From 45dac5bd18295fd16da6ae3177f75416d3869ed7 Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Sun, 2 Aug 2020 09:42:22 -0400
Subject: [PATCH] Change random number generation in qra66sim so results are
 exactly repeateble.

---
 lib/gran.c                 | 6 ++++++
 lib/qra/qra66/qra66sim.f90 | 6 ++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/gran.c b/lib/gran.c
index 24b986503..ac41c7fe4 100644
--- a/lib/gran.c
+++ b/lib/gran.c
@@ -26,3 +26,9 @@ float gran_()
   iset++;
   return v2*fac;
 }
+
+/* Generates evenly distributed numbers between 0 and 1. */
+float rran_()
+{
+  return (float)rand()/(float)RAND_MAX;
+}
diff --git a/lib/qra/qra66/qra66sim.f90 b/lib/qra/qra66/qra66sim.f90
index a482e4cc3..0e1910490 100644
--- a/lib/qra/qra66/qra66sim.f90
+++ b/lib/qra/qra66/qra66sim.f90
@@ -110,15 +110,13 @@ program qra66sim
            a=0.
            if(x.lt.3.0) then                          !Cutoff beyond x=3
               a=sqrt(1.111/(1.0+x*x)-0.1)             !Lorentzian amplitude
-              call random_number(r1)
-              phi1=twopi*r1                           !Random phase
+              phi1=twopi*rran()                       !Random phase
               z=a*cmplx(cos(phi1),sin(phi1))
            endif
            cspread(i)=z
            z=0.
            if(x.lt.3.0) then                !Same thing for negative freqs
-              call random_number(r2)
-              phi2=twopi*r2
+              phi2=twopi*rran()
               z=a*cmplx(cos(phi2),sin(phi2))
            endif
            cspread(NFFT-i)=z