[#167] netmap: Fix reverse min agregator

The higher the price, the lower reverse min weight should be.
Previously nodes with 0 price had 0 weight which is a bit misleading.

Introduced in d71a0e0755.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

netmap/aggregator.go

@@ -156,11 +156,7 @@ func (a *meanIQRAgg) Compute() float64 {
 }
 
 func (r *reverseMinNorm) Normalize(w float64) float64 {
-	if w == 0 {
-		return 0
-	}
-
-	return r.min / w
+	return (r.min + 1) / (w + 1)
 }
 
 func (r *sigmoidNorm) Normalize(w float64) float64 {

netmap/json_tests/hrw_sort.json

@@ -146,19 +146,19 @@
     "select 3 nodes in 3 distinct countries, same placement": {
       "policy": {"replicas":[{"count":1,"selector":"Main"}],"containerBackupFactor":1,"selectors":[{"name":"Main","count":3,"clause":"DISTINCT","attribute":"Country","filter":"*"}],"filters":[]},
       "pivot": "Y29udGFpbmVySUQ=",
-      "result": [[0, 2, 3]],
+      "result": [ [ 5, 0, 7 ] ],
       "placement": {
         "pivot": "b2JqZWN0SUQ=",
-        "result": [[0, 2, 3]]
+        "result": [ [ 5, 0, 7 ] ]
       }
     },
     "select 6 nodes in 3 distinct countries, different placement": {
       "policy": {"replicas":[{"count":1,"selector":"Main"}],"containerBackupFactor":2,"selectors":[{"name":"Main","count":3,"clause":"DISTINCT","attribute":"Country","filter":"*"}],"filters":[]},
       "pivot": "Y29udGFpbmVySUQ=",
-      "result": [[0, 1, 2, 6, 3, 4]],
+      "result": [ [ 5, 4, 0, 1, 7, 2 ] ],
       "placement": {
         "pivot": "b2JqZWN0SUQ=",
-        "result": [[0, 1, 2, 6, 3, 4]]
+        "result": [ [ 5, 4, 0, 7, 2, 1 ] ]
       }
     }
   }