Merge pull request #4211 from pleroy/Stuff

A bunch of improvement that were made while looking at plotting

Author: pleroy

base/traits.hpp

@@ -51,9 +51,29 @@ struct other_type<T2, T1, T2> {
   using type = T1;
 };
 
+template<typename... Ts>
+struct tail;
+
+template<typename T>
+struct tail<T> {
+  using type = T;
+  static constexpr T value(T t) {
+    return t;
+  }
+};
+
+template<typename T, typename... Ts>
+struct tail<T, Ts...> {
+  using type = typename tail<Ts...>::type;
+  static constexpr type value(T, Ts... ts) {
+    return tail<Ts...>::value(ts...);
+  }
+};
+
 }  // namespace internal
 
 using internal::all_different_v;
+using internal::tail;
 
 // True if and only if U is an instance of T.
 template<template<typename...> typename T, typename U>
@@ -79,6 +99,9 @@ inline constexpr bool is_same_template_v =
 template<typename T, typename T1, typename T2>
 using other_type_t = typename internal::other_type<T, T1, T2>::type;
 
+template<typename... Ts>
+using tail_t = typename internal::tail<Ts...>::type;
+
 }  // namespace _traits
 }  // namespace base
 }  // namespace principia

benchmarks/planetarium_benchmark.cpp

@@ -330,7 +330,6 @@ void BM_PlanetariumPlotMethod3(
         satellites.goes_8_trajectory(),
         satellites.goes_8_trajectory().begin(),
         satellites.goes_8_trajectory().end(),
-        now,
         /*t_max=*/InfiniteFuture,
         /*reverse=*/false,
         /*add_point=*/

geometry/conformal_map_body.hpp

@@ -4,6 +4,7 @@
 
 #include "geometry/homothecy.hpp"
 #include "quantities/elementary_functions.hpp"
+#include "quantities/serialization.hpp"
 
 namespace principia {
 namespace geometry {
@@ -12,6 +13,7 @@ namespace internal {
 
 using namespace principia::geometry::_homothecy;
 using namespace principia::quantities::_elementary_functions;
+using namespace principia::quantities::_serialization;
 
 template<typename Scalar, typename FromFrame, typename ToFrame>
 Scalar ConformalMap<Scalar, FromFrame, ToFrame>::scale() const {
@@ -87,7 +89,8 @@ ConformalMap<Scalar, FromFrame, ToFrame>::ReadFromMessage(
 template<typename Scalar, typename FromFrame, typename ToFrame>
 void ConformalMap<Scalar, FromFrame, ToFrame>::WriteToMessage(
     not_null<serialization::ConformalMap*> const message) const {
-  scale_.WriteToMessage(message->mutable_scale());
+  DoubleOrQuantitySerializer<Scalar, serialization::ConformalMap>::
+      WriteToMessage(scale_, message);
   quaternion_.WriteToMessage(message->mutable_quaternion());
 }
 
@@ -96,8 +99,10 @@ ConformalMap<Scalar, FromFrame, ToFrame>
 ConformalMap<Scalar, FromFrame, ToFrame>::ReadFromMessage(
     serialization::ConformalMap const& message)
   requires serializable<FromFrame> && serializable<ToFrame> {
-  return ConformalMap(Scalar::ReadFromMessage(message.scale()),
-                      Quaternion::ReadFromMessage(message.quaternion()));
+  return ConformalMap(
+      DoubleOrQuantitySerializer<Scalar, serialization::ConformalMap>::
+          ReadFromMessage(message),
+      Quaternion::ReadFromMessage(message.quaternion()));
 }
 
 template<typename Scalar, typename FromFrame, typename ToFrame>

geometry/grassmann_body.hpp

@@ -337,21 +337,16 @@ Vector<Product<LScalar, RScalar>, Frame> operator*(
       Cross(left.coordinates(), right.coordinates()));
 }
 
-// Implementation from [Kah06], §12 "Mangled Angles", p. 47.
 template<typename LScalar, typename RScalar, typename Frame>
 Angle AngleBetween(Vector<LScalar, Frame> const& v,
                    Vector<RScalar, Frame> const& w) {
-  auto const v_norm_w = v * w.Norm();
-  auto const w_norm_v = w * v.Norm();
-  return 2 * ArcTan((v_norm_w - w_norm_v).Norm(), (v_norm_w + w_norm_v).Norm());
+  return AngleBetween(v.coordinates(), w.coordinates());
 }
 
 template<typename LScalar, typename RScalar, typename Frame>
 Angle AngleBetween(Bivector<LScalar, Frame> const& v,
                    Bivector<RScalar, Frame> const& w) {
-  auto const v_norm_w = v * w.Norm();
-  auto const w_norm_v = w * v.Norm();
-  return 2 * ArcTan((v_norm_w - w_norm_v).Norm(), (v_norm_w + w_norm_v).Norm());
+  return AngleBetween(v.coordinates(), w.coordinates());
 }
 
 template<typename LScalar, typename RScalar, typename PScalar, typename Frame>

geometry/r3_element.hpp

@@ -210,12 +210,18 @@ template<typename LScalar, typename RScalar>
 Product<LScalar, RScalar> Dot(R3Element<LScalar> const& left,
                               R3Element<RScalar> const& right);
 
+// The result is in [0, π]; the function is commutative.
+template<typename LScalar, typename RScalar>
+Angle AngleBetween(R3Element<LScalar> const& left,
+                   R3Element<RScalar> const& right);
+
 // Returns the `i`th basis vector, whose `i`th coordinate is 1, and whose
 // other coordinates are 0.  `i` must be in [0, 2].
 R3Element<double> BasisVector(int i);
 
