Hiroshi Takahashi created SPARK-10127:
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Summary: Add numpy-like indexing interface for DenceMatrix
Key: SPARK-10127
URL: https://issues.apache.org/jira/browse/SPARK-10127
Project: Spark
Issue Type: New Feature
Components: MLlib
Reporter: Hiroshi Takahashi
Currently, we don't have good interface to access sub-matrix.
It's inconvenience to prototype manipulate matrix via spark-shell for the
reason.
My suggestion is to add operator "!" as operator of accessing sub-matrix
instead of numpy's ().
for example:
{code}
scala> import org.apache.spark.mllib.linalg.DenseMatrix
import org.apache.spark.mllib.linalg.DenseMatrix
scala> val dm = new DenseMatrix(3, 3, Array(1.0, 4.0, 7.0, 2.0, 5.0, 8.0, 3.0,
6.0, 9.0))
dm: org.apache.spark.mllib.linalg.DenseMatrix =
1.0 2.0 3.0
4.0 5.0 6.0
7.0 8.0 9.0
// get row
scala> dm!(1)
res0: org.apache.spark.mllib.linalg.DenseMatrix = 4.0 5.0 6.0
// get (i, j)
scala> dm!(1, 2)
res1: Double = 6.0
// get colmun
scala> dm!((), 1)
res2: org.apache.spark.mllib.linalg.DenseMatrix =
2.0
5.0
8.0
// get columns between i and j-1
scala> dm!((), (1, 3))
res3: org.apache.spark.mllib.linalg.DenseMatrix =
2.0 3.0
5.0 6.0
8.0 9.0
// get rows between i and j-1
scala> dm!((1, 3))
res4: org.apache.spark.mllib.linalg.DenseMatrix =
4.0 5.0 6.0
7.0 8.0 9.0
// get sub-matrix between (i1, j1-1) and (i2, j2-1)
scala> dm!((1, 3), (1, 3))
res5: org.apache.spark.mllib.linalg.DenseMatrix =
5.0 6.0
8.0 9.0
{code}
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