From 85fead620edb4dfc6e0ce4de4f3f69cb21eb7550 Mon Sep 17 00:00:00 2001
From: Daniel Sharp <dannys4@mit.edu>
Date: Sun, 10 Sep 2023 14:16:55 -0400
Subject: [PATCH] Add plenty of rootfinding tests

---
 tests/Test_RootFinding.cpp | 59 ++++++++++++++++++++++++++++++--------
 1 file changed, 47 insertions(+), 12 deletions(-)

diff --git a/tests/Test_RootFinding.cpp b/tests/Test_RootFinding.cpp
index 369a237a..5bfd4b0c 100644
--- a/tests/Test_RootFinding.cpp
+++ b/tests/Test_RootFinding.cpp
@@ -22,39 +22,74 @@ TEST_CASE( "RootFindingUtils", "[RootFindingUtils]") {
     }
     auto identity = [](double x){return x;};
     auto sigmoid = [](double x){return 1./(std::exp(-x)+1);};
+    auto sigmoid_combo = [sigmoid](double x){return sigmoid(2*(x-1)) + 3*sigmoid(x*0.5) + 0.5*sigmoid(1.5*(x+1));};
     SECTION("FindBound lower linear") {
-        double xd = -1.;
+        double xd = -1.1;
         double yd = identity(xd);
         double xub = 2., yub = 2.;
         double xlb = 0., ylb = 0.;
-        FindBound<HostSpace>(false, yd, identity, xlb, ylb, xub, yub, 10'000);
+        FindBound<HostSpace>(false, yd, identity, xub, yub, xlb, ylb, 10'000);
         CheckFoundBounds(identity, xlb, xd, xub, ylb, yd, yub);
     }
     SECTION("FindBound upper linear") {
-        double xd = 1.;
+        double xd = 1.1;
         double yd = identity(xd);
         double xub = 0., yub = 0.;
         double xlb = -2., ylb = -2.;
-        FindBound<HostSpace>(true, yd, identity, xub, yub, xlb, ylb, 10'000);
+        FindBound<HostSpace>(true, yd, identity, xlb, ylb, xub, yub, 10'000);
         CheckFoundBounds(identity, xlb, xd, xub, ylb, yd, yub);
     }
     SECTION("FindBound lower sigmoid") {
         double xd = -0.5;
         double yd = sigmoid(xd);
-        double xub = 2., yub = 2.;
-        double xlb = 0., ylb = 0.;
-        FindBound<HostSpace>(false, yd, sigmoid, xlb, ylb, xub, yub, 10'000);
+        double xub =  2., yub = sigmoid(xub);
+        double xlb =  0., ylb = sigmoid(xlb);
+        FindBound<HostSpace>(false, yd, sigmoid, xub, yub, xlb, ylb, 10'000);
         CheckFoundBounds(sigmoid, xlb, xd, xub, ylb, yd, yub);
     }
     SECTION("FindBound upper sigmoid") {
         double xd = 0.5;
         double yd = sigmoid(xd);
-        double xub = 0., yub = 0.;
-        double xlb = -2., ylb = -2.;
-        FindBound<HostSpace>(true, yd, sigmoid, xub, yub, xlb, ylb, 10'000);
-        std::cout << "ylb = " << ylb << ", f(xlb) = " << sigmoid(xlb) << std::endl;
+        double xub =  0., yub = sigmoid(xub);
+        double xlb = -2., ylb = sigmoid(xlb);
+        FindBound<HostSpace>(true, yd, sigmoid, xlb, ylb, xub, yub, 10'000);
         CheckFoundBounds(sigmoid, xlb, xd, xub, ylb, yd, yub);
     }
-
+    SECTION("Test Inverse Linear, low x0") {
+        double xd = 0.5, yd = identity(xd);
+        double x0 = 0.0, xtol = 1e-5, ftol = 1e-5;
+        double xd_found = InverseSingleBracket<HostSpace>(yd, identity, x0, xtol, ftol);
+        CHECK( xd_found == Approx(xd).epsilon(2*xtol));
+    }
+    SECTION("Test Inverse Linear, high x0") {
+        double xd = 0.5, yd = identity(xd);
+        double x0 = 1.0, xtol = 1e-5, ftol = 1e-5;
+        double xd_found = InverseSingleBracket<HostSpace>(yd, identity, x0, xtol, ftol);
+        CHECK( xd_found == Approx(xd).epsilon(2*xtol));
+    }
+    SECTION("Test Inverse Sigmoid, low x0") {
+        double xd = 0.5, yd = sigmoid(xd);
+        double x0 = 0.0, xtol = 1e-5, ftol = 1e-5;
+        double xd_found = InverseSingleBracket<HostSpace>(yd, sigmoid, x0, xtol, ftol);
+        CHECK( xd_found == Approx(xd).epsilon(2*xtol));
+    }
+    SECTION("Test Inverse Sigmoid, high x0") {
+        double xd = 0.5, yd = sigmoid(xd);
+        double x0 = 1.0, xtol = 1e-5, ftol = 1e-5;
+        double xd_found = InverseSingleBracket<HostSpace>(yd, sigmoid, x0, xtol, ftol);
+        CHECK( xd_found == Approx(xd).epsilon(2*xtol));
+    }
+    SECTION("Test Inverse Sigmoid Combo, low x0") {
+        double xd = 0.5, yd = sigmoid_combo(xd);
+        double x0 = -5.0, xtol = 1e-5, ftol = 1e-5;
+        double xd_found = InverseSingleBracket<HostSpace>(yd, sigmoid_combo, x0, xtol, ftol);
+        CHECK( xd_found == Approx(xd).epsilon(2*xtol));
+    }
+    SECTION("Test Inverse Sigmoid Combo, high x0") {
+        double xd = 0.5, yd = sigmoid_combo(xd);
+        double x0 = 5.0, xtol = 1e-5, ftol = 1e-5;
+        double xd_found = InverseSingleBracket<HostSpace>(yd, sigmoid_combo, x0, xtol, ftol);
+        CHECK( xd_found == Approx(xd).epsilon(2*xtol));
+    }
 
 }
\ No newline at end of file