improve handling of gaps in distinctVals

Author: archmoj

src/lib/search.js

@@ -12,6 +12,7 @@
 var isNumeric = require('fast-isnumeric');
 var loggers = require('./loggers');
 var identity = require('./identity');
+var BADNUM = require('../constants/numerical').BADNUM;
 
 // don't trust floating point equality - fraction of bin size to call
 // "on the line" and ensure that they go the right way specified by
@@ -74,20 +75,39 @@ exports.distinctVals = function(valsIn) {
     var vals = valsIn.slice();  // otherwise we sort the original array...
     vals.sort(exports.sorterAsc);
 
-    var l = vals.length - 1;
-    var minDiff = (vals[l] - vals[0]) || 1;
-    var errDiff = minDiff / (l || 1) / 10000;
-    var v2 = [vals[0]];
+    var first;
+    for(first = 0; first < vals.length; first++) {
+        if(vals[first] !== BADNUM) break;
+    }
+
+    var last;
+    for(last = vals.length - 1; last > -1; last--) {
+        if(vals[last] !== BADNUM) break;
+    }
+
+    var minDiff = (vals[last] - vals[first]) || 1;
+    var errDiff = minDiff / ((last - first) || 1) / 10000;
+    var newVals = [];
+    var preV;
+    for(var i = first; i <= last; i++) {
+        var v = vals[i];
+        if(v === BADNUM) continue;
 
-    for(var i = 0; i < l; i++) {
         // make sure values aren't just off by a rounding error
-        if(vals[i + 1] > vals[i] + errDiff) {
-            minDiff = Math.min(minDiff, vals[i + 1] - vals[i]);
-            v2.push(vals[i + 1]);
+        var diff = v - preV;
+
+        if(preV === undefined) {
+            newVals.push(v);
+            preV = v;
+        } else if(diff > errDiff) {
+            minDiff = Math.min(minDiff, diff);
+
+            newVals.push(v);
+            preV = v;
         }
     }
 
-    return {vals: v2, minDiff: minDiff};
+    return {vals: newVals, minDiff: minDiff};
 };
 
 /**