experiments/STT-tensorflow
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[XLA] Fix implementation of acos(-1).

Browse Source 
At least on fp16, it was returning 0, when it should have returned pi.

PiperOrigin-RevId: 230834226
This commit is contained in:
Justin Lebar 2019-01-24 19:18:24 -08:00 committed by TensorFlower Gardener
parent 6291988afa
commit c00907e080
2 changed files with 8 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
tensorflow/compiler/xla/client/lib/math.cc
View File

@ -367,10 +367,13 @@ XlaOp RoundToEven(XlaOp x) {
// Trigonometric functions.
// acos(x) = 2 * atan(sqrt(1 - x^2) / (1 + x))
// acos(x) = 2 * atan(sqrt(1 - x^2) / (1 + x)) if x != -1
// pi if x == -1
XlaOp Acos(XlaOp x) {
return ScalarLike(x, 2.0) *
Atan2(Sqrt(ScalarLike(x, 1.0) - x * x), ScalarLike(x, 1.0) + x);
return Select(Ne(x, FullLike(x, -1)),
ScalarLike(x, 2.0) * Atan2(Sqrt(ScalarLike(x, 1.0) - x * x),
ScalarLike(x, 1.0) + x),
FullLike(x, M_PI));
}
// asin(x) = 2 * atan(x / (1 + sqrt(1 - x^2)))

6
tensorflow/compiler/xla/client/lib/math_exhaustive_test.cc
View File

@ -137,10 +137,7 @@ XLA_TEST_P(MathExhaustiveTest, DISABLED_ON_INTERPRETER(F16)) {
ComputeAndCompareR1<half>(&b, expected_result, {}, tc.error);
}
// TODO(jlebar): The following tests are missing.
//
// - Fails on -1 (returns 0 instead of pi).
// Testcase{"acos", Acos, std::acos}.set_skip_infs(),
// TODO(b/123355973): The following tests are missing.
//
// - Many failures.
// Testcase{"acosh", Acosh, std::acosh}.set_relaxed_nans(),
@ -170,6 +167,7 @@ INSTANTIATE_TEST_CASE_P(
.set_tolerance(0.1, 0.15)
.set_fewer_infs_ok(),
Testcase{"asin", Asin, std::asin}.set_skip_infs(),
Testcase{"acos", Acos, std::acos}.set_skip_infs(),
Testcase{"atan", Atan, std::atan},
Testcase{"tan", Tan, std::tan}.set_tolerance(0.05, 0.05),
}));