@Override
  public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations)
      throws Exception {
    configurations.setAccessStrategy(new RowByRowAccessStrategy()).setOutputDataType(Type.DOUBLE);
    s = parameters.getStringOrDefault("coef", "");
    method = parameters.getStringOrDefault("method", "");
    layer = parameters.getIntOrDefault("layer", 1);
    timestamp.clear();
    value.clear();
  }
This function calculates inverse discrete wavelet transform of an input series, which is composed
of multiple layers. Input series must be an integer exponent of 2. Input series is treated as
sampled in equal distances.
library-udf/src/main/java/org/apache/iotdb/library/frequency/UDTFIDWT.java