01/02: gnu: Add r-pdist.

[Ricardo Wurmus]

rekado pushed a commit to branch master
in repository guix.

commit 1ab867bebb78bb2efbe8e33c12e5f17b0e16a950
Author: Ricardo Wurmus <address@hidden>
Date:   Fri Oct 20 10:49:32 2017 +0200

    gnu: Add r-pdist.
    
    * gnu/packages/cran.scm (r-pdist): New variable.
---
 gnu/packages/cran.scm | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/gnu/packages/cran.scm b/gnu/packages/cran.scm
index e00a8a4..dba294c 100644
--- a/gnu/packages/cran.scm
+++ b/gnu/packages/cran.scm
@@ -1217,3 +1217,27 @@ initial data set and then applied to other data sets.  
The resulting design
 matrices can then be used as inputs into statistical or machine learning
 models.")
     (license license:gpl2)))
+
+(define-public r-pdist
+  (package
+    (name "r-pdist")
+    (version "1.2")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "pdist" version))
+       (sha256
+        (base32
+         "18nd3mgad11f2zmwcp0w3sxlch4a9y6wp8dfdyzvjn7y4b4bq0dd"))))
+    (build-system r-build-system)
+    (home-page "https://github.com/jeffwong/pdist";)
+    (synopsis "Partitioned distance function")
+    (description
+     "Pdist computes the euclidean distance between rows of a matrix X and
+rows of another matrix Y.  Previously, this could be done by binding the two
+matrices together and calling @code{dist}, but this creates unnecessary
+computation by computing the distances between a row of X and another row of
+X, and likewise for Y.  Pdist strictly computes distances across the two
+matrices, not within the same matrix, making computations significantly faster
+for certain use cases.")
+    (license license:gpl3+)))