close #8269: grow arrays incrementally by factors of 1.5 rather than 2

JuliaLang · May 10, 2016 · eb8a084 · eb8a084
1 parent c9d4051
commit eb8a084
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/src/array.c b/src/array.c
@@ -631,9 +631,9 @@ JL_DLLEXPORT void jl_array_grow_end(jl_array_t *a, size_t inc)
     // optimized for the case of only growing and shrinking at the end
     size_t alen = jl_array_nrows(a);
     if ((alen + inc) > a->maxsize - a->offset) {
-        size_t newlen = a->maxsize==0 ? (inc<4?4:inc) : a->maxsize*2;
+        size_t newlen = a->maxsize < 2 ? (inc<4?4:inc) : (a->maxsize*3)>>1;
         while ((alen + inc) > newlen - a->offset)
-            newlen *= 2;
+            newlen = (newlen*3)>>1;
 
         newlen = limit_overallocation(a, alen, newlen, inc);
         array_resize_buffer(a, newlen, alen, a->offset);
@@ -692,9 +692,9 @@ JL_DLLEXPORT void jl_array_grow_beg(jl_array_t *a, size_t inc)
         size_t alen = a->nrows;
         size_t anb = alen*es;
         if (inc > (a->maxsize-alen)/2 - (a->maxsize-alen)/20) {
-            size_t newlen = a->maxsize==0 ? inc*2 : a->maxsize*2;
+            size_t newlen = a->maxsize < 2 ? inc*2 : (a->maxsize*3)>>1;
             while (alen+2*inc > newlen-a->offset)
-                newlen *= 2;
+                newlen = (newlen*3)>>1;
 
             newlen = limit_overallocation(a, alen, newlen, 2*inc);
             size_t center = (newlen - (alen + inc))/2;