gnu: Add julia-bfloat16s.

* gnu/packages/julia-xyz.scm (julia-bfloat16s): New variable.

Signed-off-by: Efraim Flashner <efraim@flashner.co.il>

gnu/packages/julia-xyz.scm

@@ -362,6 +362,34 @@ code easy by supplying a framework for writing and running groups of
 benchmarks as well as comparing benchmark results.")
     (license license:expat)))
 
+(define-public julia-bfloat16s
+  ;; Not tagged upstream
+  (let ((commit "ef6051e4308ed0c02f10168b99d226237e0ae33c")
+        (version "0.2.0"))
+    (package
+      (name "julia-bfloat16s")
+      (version version)
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/JuliaMath/BFloat16s.jl")
+               (commit commit)))
+         (file-name (git-file-name name version))
+         (sha256
+          (base32 "16sr578k4i47lhziri47nvspdrsni2wc1qjhs6hzffh9si6a7jfq"))))
+      (build-system julia-build-system)
+      (home-page "https://github.com/JuliaMath/BFloat16s.jl")
+      (synopsis "Define BFloat16 data type")
+      (description "This package defines the @code{BFloat16} data type.  The
+only currently available hardware implementation of this datatype are Google's
+Cloud TPUs.  As such, this package is suitable to evaluate whether using TPUs
+would cause precision problems for any particular algorithm, even without
+access to TPU hardware.  Note that this package is designed for functionality,
+not performance, so this package should be used for precision experiments
+only, not performance experiments.")
+      (license license:expat))))
+
 (define-public julia-bioalignments
   (package
     (name "julia-bioalignments")