devtools/eigen
1
0
Fork 0
mirror of https://gitlab.com/libeigen/eigen.git synced 2026-04-10 11:34:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

Add support for Armv8.2-a __fp16

Browse Source 
Armv8.2-a provides a native half-precision floating point (__fp16 aka.
float16_t). This patch introduces

* __fp16 as underlying type of Eigen::half if this type is available
* the packet types Packet4hf and Packet8hf representing float16x4_t and
  float16x8_t respectively
* packet-math for the above packets with corresponding scalar type Eigen::half

The packet-math functionality has been implemented by Ashutosh Sharma
<ashutosh.sharma@amperecomputing.com>.

This closes #1940.
This commit is contained in:
David Tellenbach
2020-10-28 20:15:09 +00:00
parent a725a3233c
commit e265f7ed8e
9 changed files with 869 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
test/half_float.cpp
View File

@@ -22,6 +22,9 @@ void test_conversion()
{
using Eigen::half_impl::__half_raw;
// We don't use a uint16_t raw member x if the platform has native Arm __fp16
// support
#if !defined(EIGEN_HAS_ARM64_FP16_SCALAR_ARITHMETIC)
// Conversion from float.
VERIFY_IS_EQUAL(half(1.0f).x, 0x3c00);
VERIFY_IS_EQUAL(half(0.5f).x, 0x3800);
@@ -53,6 +56,41 @@ void test_conversion()
// Conversion from bool.
VERIFY_IS_EQUAL(half(false).x, 0x0000);
VERIFY_IS_EQUAL(half(true).x, 0x3c00);
#endif
#if defined(EIGEN_HAS_ARM64_FP16_SCALAR_ARITHMETIC)
// Conversion from float.
VERIFY_IS_EQUAL(half(1.0f).x, __fp16(1.0f));
VERIFY_IS_EQUAL(half(0.5f).x, __fp16(0.5f));
VERIFY_IS_EQUAL(half(0.33333f).x, __fp16(0.33333f));
VERIFY_IS_EQUAL(half(0.0f).x, __fp16(0.0f));
VERIFY_IS_EQUAL(half(-0.0f).x, __fp16(-0.0f));
VERIFY_IS_EQUAL(half(65504.0f).x, __fp16(65504.0f));
VERIFY_IS_EQUAL(half(65536.0f).x, __fp16(65536.0f)); // Becomes infinity.
// Denormals.
VERIFY_IS_EQUAL(half(-5.96046e-08f).x, __fp16(-5.96046e-08f));
VERIFY_IS_EQUAL(half(5.96046e-08f).x, __fp16(5.96046e-08f));
VERIFY_IS_EQUAL(half(1.19209e-07f).x, __fp16(1.19209e-07f));
// Verify round-to-nearest-even behavior.
float val1 = float(half(__half_raw(0x3c00)));
float val2 = float(half(__half_raw(0x3c01)));
float val3 = float(half(__half_raw(0x3c02)));
VERIFY_IS_EQUAL(half(0.5f * (val1 + val2)).x, __fp16(0.5f * (val1 + val2)));
VERIFY_IS_EQUAL(half(0.5f * (val2 + val3)).x, __fp16(0.5f * (val2 + val3)));
// Conversion from int.
VERIFY_IS_EQUAL(half(-1).x, __fp16(-1));
VERIFY_IS_EQUAL(half(0).x, __fp16(0));
VERIFY_IS_EQUAL(half(1).x, __fp16(1));
VERIFY_IS_EQUAL(half(2).x, __fp16(2));
VERIFY_IS_EQUAL(half(3).x, __fp16(3));
// Conversion from bool.
VERIFY_IS_EQUAL(half(false).x, __fp16(false));
VERIFY_IS_EQUAL(half(true).x, __fp16(true));
#endif
// Conversion to float.
VERIFY_IS_EQUAL(float(half(__half_raw(0x0000))), 0.0f);
@@ -92,6 +130,15 @@ void test_conversion()
VERIFY((numext::isinf)(half(1.0 / 0.0)));
VERIFY((numext::isinf)(half(-1.0 / 0.0)));
#endif
// Conversion to bool
VERIFY(!static_cast<bool>(half(0.0)));
VERIFY(!static_cast<bool>(half(-0.0)));
VERIFY(static_cast<bool>(half(__half_raw(0x7bff))));
VERIFY(static_cast<bool>(half(-0.33333)));
VERIFY(static_cast<bool>(half(1.0)));
VERIFY(static_cast<bool>(half(-1.0)));
VERIFY(static_cast<bool>(half(-5.96046e-08f)));
}
void test_numtraits()
@@ -108,8 +155,12 @@ void test_numtraits()
VERIFY(NumTraits<half>::IsSigned);
VERIFY_IS_EQUAL( std::numeric_limits<half>::infinity().x, half(std::numeric_limits<float>::infinity()).x );
// If we have a native fp16 types this becomes a nan == nan comparision so we have to disable it
#if !defined(EIGEN_HAS_ARM64_FP16_SCALAR_ARITHMETIC)
VERIFY_IS_EQUAL( std::numeric_limits<half>::quiet_NaN().x, half(std::numeric_limits<float>::quiet_NaN()).x );
VERIFY_IS_EQUAL( std::numeric_limits<half>::signaling_NaN().x, half(std::numeric_limits<float>::signaling_NaN()).x );
#endif
VERIFY( (std::numeric_limits<half>::min)() > half(0.f) );
VERIFY( (std::numeric_limits<half>::denorm_min)() > half(0.f) );
VERIFY( (std::numeric_limits<half>::min)()/half(2) > half(0.f) );
@@ -218,8 +269,8 @@ void test_trigonometric_functions()
VERIFY_IS_APPROX(numext::cos(half(0.0f)), half(cosf(0.0f)));
VERIFY_IS_APPROX(cos(half(0.0f)), half(cosf(0.0f)));
VERIFY_IS_APPROX(numext::cos(half(EIGEN_PI)), half(cosf(EIGEN_PI)));
//VERIFY_IS_APPROX(numext::cos(half(EIGEN_PI/2)), half(cosf(EIGEN_PI/2)));
//VERIFY_IS_APPROX(numext::cos(half(3*EIGEN_PI/2)), half(cosf(3*EIGEN_PI/2)));
// VERIFY_IS_APPROX(numext::cos(half(EIGEN_PI/2)), half(cosf(EIGEN_PI/2)));
// VERIFY_IS_APPROX(numext::cos(half(3*EIGEN_PI/2)), half(cosf(3*EIGEN_PI/2)));
VERIFY_IS_APPROX(numext::cos(half(3.5f)), half(cosf(3.5f)));
VERIFY_IS_APPROX(numext::sin(half(0.0f)), half(sinf(0.0f)));