Add fabs_pushforward to built-in derivatives

Fixes: #1162
vgvassilev · Dec 7, 2024 · dc77b3c · dc77b3c
1 parent 65330b5
commit dc77b3c
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diff --git a/include/clad/Differentiator/BuiltinDerivatives.h b/include/clad/Differentiator/BuiltinDerivatives.h
@@ -207,6 +207,11 @@ CUDA_HOST_DEVICE ValueAndPushforward<T, dT> abs_pushforward(T x, dT d_x) {
     return {-x, -d_x};
 }
 
+template <typename T, typename dT>
+CUDA_HOST_DEVICE ValueAndPushforward<T, dT> fabs_pushforward(T x, dT d_x) {
+  return abs_pushforward(x, d_x);
+}
+
 template <typename T, typename dT>
 CUDA_HOST_DEVICE ValueAndPushforward<T, dT> exp_pushforward(T x, dT d_x) {
   return {::std::exp(x), ::std::exp(x) * d_x};
@@ -413,6 +418,7 @@ using std::atan2_pushforward;
 using std::ceil_pushforward;
 using std::cos_pushforward;
 using std::exp_pushforward;
+using std::fabs_pushforward;
 using std::floor_pushforward;
 using std::fma_pullback;
 using std::fma_pushforward;

diff --git a/test/FirstDerivative/BuiltinDerivatives.C b/test/FirstDerivative/BuiltinDerivatives.C
@@ -286,6 +286,11 @@ float f16(float x) {
 //CHECK-NEXT:    return _t0.pushforward;
 //CHECK-NEXT: }
 
+double f17(double x) {
+  double y = std::fabs(x);
+  return 2*y;
+}
+
 int main () { //expected-no-diagnostics
   float f_result[2];
   double d_result[2];
@@ -377,6 +382,10 @@ int main () { //expected-no-diagnostics
 
   auto f16_darg0 = clad::differentiate(f16, 0);
   printf("Result is = %f\n", f16_darg0.execute(0.9)); //CHECK-EXEC: Result is = -2.294157
+
+  INIT_GRADIENT(f17);
+
+  TEST_GRADIENT(f17, /*numOfDerivativeArgs=*/1, -3, &d_result[0]); // CHECK-EXEC: {-2.00}
 
   return 0;
 }