docs: public static int argMin(final double[] x) {
      checkArgument(x.length > 0);
      double minValue = Double.MAX_VALUE;
      int minIndex = 0;
  
      for (int i = 0; i < x.length; ++i) {
        final double val = x[i];
        if (val < minValue) {
          minIndex = i;
          minValue = val;
        }
      }
      return minIndex;
    }