add test trial logging

main.lua

@@ -102,6 +102,7 @@ local log_map = {
     adam_std = 7,
     weight_mean = 8,
     weight_std = 9,
+    test_trial = 10,
 }
 
 local function log_csv(t)
@@ -597,8 +598,10 @@ local function learn_from_epoch()
 
     --for _, v in ipairs(trial_rewards) do insert(all_rewards, v) end
 
+    local current_cost = trial_rewards[0] -- may be nil!
+
     if cfg.unperturbed_trial then
-        local nth_place = unperturbed_rank(trial_rewards, trial_rewards[0])
+        local nth_place = unperturbed_rank(trial_rewards, current_cost)
 
         -- a rank of 1 means our gradient is uninformative.
         print(("test trial: %d out of %d"):format(nth_place, #trial_rewards))
@@ -723,6 +726,7 @@ local function learn_from_epoch()
         adam_std = momstep_dev,
         weight_mean = weight_mean,
         weight_std = weight_std,
+        test_trial = current_cost or 0,
     }
 
     -- trying a heuristic...