static float[] toFloatArray(L<Float> l) {
  float[] a = new float[l(l)];
  for (int i = 0; i < a.length; i++)
    a[i] = l.get(i);
  ret a;
}

static float[] toFloatArray(double[] l) {
  float[] a = new[l(l)];
  for (int i = 0; i < a.length; i++)
    a[i] = (float) l[i];
  ret a;
}

Began life as a copy of #1004992