Fix ZLT corner case

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: 3.13
-    - uses: actions/cache@v2
+    - uses: actions/cache@v4
       with:
         path: ~/.cache/pip
         key: ${{ hashFiles('setup.py') }}

integration/test_unittest.py

@@ -204,23 +204,24 @@ def test_zlt():
     logger.error(run)
 
 
-def _test_allzlt(monotonic):
-    vlist = {'RATE' : RangeVariable("RATE",1,10,log=False)}
+def _test_allzlt(monotonic,all=True):
+    vlist = {'RATE' : RangeVariable("RATE",1,10,log=False)} #From 1 to 10 included
     results = OrderedDict()
-    zlt = ZLTVariableExpander(vlist, results, {}, "RATE", "PPS", 1.01,all=True,monotonic=monotonic)
+    zlt = ZLTVariableExpander(vlist, results, {}, "RATE", "PPS", 1.01, all=all, monotonic=monotonic)
     it = iter(zlt)
     run = next(it)
     assert run["RATE"] == 10
     results[Run({'RATE' : 10})] = {'PPS':[3.0]}
     run = next(it)
     assert run["RATE"] == 3
     results[Run({'RATE' : 3})] = {'PPS':[3]}
-    run = next(it)
-    assert run["RATE"] == 2
-    results[Run({'RATE' : 2})] = {'PPS':[2]}
-    run = next(it)
-    assert run["RATE"] == 1
-    results[Run({'RATE' : 1})] = {'PPS':[1]}
+    if all:
+        run = next(it)
+        assert run["RATE"] == 2
+        results[Run({'RATE' : 2})] = {'PPS':[2]}
+        run = next(it)
+        assert run["RATE"] == 1
+        results[Run({'RATE' : 1})] = {'PPS':[1]}
     if not monotonic:
         run = next(it)
         assert run["RATE"] == 4
@@ -234,4 +235,6 @@ def _test_allzlt(monotonic):
 
 def test_allzlt():
     _test_allzlt(monotonic=True)
-    _test_allzlt(monotonic=False)
+    _test_allzlt(monotonic=False)
+    _test_allzlt(monotonic=True, all=False)
+    _test_allzlt(monotonic=False, all=False)

npf/expdesign/zltexp.py

@@ -38,10 +38,10 @@ def strlen(self):
         approx = int(len(self.expanded) * ceil(log2(len(self.input_values)) if (self.n_it <= 1) else self.n_tot_done/(self.n_it - 1)))
         max = len(self.expanded) * len(self.input_values)
         return f"~{approx}(max {max})"
+
 class ZLTVariableExpander(OptVariableExpander):
 
     def __init__(self, vlist:Dict[str,Variable], results, overriden, input, output, margin, all=False, perc=False, monotonic=False):
-
         self.output = output
         self.perc = perc
         self.monotonic = monotonic
@@ -127,15 +127,10 @@ def __next__(self):
 
             maybe_achievable_inputs = list(filter(lambda x : x <= max_r*self.margin, self.executable_values))
             left_to_try = set(maybe_achievable_inputs).difference(vals_for_current.keys())
-            if len(left_to_try) == 0:
-                #There's no more points to try, we could never find a ZLT
-                self.current = None
-                return self.__next__()
-
 
 
             #Step 3...K : try to get an acceptable rate. This step might be skipped if we got an acceptable rate already
-            if not acceptable_rates:
+            if left_to_try and not acceptable_rates:
                 #Try the rate below the min already tried rate - its drop count. For instance if we tried 70 last run but got 67 of throughput, try the rate below 64
                 min_input = min(vals_for_current.keys())
                 min_output = vals_for_current[min_input]