fix Floatbuffer.reserve

src/adam/floatbuffer.ml

@@ -19,7 +19,7 @@ let reserve t new_len =
   if capacity < new_len then
     begin
       let array = Array1.create Float32 C_layout (capacity * 2) in
-      Array1.blit t.array array;
+      Array1.blit t.array (Array1.sub array 0 capacity);
       t.array <- array;
     end;
   t.length <- new_len;