>From d6f9934721b818ce61e17ae60feb638ff57fbc9d Mon Sep 17 00:00:00 2001
From: Eric Bavier <address@hidden>
Date: Wed, 31 Jan 2018 13:55:37 -0600
Subject: [PATCH 1/2] gnu: Add QD.

* gnu/packages/multiprecision.scm (qd): New variable.
---
 gnu/packages/multiprecision.scm | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/gnu/packages/multiprecision.scm b/gnu/packages/multiprecision.scm
index b6d2d7f4a..e137fe388 100644
--- a/gnu/packages/multiprecision.scm
+++ b/gnu/packages/multiprecision.scm
@@ -4,6 +4,7 @@
 ;;; Copyright © 2015 Andreas Enge <address@hidden>
 ;;; Copyright © 2016 Nicolas Goaziou <address@hidden>
 ;;; Copyright © 2016 Jan Nieuwenhuizen <address@hidden>
+;;; Copyright © 2018 Eric Bavier <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -24,6 +25,7 @@
   #:use-module (guix licenses)
   #:use-module (gnu packages)
   #:use-module (gnu packages m4)
+  #:use-module (gnu packages gcc)
   #:use-module (guix packages)
   #:use-module (guix download)
   #:use-module (guix utils)
@@ -150,3 +152,41 @@ the other hand to obtain accurate results, thanks to multiple precision
 arithmetic.")
     (license lgpl2.1+)
     (home-page "https://perso.ens-lyon.fr/nathalie.revol/software.html")))
+
+(define-public qd
+  (package
+    (name "qd")
+    (version "2.3.18")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append "http://crd.lbl.gov/~dhbailey/mpdist/qd-"
+                                  version ".tar.gz"))
+              (sha256
+               (base32
+                "0vkihcj9fyv2cycq8515713gbs3yskhmivy8bznvx72i6ddnn2c1"))))
+    (build-system gnu-build-system)
+    (native-inputs
+     `(("gfortran" ,gfortran)))
+    (arguments
+     `(#:configure-flags `("--disable-enable_fma" ;weird :/
+                           "--enable-shared"
+                           ,,@(if (string-prefix? "aarch64"
+                                                  (or (%current-target-system)
+                                                      (%current-system)))
+                                  ;; XXX: The qd_test test fails numerical
+                                  ;; accuracy checks for 'dd_real::exp()' on
+                                  ;; aarch64 with GCC 5.4 at -O2.  Disabling
+                                  ;; expensive optimizations lets it pass.
+                                  '("CXXFLAGS=-O3 -fno-expensive-optimizations")
+                                  '("CXXFLAGS=-O3")))))
+    (home-page "http://crd-legacy.lbl.gov/~dhbailey/mpdist/")
+    (synopsis "Double-double and quad-double library")
+    (description "This package supports both a double-double
+datatype (approx. 32 decimal digits) and a quad-double datatype (approx. 64
+decimal digits).  The computational library is written in C++.  Both C++ and
+Fortran-90 high-level language interfaces are provided to permit one to
+convert an existing C++ or Fortran-90 program to use the library with only
+minor changes to the source code.  In most cases only a few type statements
+and (for Fortran-90 programs) read/write statements need to be changed.  PSLQ
+and numerical quadrature programs are included.")
+    (license bsd-3)))
-- 
2.15.1