Using R from Scala

r in scala.txt

Step 0. You must have the latest & greatest version of R, and scala 2.10.1, for all of this to work.

Step 1. Download and unzip the MacOS X Binary jvmr_1.0.4.tgz from here: http://cran.r-project.org/web/packages/jvmr/index.html

Step 2. Create a lib folder, and copy jvmr_2.10-1.0.4.jar to that folder.

Step 3. Start R

Step 4. At the R console
>install.packages("jvmr")
>library(jvmr)

Step 5. Start sbt version 2.10.1 in console mode like so -

$ sbt "++ 2.10.1" console
[info] Set current project to default-0844fb (in build file:/Users/kraman/workspace/jvmr/)
Setting version to 2.10.1
[info] Set current project to default-0844fb (in build file:/Users/kraman/workspace/jvmr/)
[info] Starting scala interpreter...
[info] 
Welcome to Scala version 2.10.1 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_65).
Type in expressions to have them evaluated.
Type :help for more information.

scala> 
scala> import org.ddahl.jvmr.RInScala
import org.ddahl.jvmr.RInScala

scala> val R = RInScala()
R: org.ddahl.jvmr.RInScala = org.ddahl.jvmr.RInScala@511192bd

// zscores : See http://upload.wikimedia.org/wikipedia/commons/b/bb/Normal_distribution_and_scales.gif
// zscore = number of standard deviations above the mean
// at 3 sigma, area under curve is 99% of distribution
// at -3 sigma, insignificant area, almost 0%
// at 0, exactly 50% area

scala> val zscores = -3.0 to 3.0 by 0.1

scala> def pvalue(zScore:Double) = R.toPrimitive[Double]("pnorm(%s,0,1)".format(zScore))
pvalue: (zScore: Double)Double

scala> zscores foreach { z=> printf("%.3f\t%.3f\n", z, pvalue(z)) }

-3.000	0.001
-2.900	0.002
-2.800	0.003
-2.700	0.003
-2.600	0.005
-2.500	0.006
-2.400	0.008
-2.300	0.011
-2.200	0.014
-2.100	0.018
-2.000	0.023
-1.900	0.029
-1.800	0.036
-1.700	0.045
-1.600	0.055
-1.500	0.067
-1.400	0.081
-1.300	0.097
-1.200	0.115
-1.100	0.136
-1.000	0.159
-0.900	0.184
-0.800	0.212
-0.700	0.242
-0.600	0.274
-0.500	0.309
-0.400	0.345
-0.300	0.382
-0.200	0.421
-0.100	0.460
0.000	0.500
0.100	0.540
0.200	0.579
0.300	0.618
0.400	0.655
0.500	0.691
0.600	0.726
0.700	0.758
0.800	0.788
0.900	0.816
1.000	0.841
1.100	0.864
1.200	0.885
1.300	0.903
1.400	0.919
1.500	0.933
1.600	0.945
1.700	0.955
1.800	0.964
1.900	0.971
2.000	0.977
2.100	0.982
2.200	0.986
2.300	0.989
2.400	0.992
2.500	0.994
2.600	0.995
2.700	0.997
2.800	0.997
2.900	0.998
3.000	0.999


def plot(x:List[Int], y:List[Double]) = R.apply("plot("+"c"+x.toString.substring(4)+",c"+y.toString.substring(4)+",xlab=\"\", ylab=\"\", type=\"b\", col=\"red\",main=\"graph\")")
val x = (1 to 100).toList
val y = x.map( i=> math.random * 100 + i )
plot(x,y)

( THANKS TO Chang Su / CSL FOR MAJOR HELP WITH SBT )