From f47e15a1d6ebb6c6924152b635c8f0d97193427d Mon Sep 17 00:00:00 2001
From: Kristin <kberry@usgs.gov>
Date: Wed, 1 Jul 2020 15:14:50 -0700
Subject: [PATCH] Add code to States to not interpolate if an exact solution
exists (#374)
* Update format of range conversion coefficients isd output to include a separate list for times. Also update driver, test data, and remove unneeded semicolons
* Fix documentaion error
* fix other documentation error
* Add code to states to not interpolate if there is already an exact value for a time (solves divide by 0 error in interpolation code.)
* Updated to be more efficient
* lower_bound can also return the last elt. don't do that
* Added test for when no interpolation is needed for getState
---
src/States.cpp | 14 +++++++++++---
tests/ctests/StatesTests.cpp | 25 +++++++++++++++++++++++++
2 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/src/States.cpp b/src/States.cpp
index b63629d..4c3d183 100644
--- a/src/States.cpp
+++ b/src/States.cpp
@@ -111,6 +111,16 @@ namespace ale {
State States::getState(double time, PositionInterpolation interp) const {
+
+
+ // If time is in times, don't need to interpolate!
+ auto candidate_time = std::lower_bound(m_ephemTimes.begin(), m_ephemTimes.end(), time);
+
+ if ( (candidate_time != m_ephemTimes.end()) && (*candidate_time == time) ) {
+ int index = std::distance(m_ephemTimes.begin(), candidate_time);
+ return m_states[index];
+ }
+
if (m_ephemTimes.size() > 1) {
int lowerBound = interpolationIndex(m_ephemTimes, time);
// try to copy the surrounding 8 points as that's the most possibly needed
@@ -132,7 +142,6 @@ namespace ale {
}
Vec3d position, velocity;
-
if ( interp == LINEAR || (interp == SPLINE && !hasVelocity())) {
position = {interpolate(xs, interpTimes, time, interp, 0),
interpolate(ys, interpTimes, time, interp, 0),
@@ -145,7 +154,6 @@ namespace ale {
else if (interp == SPLINE && hasVelocity()){
// Do hermite spline if velocities are available
double baseTime = (interpTimes.front() + interpTimes.back()) / 2;
-
std::vector<double> scaledEphemTimes;
for(unsigned int i = 0; i < interpTimes.size(); i++) {
scaledEphemTimes.push_back(interpTimes[i] - baseTime);
@@ -169,7 +177,7 @@ namespace ale {
return State(position, velocity);
}
else { // Here we have: only 1 time and 1 state, so just return the only state.
- return State(m_states[0]);
+ return m_states[0];
}
}
diff --git a/tests/ctests/StatesTests.cpp b/tests/ctests/StatesTests.cpp
index 43b709f..72ec475 100644
--- a/tests/ctests/StatesTests.cpp
+++ b/tests/ctests/StatesTests.cpp
@@ -347,6 +347,31 @@ TEST(StatesTest, OneStateWithVelocity) {
EXPECT_NEAR(result.velocity.z, -1.0, 1e-6);
}
+TEST(StatesTest, NoInterpNeeded) {
+ std::vector<double> ephemTimes = {0.0, 1.0, 2.0};
+
+ std::vector<Vec3d> positions = {
+ Vec3d(5.0, 3.0, 0.0),
+ Vec3d(6.5, 4.0, 1.0),
+ Vec3d(15.0, 4.0, 5.0)};
+
+ std::vector<Vec3d> velocities = {
+ Vec3d(5.0, 3.0, 0.0),
+ Vec3d(7.0, 6.0, 1.0),
+ Vec3d(15.0, 4.0, 5.0)};
+
+
+ States testState(ephemTimes, positions, velocities);
+ State result = testState.getState(1.0);
+ EXPECT_NEAR(result.position.x, 6.5, 1e-5);
+ EXPECT_NEAR(result.position.y, 4.0, 1e-4);
+ EXPECT_NEAR(result.position.z, 1.0, 1e-5);
+ EXPECT_NEAR(result.velocity.x, 7.0, 1e-6);
+ EXPECT_NEAR(result.velocity.y, 6.0, 1e-6);
+ EXPECT_NEAR(result.velocity.z, 1.0, 1e-6);
+}
+
+
// This test checks to see if the minimized cache looks identical to ISIS's minimized cache for
// a Dawn IR image VIR_IR_1A_1_362681634_1 (located in dawnvir2isis's IR app test.)
// Values were obtained by adding strategic couts to SpicePosition.cpp, running spiceinit, and
--
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