gnu: Add r-squarem.

* gnu/packages/cran.scm (r-squarem): New variable.

gnu/packages/cran.scm

@@ -989,6 +989,29 @@ testing framework of Wald are generic and can therefore also be used in other
 contexts.")
     (license license:gpl2+)))
 
+(define-public r-squarem
+  (package
+    (name "r-squarem")
+    (version "2017.10-1")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "SQUAREM" version))
+       (sha256
+        (base32
+         "10xj26x7qjyvzndnbjl5krr9wabnb9cbrnp3m7xg673g8ddr12cv"))))
+    (properties `((upstream-name . "SQUAREM")))
+    (build-system r-build-system)
+    (home-page "http://www.jhsph.edu/agingandhealth/People/Faculty_personal_pages/Varadhan.html")
+    (synopsis "Squared Extrapolation Methods for Accelerating EM-Like Monotone Algorithms")
+    (description
+     "This package provides algorithms for accelerating the convergence of
+slow, monotone sequences from smooth, contraction mapping such as the EM
+algorithm.  It can be used to accelerate any smooth, linearly convergent
+acceleration scheme.  A tutorial style introduction to this package is
+available in a vignette.")
+    (license license:gpl2+)))
+
 (define-public r-lava
   (package
     (name "r-lava")