Calling toString on a DenseMatrix with zero rows and some columns throws java.lang.UnsupportedOperationException: empty.max

[rossetd0]

Try the following in the REPL:

This works:

scala> breeze.linalg.DenseMatrix.zeros[Int](0,2).toString
scala> breeze.linalg.DenseVector[Int]().toString

This throws java.lang.UnsupportedOperationException: empty.max :

scala> breeze.linalg.DenseMatrix.zeros[Int](0,2).toString
java.lang.UnsupportedOperationException: empty.max
    at scala.collection.TraversableOnce$class.max(TraversableOnce.scala:201)
    at scala.collection.immutable.Vector.max(Vector.scala:63)
    at breeze.linalg.Matrix$class.colWidth$1(Matrix.scala:68)
    at breeze.linalg.Matrix$class.toString(Matrix.scala:73)

The culprit is the following line:

    def colWidth(col : Int) =
      (0 until showRows).map(row => this(row,col).toString.length+2).max

which should be replaced by:

    def colWidth(col : Int) =
      if (showRows > 0) (0 until showRows).map(row => this(row,col).toString.length+2).max else 0

or something approaching.

Thanks for any correction!

Denis

[dlwh]

thanks!