Question

我正在尝试使用Breeze Linear Algebra软件包（https://github.com/scalanlp/breeze）和我自己的代表GF2字段的数据类型来实现Humming编码。到目前为止，我成功地实现了我的GF2：

package humming

trait GF2 {
  def + (that: GF2): GF2
  def * (that: GF2): GF2

  def / (that: GF2) = that match {
    case Zero => throw new IllegalArgumentException("Div by 0")
    case _ => this
  }
}

object Zero extends GF2 {
  override def toString = "Zero"
  def + (that: GF2) = that
  def * (that: GF2) = this
}

object One extends GF2 {
  override def toString = "One"
  def + (that: GF2) = that match { case One => Zero ; case _ => this }
  def * (that: GF2) = that match { case One => this ; case _ => that }
}

和需要的类型类来创建GF2值矩阵：

import breeze.linalg._
import breeze.numerics._
import breeze.storage._
import scala.reflect._
import breeze.math._
import humming._

implicit object GF2DefaultArrayValue extends DefaultArrayValue[GF2] {
  override def value = Zero
}

implicit object GF2Semiring extends Semiring[GF2] {
  def defaultArrayValue = GF2DefaultArrayValue
  def manifest = classTag[GF2]
  def zero = Zero
  def one = One

  def ==(a: GF2, b: GF2) = a == b
  def !=(a: GF2, b: GF2) = a != b
  def +(a: GF2, b: GF2) = a + b
  def *(a: GF2, b: GF2) = a * b
}

val a = DenseMatrix.eye[GF2](5)

但是当我尝试向自身添加矩阵时，我收到以下错误：

a + a  
// could not find implicit value for parameter op:  
// breeze.linalg.operators.BinaryOp[breeze.linalg.DenseMatrix[humming.GF2],  
// breeze.linalg.DenseMatrix[humming.GF2],breeze.linalg.operators.OpAdd,That]

此时我被卡住了，因为我不太明白我现在应该实现什么类型的类。看breeze.linalg.operators并没什么帮助。所以问题是我应该怎么做才能将我的GF2与Breeze结合起来，以便支持所有矩阵/向量操作？

==============
上述问题在0.6版本中解决了
但是，我仍然无法通过向量或值乘以矩阵：

val a = DenseMatrix.eye[GF2](5)
val b = DenseVector.ones[GF2](5)
a + a // OK

a * b  
// Could not find an implicit implementation for this UFunc with arguments  
// breeze.linalg.DenseMatrix[humming.GF2], breeze.linalg.DenseVector[humming.GF2]

a + One  
// Could not find an implicit implementation for this UFunc with arguments  
// breeze.linalg.DenseMatrix[humming.GF2], humming.One.type

我想我必须提供UFunc实施。它应该是什么样的？

Answer 1

这适用于Breeze的最新快照。我本周末将发布0.6。

scala> val a = DenseMatrix.eye[GF2](5)
a: breeze.linalg.DenseMatrix[X.GF2] =
One   Zero  Zero  Zero  Zero
Zero  One   Zero  Zero  Zero
Zero  Zero  One   Zero  Zero
Zero  Zero  Zero  One   Zero
Zero  Zero  Zero  Zero  One

scala> a + a
res0: breeze.linalg.DenseMatrix[X.GF2] =
Zero  Zero  Zero  Zero  Zero
Zero  Zero  Zero  Zero  Zero
Zero  Zero  Zero  Zero  Zero
Zero  Zero  Zero  Zero  Zero
Zero  Zero  Zero  Zero  Zero

具有自定义数据类型的Breeze Linear Algebra

1 个答案: