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https://issues.apache.org/jira/browse/MAHOUT-1856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15833732#comment-15833732
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ASF GitHub Bot commented on MAHOUT-1856:
----------------------------------------
Github user andrewpalumbo commented on a diff in the pull request:
https://github.com/apache/mahout/pull/246#discussion_r97235959
--- Diff:
math-scala/src/main/scala/org/apache/mahout/math/algorithms/transformer/MeanCenter.scala
---
@@ -0,0 +1,93 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.mahout.math.algorithms.transformer
+
+import collection._
+import JavaConversions._
+import org.apache.mahout.math.drm._
+import org.apache.mahout.math.drm.RLikeDrmOps._
+import org.apache.mahout.math.{Matrix, Vector}
+import org.apache.mahout.math.scalabindings.RLikeOps._
+import org.apache.mahout.math.scalabindings.MahoutCollections._
+import org.apache.mahout.math.{Vector => MahoutVector}
+
+import scala.reflect.ClassTag
+
+class MeanCenter extends Transformer {
+
+ var summary = ""
+ var colMeansV: MahoutVector = _
+
+ /**
+ * Optionally set the centers of each column to some value other than
Zero
+ * @param centers A vector of length equal to the `input` in the fit
method specifying the
+ * centers to set each column to.
+ */
+ def setCenter(centers: MahoutVector) = {
+ colMeansV = colMeansV - centers
+ }
+
+ /**
+ * Centers Columns at zero
+ * @param input
+ */
+ def fit[K](input: DrmLike[K]) = {
+ colMeansV = input.colMeans
+ val colMeansA = colMeansV.toArray
+ //summary = (0 until colMeansA.length).map(i => s"Column ${i} mean:
${colMeansA(i)}").mkString(", ")
+ }
+
+ def transform[K: ClassTag](input: DrmLike[K]): DrmLike[K] = {
+
+ if (!isFit) {
+ //throw an error
+ }
+
+ implicit val ctx = input.context
+ val bcastV = drmBroadcast(colMeansV)
+
+ val output = input.mapBlock(input.ncol) {
+ case (keys, block) =>
+ val copy: Matrix = block.cloned
+ copy.foreach(row => row -= bcastV.value)
+ (keys, copy)
+ }
+ output
+ }
+
+ def invTransform[K: ClassTag](input: DrmLike[K]): DrmLike[K] = {
+
+ if (!isFit) {
+ //throw an error
--- End diff --
Same qestion here as before- do you want to throw an error here?
> Create a framework for new Mahout Clustering, Classification, and
> Optimization Algorithms
> ------------------------------------------------------------------------------------------
>
> Key: MAHOUT-1856
> URL: https://issues.apache.org/jira/browse/MAHOUT-1856
> Project: Mahout
> Issue Type: New Feature
> Affects Versions: 0.12.1
> Reporter: Andrew Palumbo
> Assignee: Trevor Grant
> Priority: Critical
> Fix For: 0.13.0
>
>
> To ensure that Mahout does not become "A loose bag of algorithms", Create
> basic traits with funtions common to each class of algorithm.
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