gnu: Add r-cluster.

* gnu/packages/statistics.scm (r-cluster): New variable.

gnu/packages/statistics.scm

@@ -965,6 +965,28 @@ database.")
 transformations.")
     (license license:expat)))
 
+(define-public r-cluster
+  (package
+    (name "r-cluster")
+    (version "2.0.3")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "cluster" version))
+       (sha256
+        (base32
+         "03jfczb3dwg57f164pya0b762xgyswyb9a7s33lw9i0s5dq72ri8"))))
+    (build-system r-build-system)
+    (inputs
+     `(("gfortran" ,gfortran)))
+    (home-page "http://cran.r-project.org/web/packages/cluster")
+    (synopsis "Methods for data cluster analysis")
+    (description
+     "This package provides tools that are useful in finding groups in data.
+It is based on the methods described in Kaufman and Rousseeuw (1990) \"Finding
+Groups in Data\".")
+    (license license:gpl2+)))
+
 (define-public r-chron
   (package
     (name "r-chron")