 }  // namespace internal
 
+using internal::AngleBetween;
 using internal::BasisVector;
 using internal::Cross;
 using internal::Dot;

geometry/r3_element_body.hpp

@@ -486,6 +486,16 @@ Product<LScalar, RScalar> Dot(R3Element<LScalar> const& left,
   return left.x * right.x + left.y * right.y + left.z * right.z;
 }
 
+// Implementation from [Kah06], §12 "Mangled Angles", p. 47.
+template<typename LScalar, typename RScalar>
+Angle AngleBetween(R3Element<LScalar> const& left,
+                   R3Element<RScalar> const& right) {
+  auto const left_norm_right = left * right.Norm();
+  auto const right_norm_left = right * left.Norm();
+  return 2 * ArcTan((left_norm_right - right_norm_left).Norm(),
+                    (left_norm_right + right_norm_left).Norm());
+}
+
 inline R3Element<double> BasisVector(int const i) {
   DCHECK_GE(i, 0) << i;
   DCHECK_LT(i, 3) << i;

geometry/space_transformations.hpp

@@ -30,6 +30,7 @@ using Similarity =
 
 }  // namespace internal
 
+using internal::DoubleConformalMap;
 using internal::RigidTransformation;
 using internal::Similarity;
 

ksp_plugin/interface_planetarium.cpp

@@ -155,7 +155,6 @@ void __cdecl principia__PlanetariumPlotFlightPlanSegment(
         *segment,
         segment->begin(),
         segment->end(),
-        plugin->CurrentTime(),
         t_max == nullptr ? InfiniteFuture : FromGameTime(*plugin, *t_max),
         /*reverse=*/false,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
@@ -188,7 +187,6 @@ void __cdecl principia__PlanetariumPlotPrediction(
       *prediction,
       prediction->begin(),
       prediction->end(),
-      plugin->CurrentTime(),
       t_max == nullptr ? InfiniteFuture : FromGameTime(*plugin, *t_max),
       /*reverse=*/false,
       [vertices, vertex_count](ScaledSpacePoint const& vertex) {
@@ -245,7 +243,6 @@ void __cdecl principia__PlanetariumPlotPsychohistory(
         trajectory,
         trajectory.lower_bound(desired_first_time),
         psychohistory->end(),
-        /*now=*/plugin->CurrentTime(),
         t_max == nullptr ? InfiniteFuture : FromGameTime(*plugin, *t_max),
         /*reverse=*/true,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
@@ -303,7 +300,6 @@ void __cdecl principia__PlanetariumPlotCelestialPastTrajectory(
         celestial_trajectory,
         first_time,
         /*last_time=*/plugin->CurrentTime(),
-        /*now=*/plugin->CurrentTime(),
         /*reverse=*/true,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
           vertices[(*vertex_count)++] = vertex;
@@ -362,7 +358,6 @@ void __cdecl principia__PlanetariumPlotCelestialFutureTrajectory(
         celestial_trajectory,
         /*first_time=*/plugin->CurrentTime(),
         /*last_time=*/final_time,
-        /*now=*/plugin->CurrentTime(),
         /*reverse=*/false,
         [vertices, vertex_count](ScaledSpacePoint const& vertex) {
           vertices[(*vertex_count)++] = vertex;
@@ -401,7 +396,6 @@ void __cdecl principia__PlanetariumPlotEquipotential(
       equipotential,
       equipotential.front().time,
       equipotential.back().time,
-      plugin->CurrentTime(),
       /*reverse=*/false,
       [vertices, vertex_count](ScaledSpacePoint const& vertex) {
         vertices[(*vertex_count)++] = vertex;

ksp_plugin/planetarium.cpp

@@ -269,7 +269,6 @@ void Planetarium::PlotMethod3(
     Trajectory<Barycentric> const& trajectory,
     DiscreteTrajectory<Barycentric>::iterator begin,
     DiscreteTrajectory<Barycentric>::iterator end,
-    Instant const& now,
     Instant const& t_max,
     bool const reverse,
     std::function<void(ScaledSpacePoint const&)> const& add_point,
@@ -282,7 +281,7 @@ void Planetarium::PlotMethod3(
   auto const last_time =
       std::min({last->time, plotting_frame_->t_max(), t_max});
   PlotMethod3(
-      trajectory, begin_time, last_time, now, reverse, add_point, max_points);
+      trajectory, begin_time, last_time, reverse, add_point, max_points);
 }
 
 std::vector<Sphere<Navigation>> Planetarium::ComputePlottableSpheres(

ksp_plugin/planetarium.hpp

@@ -130,7 +130,6 @@ class Planetarium {
       Trajectory<Barycentric> const& trajectory,
       DiscreteTrajectory<Barycentric>::iterator begin,
       DiscreteTrajectory<Barycentric>::iterator end,
-      Instant const& now,
       Instant const& t_max,
       bool reverse,
       std::function<void(ScaledSpacePoint const&)> const& add_point,
@@ -143,7 +142,6 @@ class Planetarium {
       Trajectory<Frame> const& trajectory,
       Instant const& first_time,
       Instant const& last_time,
-      Instant const& now,
       bool reverse,
       std::function<void(ScaledSpacePoint const&)> const& add_point,
       int max_points,

ksp_plugin/planetarium_body.hpp

@@ -53,7 +53,6 @@ void Planetarium::PlotMethod3(
     Trajectory<Frame> const& trajectory,
     Instant const& first_time,
     Instant const& last_time,
-    Instant const& now,
     bool const reverse,
     std::function<void(ScaledSpacePoint const&)> const& add_point,
     int const max_points,