From 0531f339e851528167b190207230162afb410d9d Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Wed, 31 Jan 2024 14:16:40 -0500
Subject: [PATCH] Use ran1 instead of random_number().

---
 lib/superfox/ran1.f90     | 28 ++++++++++++++++++++++++++++
 lib/superfox/synctest.f90 |  9 ++++++---
 2 files changed, 34 insertions(+), 3 deletions(-)
 create mode 100644 lib/superfox/ran1.f90

diff --git a/lib/superfox/ran1.f90 b/lib/superfox/ran1.f90
new file mode 100644
index 000000000..b09b9baba
--- /dev/null
+++ b/lib/superfox/ran1.f90
@@ -0,0 +1,28 @@
+FUNCTION ran1(idum)
+  INTEGER idum,IA,IM,IQ,IR,NTAB,NDIV
+  REAL ran1,AM,EPS,RNMX
+  PARAMETER (IA=16807,IM=2147483647,AM=1./IM,IQ=127773,IR=2836,    &
+       NTAB=32,NDIV=1+(IM-1)/NTAB,EPS=1.2e-7,RNMX=1.-EPS)
+  INTEGER j,k,iv(NTAB),iy
+  SAVE iv,iy
+  DATA iv /NTAB*0/, iy /0/
+  if (idum.le.0.or.iy.eq.0) then
+     idum=max(-idum,1)
+     do j=NTAB+8,1,-1
+        k=idum/IQ
+        idum=IA*(idum-k*IQ)-IR*k
+        if (idum.lt.0) idum=idum+IM
+        if (j.le.NTAB) iv(j)=idum
+     enddo
+     iy=iv(1)
+  endif
+  k=idum/IQ
+  idum=IA*(idum-k*IQ)-IR*k
+  if (idum.lt.0) idum=idum+IM
+  j=1+iy/NDIV
+  iy=iv(j)
+  iv(j)=idum
+  ran1=min(AM*iy,RNMX)
+
+  return
+END FUNCTION ran1
diff --git a/lib/superfox/synctest.f90 b/lib/superfox/synctest.f90
index 916caaee3..2e57c1713 100644
--- a/lib/superfox/synctest.f90
+++ b/lib/superfox/synctest.f90
@@ -12,7 +12,7 @@ program synctest
   complex clo(NMAX)                      !Complex Local Oscillator
   complex cnoise(NMAX)                   !Complex noise
   complex crcvd(NMAX)                    !Signal as received
-  real xdat(ND)                          !Temporary: for generating idat
+!  real xdat(ND)                          !Temporary: for generating idat
   integer*1 idat(ND)                     !Encoded data, 7-bit integers
   integer*1 jdat(ND)                     !Recovered hard-decision symbols
   character fname*17,arg*12
@@ -39,9 +39,11 @@ program synctest
   rms=100.
   fsample=12000.0                   !Sample rate (Hz)
   baud=12000.0/nsps                 !Keying rate, 11.719 baud for nsps=1024
+  idummy=0
 
-  call random_number(xdat)
-  idat=int(127.9999*xdat)
+  do i=1,ND
+     idat(i)=128*ran1(idummy)
+  enddo
   
   h=default_header(12000,NMAX)
   fname='000000_000001.wav'
@@ -99,3 +101,4 @@ program synctest
   include 'gen_sfox.f90'
   include 'sync_sf.f90'
   include 'hard_symbols.f90'
+  include 'ran1.f90'