fix error with get_loss_function and set_minmax function

VowpalWabbit · Jan 19, 2023 · 0a1a075 · 0a1a075
1 parent 40ba14c
commit 0a1a075
Showing 1 changed file with 9 additions and 6 deletions.
diff --git a/vowpalwabbit/core/src/loss_functions.cc b/vowpalwabbit/core/src/loss_functions.cc
@@ -13,6 +13,7 @@
 #include <cfloat>
 #include <cmath>
 #include <cstdlib>
+#include <type_traits>
 
 namespace
 {
@@ -482,14 +483,18 @@ namespace VW
 std::unique_ptr<loss_function> get_loss_function(
     VW::workspace& all, const std::string& funcName, float function_parameter_0, float function_parameter_1)
 {
+  // For some loss functions, we want to know if all.set_minmax has been overwritten
+  // Check if the std::function object does not contain VW::details::noop_mm
+  using noop_mm_fn_ptr_type = typename std::add_pointer<decltype(VW::details::noop_mm)>::type;
+  auto* minmax_fptr = all.set_minmax.target<noop_mm_fn_ptr_type>();
+  bool set_minmax_is_not_noop = (minmax_fptr == nullptr || *minmax_fptr != VW::details::noop_mm);
+
   if (funcName == "squared" || funcName == "Huber") { return VW::make_unique<squaredloss>(); }
   else if (funcName == "classic") { return VW::make_unique<classic_squaredloss>(); }
   else if (funcName == "hinge") { return VW::make_unique<hingeloss>(all.logger); }
   else if (funcName == "logistic")
   {
-    // Check if the std::function object contains exactly VW::details::noop_mm
-    auto minmax_fptr = all.set_minmax.target<decltype(VW::details::noop_mm)>();
-    if (minmax_fptr == VW::details::noop_mm)
+    if (set_minmax_is_not_noop)
     {
       all.sd->min_label = -50;
       all.sd->max_label = 50;
@@ -503,9 +508,7 @@ std::unique_ptr<loss_function> get_loss_function(
   else if (funcName == "expectile") { return VW::make_unique<expectileloss>(function_parameter_0); }
   else if (funcName == "poisson")
   {
-    // Check if the std::function object contains exactly VW::details::noop_mm
-    auto minmax_fptr = all.set_minmax.target<decltype(VW::details::noop_mm)>();
-    if (minmax_fptr == VW::details::noop_mm)
+    if (set_minmax_is_not_noop)
     {
       all.sd->min_label = -50;
       all.sd->max_label = 50;