheBetween(arr[idx - 1], arr[idx], minFills);
        System.arraycopy(intheBetween, 0, ret, destPos, minFills);
        destPos += minFills;
      }
    }
    double[] rett = new double[destPos];
    System.arraycopy(ret, 0, rett, 0, destPos);
    return rett;
  }

  /**
   * > intheBetween(0, 1, 3)
   * < [0.3333333333333333, 0.6666666666666666]
   */
  public static double[] intheBetween(double a, double b, int n) {
    double step = (b - a) / (n + 1);
    return range(0, n).mapToDouble(i -> a + (step * (i + 1))).toArray();
  }