From 3bcb519ca17fad1d2a4c9ec94e02b797d2cda859 Mon Sep 17 00:00:00 2001
From: wukong <wukong@tjikko>
Date: Sat, 20 Dec 2025 18:14:42 -0800
Subject: added commented out alternate uptime prediction; changed to
 merge_meas() of t_meas[] estimate when t[before] == t[after], 	this provides
 a sub-second uncertainty when used with systime() 	and helps derived
 estimates converge; set shell script to use uncertainty based sleep time in
 main loop;

---
 ckt0.awk | 45 ++++++++++++++++++++++++++++-----------------
 ckt0.sh  |  5 ++---
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/ckt0.awk b/ckt0.awk
index dd83717..1c7ca6e 100644
--- a/ckt0.awk
+++ b/ckt0.awk
@@ -28,18 +28,17 @@ function merge_meas(est_val, est_unc, meas_val, meas_unc) {
 
 function sigfig(val, unc) {
 
-    ordmag_val = log10(val)
-    ordmag_unc = log10(unc)
+    omag_val = log10(val)
+    omag_unc = log10(unc)
 
-    ordmag_high = sqrt((ordmag_val)^2.0 + (ordmag_unc)^2.0)
-    ordmag_low = ((ordmag_val)^-1.0 + (ordmag_unc)^-1.0)^-1.0
-    ordmag_range = ordmag_high - ordmag_low
+    omag_high = sqrt((omag_val)^2.0 + (omag_unc)^2.0)
+    omag_low = ((omag_val)^-1.0 + (omag_unc)^-1.0)^-1.0
 
-    sigfig_unc = sprintf("%.f", ordmag_range)
-    sigfig_val = sprintf("%.f", sigfig_unc + 6.0)
+    sfig_unc = sprintf("%.f", sqrt((omag_high - omag_low)^2.0 + 6.0^2.0))
+    sfig_val = sprintf("%.f", sqrt(sfig_unc^2.0 + 6.0^2.0))
 
-    ofmt_val = "%." sigfig_val "g"
-    ofmt_unc = "%." sigfig_unc "g"
+    ofmt_val = "%." sfig_val "g"
+    ofmt_unc = "%." sfig_unc "g"
 
     return sprintf(ofmt_val OFS ofmt_unc, val, unc)
 
@@ -154,11 +153,7 @@ BEGIN {
     "uname" | getline uname
     close("uname")
 
-    #print("_systime_", systime())
-    #print("_boottime_", ck_boottime())
-
     # check ARGV for previous estimates
-    #print("ARGC:", ARGC)
     if (ARGC) {
         ARGV[1] ? t_prev[1] = ARGV[1] : t_prev[1] = 0.0
         ARGV[2] ? t_prev[2] = ARGV[2] : t_prev[2] = systime()
@@ -167,7 +162,6 @@ BEGIN {
         ARGV[5] ? t0_prev[1] = ARGV[5] : split(ck_boottime(uname), t0_prev)
         ARGV[6] ? t0_prev[2] = ARGV[6] : split(ck_boottime(uname), t0_prev)
     }
-    #print( t_prev[1], t_prev[2], t_up_prev[1], t_up_prev[2], t0_prev[1], t0_prev[2] )
 
     # check systime, check uptime, check systime again
     t_meas[1] = ck_time(uname)
@@ -179,7 +173,7 @@ BEGIN {
         t_meas[2] -= t_meas[1]
         t_meas[1] += 0.5*t_meas[2]
     } else {
-        t_meas[2] = 1.0
+        split(merge_meas(t_meas[1], 1.0, t_meas[2], 1.0), t_meas)
     }
     t_meas_str = sigfig(t_meas[1], t_meas[2])
 
@@ -190,19 +184,36 @@ BEGIN {
     # predict uptime based on dt, t_up(new) = t_up(old) + dt
     t_up_est[1] = t_up_prev[1] + dt[1]
     t_up_est[2] = t_up_prev[2] + dt[2]
+    t_up_est[2] += sqrt((t_up_est[1] - t_up_prev[1] - dt[1])^2.0)
+
+    # alt. prediction based on t0
+    t_up_alt[1] = t_meas[1] - t0_prev[1]
+    t_up_alt[2] = t_meas[2] + t0_prev[2]
+
+    # dt_up_alt
+    # dt_up_alt[1] = t_up_alt[1] - (t_prev[1] - t0_prev[1])
+    # dt_up_alt[2] = t_up_alt[2] + (t_prev[2] + t0_prev[2])
+
+    # merge alt. prediction
+    # t_up_alt[2] += sqrt((dt_up_alt[1] - dt[1])^2.0)
+    # t_up_alt[2] += sqrt((t_up_alt[1] - t_up_est[1])^2.0)
+    # t_up_est[2] += sqrt((t_up_est[1] - t_up_alt[1])^2.0)
+
+    # split(merge_meas(t_up_est[1], t_up_est[2], t_up_alt[1], t_up_alt[2]), t_up_est)
+    # t_up_est[2] += (1.0E-3*rand())^2.0
 
     # merge predicted and measured uptimes
     split(merge_meas(t_up_est[1], t_up_est[2], t_up_meas[1], t_up_meas[2]), t_up_est)
-    t_up_est[2] = sqrt( t_up_est[2]^2.0 + (t_up_est[1] - t_up_prev[1] - dt[1])^2.0 )
     t_up_est_str = sigfig(t_up_est[1], t_up_est[2])
 
     # evaluate measured boot time, t0
     t0_est[1] = t_meas[1] - t_up_est[1]
     t0_est[2] = t_meas[2] + t_up_est[2]
+    t0_est[2] += sqrt((t0_est[1] - t0_prev[1])^2.0)
 
     # merge previous and updated boot time, t0
     split(merge_meas(t0_est[1], t0_est[2], t0_prev[1], t0_prev[2]), t0_est)
-    t0_est[2] = sqrt( t0_est[2]^2.0 + (t0_est[1] - t0_prev[1])^2.0 )
+
     t0_est_str = sigfig(t0_est[1], t0_est[2])
 
     print(t_meas_str, t_up_est_str, t0_est_str)
diff --git a/ckt0.sh b/ckt0.sh
index 88fbb78..cf54ad0 100644
--- a/ckt0.sh
+++ b/ckt0.sh
@@ -25,10 +25,9 @@ for N in $(seq 0 10080) ; do
     printf "${N} ${t0_est}\n" | column -t
     t0_est=$( mawk -f ckt0.awk ${t0_est} | tail -n2 )
     #mawk -f ckt0.awk
-    sleep $( mawk 'BEGIN {print(sqrt( rand()^2.0 + 1.0 ))}' )
+    #sleep $( mawk 'BEGIN {print(sqrt( rand()^2.0 + 1.0 ))}' )
     #sleep $( echo $t0_est | mawk '{print(sqrt( ((60.0*$4)/(60.0 + $4))^2.0 + rand()^2.0 ))}' )
-    #sleep $( echo $t0_est | mawk '{print(sqrt( ($2)^2.0 + ($4)^2.0 + ($6)^2.0 + rand()^2.0 ))}' )
-    #sleep $( echo $t0_est | mawk '{print( 10.0 - (systime() - $5)%10.0 + 0.5*rand()^2.0 )}' )
+    sleep $( echo $t0_est | mawk '{print( sqrt($2^2.0 + $4^2.0 + $6^2.0 + rand()^2.0)%30.0 )}' )
 
 done
 
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