added math signals

src/acquisition.hpp

@@ -96,6 +96,9 @@ class Acquisition {
   /// instead of reappearing as a false low frequency. Cleared whenever the partition
   /// changes, since the group length is `time_stride`.
   std::vector<double> value_acc_;
+  /// The channels' values for the current *stored* slot, which the math channels are evaluated from
+  /// once the slot's samples have all been pushed. One entry per channel, refilled every slot.
+  std::vector<f32> math_sample_;
   std::vector<std::uint64_t> value_acc_n_;
   double time_acc_ = 0.0;
   std::uint64_t time_acc_n_ = 0;