krishnanraman

scala> import java.util.concurrent.TimeUnit
import java.util.concurrent.TimeUnit

scala> val units = List((TimeUnit.DAYS,"days"),(TimeUnit.HOURS,"hours"), (TimeUnit.MINUTES,"minutes"), (TimeUnit.SECONDS,"seconds"))
units: List[(java.util.concurrent.TimeUnit, String)] = List((DAYS,days), (HOURS,hours), (MINUTES,minutes), (SECONDS,seconds))

scala> def humanReadable(timediff:Long):String = {
     | val init = ("", timediff)
     | units.foldLeft(init){ case (acc,next) =>
     | val (human, rest) = acc

krishnanraman

Vickrey Auction

System Description: There are n bidders
each bidder has a bid b(i) and a true value v(i) that the item is truly worth

payoff to bidder = v(i) - b(i)
payoff too bidder = 0, if I lose.

The winner of the auction has the highest bid.
However, the winner doesn't pay the highest bid, he pays the second highest bid.

krishnanraman

P1

why ?
Too many images, how to search ?
a. human annotation impractical
b. Content Based Image Retrieval - cbir identifies low-level features (color/shape/texture), 
   need higher level because SEMANTIC GAP
   SEMANTIC GAP= (gap b/w lower-level features & semantic concepts used by humans to describe images)
c. Automatic Image Annotation

krishnanraman

object ClusterTree {


    /*
    Draw a decision tree in html5 using the canvas api
    Returns a valid html5 string, that can be persisted to some foo.html
    */

    /*
    define vertex V & edge E

krishnanraman

package com.marin.dt
import org.apache.spark.rdd.RDD
import org.apache.spark.mllib.tree.DecisionTree
import org.apache.spark.mllib.tree.model.{DecisionTreeModel,Node}
import org.apache.spark.mllib.tree.configuration.Algo
import org.apache.spark.mllib.evaluation.RegressionMetrics

/*
Collection of routines to Prune a Decision Tree, & enable the following features
1. Traverse a decision tree

krishnanraman

On the line segment joining 1 to i,
the contour integral of 1/z^k for various powers of k works out to:

Integral(1/z^1) <= 2
Integral(1/z^2) <= 2*sqrt(2)
Integral(1/z^3) <= 4
Integral(1/z^4) <= 4*sqrt(2)
Integral(1/z^5) <= 8
Integral(1/z^6) <= 8*sqrt(2)
...

krishnanraman

    Given a date like 2015-12-31, obtain 2015-12-30
    */
    def getPreviousDay(mydate:String):String = {
        val fmt = new SimpleDateFormat("yyyy-MM-dd")
        val date = fmt.parse(mydate)
        val cal = Calendar.getInstance
        cal.setTime(date)
        cal.add(Calendar.DAY_OF_MONTH,-1)
        fmt.format(cal.getTime)
    }

krishnanraman

import scala.reflect.ClassTag
import org.apache.spark.rdd.RDD

object Splitter {
  def split[T:ClassTag, U:ClassTag](rdd:RDD[T], f:T=>U) = {
    val splits = rdd.groupBy{ x:T => f(x) } 
    val keys:Seq[U] = splits.keys.collect().toSeq
    keys.foreach{ key:U =>
      splits
      .filter{ x => x._1 == key } // get records that match this key

krishnanraman

$ ls -l
0
1
2
3
4
5
6
7
8

krishnanraman

Desired Sum: 1 Possible ? false Subset:List()
Desired Sum: 2 Possible ? true Subset:List(List(2))
Desired Sum: 3 Possible ? true Subset:List(List(2, 3))
Desired Sum: 4 Possible ? false Subset:List()
Desired Sum: 5 Possible ? true Subset:List(List(2, 3, 5), List(2, 5))
Desired Sum: 6 Possible ? false Subset:List()
Desired Sum: 7 Possible ? true Subset:List(List(2, 3, 5, 7), List(2, 5, 7), List(2, 7))
Desired Sum: 8 Possible ? true Subset:List(List(2, 3, 5, 7, 8))
Desired Sum: 9 Possible ? true Subset:List(List(2, 3, 5, 7, 8), List(2, 5, 7), List(2, 7))
Desired Sum: 10 Possible ? true Subset:List(List(2, 3, 5, 7, 8))