scala sparseVetor， SprseMatrix 实现

def rand(seed:Int):Double={  val rand=new Random(seed)  rand.nextDouble()}

def rand2(size:Int,seed:Int):SparseVector={  val rand=new Random(seed)  val ret_indices=Array.range(0,size)  val ret_values=Array.tabulate[Double](size)(i=>rand.nextDouble())  //从函数创建数组  Vectors.sparse(size, ret_indices, ret_values).asInstanceOf[SparseVector]}

调用：val w=rand2(4,3)  返回，SparseVector有3个要素函数，size,indices,values. 取某一部分就调用那3个函数。比如：w.size=4,w.indices=(1,2,3,4)

def rand3(numRows:Int,numCols:Int,seed:Int):SparseMatrix={  val rand=new Random(seed)  val ret_rowIndices=new ArrayBuffer[Int]()  for (i <-0 to numCols-1) {    ret_rowIndices ++= Array.range(0,numRows)  }  val ret_colPtrs=Array.range(0,numCols+1).map(x=>x * numRows)  val ret_values=Array.tabulate[Double](numRows*numCols)(i=>rand.nextDouble())  Matrices.sparse(numRows, numCols, ret_colPtrs.toArray,ret_rowIndices.toArray, ret_values.toArray).asInstanceOf[SparseMatrix]}