Calling user-defined functions in R from within c#

using RDotNet;
 
// initialize R connection
var envPath = Environment.GetEnvironmentVariable("PATH");
 
// check the version and path on your computer
var rBinPath = @"C:Program FilesRR-2.14.1binx64";
 
Environment.SetEnvironmentVariable("PATH", envPath 
	+ System.IO.Path.PathSeparator + rBinPath);
 
// initialite REngine object
using (REngine engine = REngine.CreateInstance("RDotNet"))
{
	// Initializes settings.
	engine.Initialize();
 
	// define your function in R as multi-line string
	string myfuncstr = @"matrix_mult <- function(a,b){
	c = a %*% b;
	return(c);
	}";
 
	// embed your R function here
	Function matrix_mult = engine.Evaluate(myfuncstr).AsFunction();
 
        // create input matrices
        NumericMatrix a = engine.Evaluate(@"a <- matrix(c(1,4,2,5,3,6), nrow=2)").AsNumericMatrix();
        NumericMatrix b = engine.Evaluate(@"b <- matrix(c(1,4,2,5,3,6), nrow=3)").AsNumericMatrix();
 
	// call your R function from c#
	NumericMatrix c = engine.Evaluate(@"c <- matrix_mult(a,b)").AsNumericMatrix();
 
	// ...
}