Discrete Cosine Transform将一个在时间域(time domain)内长度为N的实值序列转换为另外一个在频率域(frequency domain)内的长度为N的实值序列。下面是程序调用的例子。
time domain
N
frequency domain
import org.apache.spark.ml.feature.DCTimport org.apache.spark.ml.linalg.Vectorsval data = Seq( Vectors.dense(0.0, 1.0, -2.0, 3.0), Vectors.dense(-1.0, 2.0, 4.0, -7.0), Vectors.dense(14.0, -2.0, -5.0, 1.0))val df = spark.createDataFrame(data.map(Tuple1.apply)).toDF("features")val dct = new DCT() .setInputCol("features") .setOutputCol("featuresDCT") .setInverse(false)val dctDf = dct.transform(df)dctDf.select("featuresDCT").show(3)
import org.apache.spark.ml.feature.DCT
import org.apache.spark.ml.linalg.Vectors
val data = Seq(
Vectors.dense(0.0, 1.0, -2.0, 3.0),
Vectors.dense(-1.0, 2.0, 4.0, -7.0),
Vectors.dense(14.0, -2.0, -5.0, 1.0))
val df = spark.createDataFrame(data.map(Tuple1.apply)).toDF("features")
val dct = new DCT()
.setInputCol("features")
.setOutputCol("featuresDCT")
.setInverse(false)
val dctDf = dct.transform(df)
dctDf.select("featuresDCT").show(3)
