message: super-minor naming change
diff: @@ -1446,8 +1446,7 @@ template <typename T> void ad_clear() {
  continue;
  Variable &v = it.value();
  v.grad = T();
  - ad_trace("ad_clear(): clearing gradient at intermediate "
  - "variable a%u (\"%s\")",
  + ad_trace("ad_clear(): clearing gradient at variable a%u (\"%s\")",
  index, v.label ? v.label : "unnamed");
  }
  