From e842004bdad27384a94a3cd395746332cf0eae12 Mon Sep 17 00:00:00 2001
From: cianciosa <cianciosamr@ornl.gov>
Date: Thu, 9 Jan 2025 12:30:46 -0500
Subject: [PATCH] Add trig idenitry reduction.

---
 graph_framework/arithmetic.hpp  | 14 ++++++++++++++
 graph_tests/arithmetic_test.cpp | 13 +++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/graph_framework/arithmetic.hpp b/graph_framework/arithmetic.hpp
index 01d2ab3..429d37d 100644
--- a/graph_framework/arithmetic.hpp
+++ b/graph_framework/arithmetic.hpp
@@ -520,6 +520,20 @@ namespace graph {
                                 pow(prm->get_left(), pl->get_right()));
                     }
                 }
+
+//  cos(x)^2 + sin(x)^2 -> 1
+//  sin(x)^2 + cos(x)^2 -> 1
+                auto plrc = constant_cast(pl->get_right());
+                if (plrc.get() && plrc->is(static_cast<T> (2.0))) {
+                    auto pls = sin_cast(pl->get_left());
+                    auto prc = cos_cast(pr->get_left());
+                    auto plc = cos_cast(pl->get_left());
+                    auto prs = sin_cast(pr->get_left());
+                    if ((pls.get() && prc.get() && pls->get_arg()->is_match(prc->get_arg())) ||
+                        (plc.get() && prs.get() && plc->get_arg()->is_match(prs->get_arg()))) {
+                        return one<T, SAFE_MATH> ();
+                    }
+                }
             }
 
 //  (a/y)^e + b/y^e -> (a^2 + b)/(y^e)
diff --git a/graph_tests/arithmetic_test.cpp b/graph_tests/arithmetic_test.cpp
index 3417578..1d25ed4 100644
--- a/graph_tests/arithmetic_test.cpp
+++ b/graph_tests/arithmetic_test.cpp
@@ -433,6 +433,19 @@ template<jit::float_scalar T> void test_add() {
     assert(common_power_factor4_cast->get_left()->is_match(var_b*var_b +
                                                            var_c*var_c) &&
            "Expected b^2 + c^2 on the left.");
+
+//  cos(x)^2 + sin(x)^2 -> 1
+    auto trig = graph::cos(var_a)*graph::cos(var_a)
+              + graph::sin(var_a)*graph::sin(var_a);
+    auto trig_cast = graph::constant_cast(trig);
+    assert(trig_cast.get() && "Expected a constant node.");
+    assert(trig_cast->is(static_cast<T> (1.0)) && "Expected 1.");
+//  sin(x)^2 + cos(x)^2 -> 1
+    auto trig2 = graph::sin(var_a)*graph::sin(var_a)
+               + graph::cos(var_a)*graph::cos(var_a);
+    auto trig2_cast = graph::constant_cast(trig2);
+    assert(trig2_cast.get() && "Expected a constant node.");
+    assert(trig2_cast->is(static_cast<T> (1.0)) && "Expected 1.");
 }
 
 //------------------------------------------------------------------------------
-- 
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