How to get R.Net work with VB.Net

Question

I am trying to get R.Net work with VB.NET. I translated an official example from c# to vb.net but it is not working. There are different things I tried. First I used the SetupHelper as explained on the official page.

Imports System.IO

Namespace RDotNetSetup

Public Class SetupHelper
Public Shared Sub SetupPath()
    Dim oldPath = System.Environment.GetEnvironmentVariable("PATH")
    Dim rPath = If(System.Environment.Is64BitProcess, "C:\Program Files\R\R-3.0.2\bin\x64", "C:\Program Files\R\R-3.0.2\bin\i386")
    If Directory.Exists(rPath) = False Then
        Throw New DirectoryNotFoundException(String.Format("Could not found the specified path to the directory containing R.dll: {0}", rPath))
    End If
    Dim newPath = String.Format("{0}{1}{2}", rPath, System.IO.Path.PathSeparator, oldPath)
    System.Environment.SetEnvironmentVariable("PATH", newPath)
End Sub
End Class
End Namespace

and

Imports RDotNet
Imports ConsoleApplication36.RDotNetSetup
Imports System.Collections.Generic
Imports System.IO
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks

Module Module1

Sub Main()
SetupHelper.SetupPath()
Using engine As REngine = REngine.CreateInstance("RDotNet")
    engine.Initialize()
    Dim charVec As CharacterVector = engine.CreateCharacterVector({"Hello, R world!, .NET speaking"})
    engine.SetSymbol("greetings", charVec)
    engine.Evaluate("str(greetings)")
    Dim a As String() = engine.Evaluate("'Hi there .NET, from the R engine'").AsCharacter().ToArray()
    Console.WriteLine("R answered: '{0}'", a(0))
    Console.WriteLine("Press any key to exit the program")
    Console.ReadKey()
End Using
End Sub
End Module

I dont get an error, using the debugger at engine.Initialize my test stops running ( the green Start arrow reappears).

So I found another example that should (apparentely) works on VB.Net

Imports RDotNet
Imports System.IO
Imports System.Linq

Module Module1

Sub Main()
    Dim envPath = System.Environment.GetEnvironmentVariable("PATH")
    Dim rBinPath = "C:\Program Files\R\R-3.0.2\bin\i386"
    System.Environment.SetEnvironmentVariable("PATH", envPath & Path.PathSeparator & rBinPath)
    Dim engine As REngine = REngine.CreateInstance("RDotNet")
    Dim group1 As NumericVector = engine.CreateNumericVector(New Double() {30.02, 29.99, 30.11, 29.97, 30.01, 29.99})
    engine.SetSymbol("group1", group1)
    ' Direct parsing from R script.
    Dim s = "group2 <- c(29.89, 29.93, 29.72, 29.98, 30.02, 29.98)"
    Dim group2 = engine.Evaluate(s).AsNumeric()
    Dim testResult As GenericVector = engine.Evaluate("t.test(group1, group2)").AsList()
    Dim p As Double = testResult("p.value").AsNumeric().First()
    Console.WriteLine("Group1: [{0}]", String.Join(", ", group1))
    Console.WriteLine("Group2: [{0}]", String.Join(", ", group2))
    Console.WriteLine("P-value = {0:0.000}", p)
End Sub
End Module

Looks like the writer had the same problem and just left the engine.initialize. If I execute the code I get the error: "Value out of range" at Dim group1 As NumericVector = engine.CreateNumericVector(New Double() {30.02, 29.99, 30.11, 29.97, 30.01, 29.99}).

Anyone who could help me get a sample code for VB.NET to work? And explain me why i cannot initialize.

fyi: I checked the path and set all needed references.

Answer 1

Ok, hours of trying and discussion later it works. What I did:

1. I changed .net 4.5 to .net 4.0
2. I changed compiler settings from "AnyCPU" to "x86"
3. First line in the 'SetupPath()' is: System.Environment.SetEnvironmentVariable("R_HOME", "C:\Program Files\R\R-3.0.2")