/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package hivemall.utils.lang;
import static org.junit.Assert.assertEquals;
import java.util.Random;
import org.junit.Test;
public class HalfFloatTest {
@Test
public void testZero() {
exactCheck(0f);
assertEquals((short) 0, HalfFloat.floatToHalfFloat(0f));
}
@Test
public void testIntegers() {
// Integers between 0 and 2048 can be exactly represented
for (int i = 0; i <= 2048; i++) {
exactCheck((float) i);
exactCheck((float) -i);
}
// Integers between 2049 and 4096 round to a multiple of 2 (even number)
for (int i = 2049; i <= 4096; i++) {
nonExactCheck((float) i, 1f);
nonExactCheck((float) -i, 1f);
}
// Integers between 4097 and 8192 round to a multiple of 4
for (int i = 4097; i <= 8192; i++) {
nonExactCheck((float) i, 3f);
nonExactCheck((float) -i, 3f);
}
// Integers between 8193 and 16384 round to a multiple of 8
for (int i = 8193; i <= 16384; i++) {
nonExactCheck((float) i, 7f);
nonExactCheck((float) -i, 7f);
}
// Integers between 16385 and 32768 round to a multiple of 16
for (int i = 16385; i <= 32768; i++) {
nonExactCheck((float) i, 15f);
nonExactCheck((float) -i, 15f);
}
// Integers between 32769 and 65519 round to a multiple of 32
for (int i = 32769; i <= 65519; i++) {
nonExactCheck((float) i, 31f);
nonExactCheck((float) -i, 31f);
}
}
@Test
public void testOverflow() {
// Integers equal to or above 65520 are rounded to "infinity".
//exactCheck(65520, Float.POSITIVE_INFINITY);
//exactCheck(-65520, Float.NEGATIVE_INFINITY);
final Random rand = new Random();
final int range = Integer.MAX_VALUE - 65521;
for (int i = 0; i < 10; i++) {
int r = rand.nextInt(range);
exactCheck(65521 + r, Float.POSITIVE_INFINITY);
exactCheck(-(65521 + r), Float.NEGATIVE_INFINITY);
}
}
@Test
public void testFiniteValues() {
for (int i = 0x0000; i < 0x7c00; i++) {
exactCheck((short) i);
}
for (int i = 0x8001; i < 0xfc00; i++) {
exactCheck((short) i);
}
}
@Test
public void testSpotcheck() {
final float test[] = {1, 5.960464E-8f, 3, 1.788139E-7f, 8, 4.768372E-7f, 16, 9.536743E-7f,
33, 1.966953E-6f, 83, 4.947186E-6f, 167, 9.953976E-6f, 335, 1.996756E-5f, 838,
4.994869E-5f, 1677, 9.995699E-05f, 2701, 0.000199914f, 4120, 0.0004997253f, 5144,
0.0009994507f, 6168, 0.001998901f, 7454, 0.004997253f, 8478, 0.009994507f, 9502,
0.01998901f, 10854, 0.04998779f, 11878, 0.09997559f, 12902, 0.1999512f, 14336,
0.5f, 15360, 1f, 16384, 2f, 17664, 5f, 18688, 10f, 19712, 20f, 21056, 50f, 22080,
100f, 23104, 200f, 24528, 500f, 25552, 1000f, 26576, 2000f, 27874, 5000f, 28898,
10000f, 29922, 20000f, 31258, 49984f, 32769, -5.960464E-08f, 32771, -1.788139E-07f,
32776, -4.768372E-07f, 32784, -9.536743E-07f, 32801, -1.966953E-06f, 32851,
-4.947186E-06f, 32935, -9.953976E-06f, 33103, -1.996756E-05f, 33606,
-4.994869E-05f, 34445, -9.995699E-05f, 35469, -0.000199914f, 36888, -0.0004997253f,
37912, -0.0009994507f, 38936, -0.001998901f, 40222, -0.004997253f, 41246,
-0.009994507f, 42270, -0.01998901f, 43622, -0.04998779f, 44646, -0.09997559f,
45670, -0.1999512f, 47104, -0.5f, 48128, -1f, 49152, -2f, 50432, -5f, 51456, -10f,
52480, -20f, 53824, -50f, 54848, -100f, 55872, -200f, 57296, -500f, 58320, -1000f,
59344, -2000f, 60642, -5000f, 61666, -10000f, 62690, -20000f, 64026, -49984f};
for (int i = 0; i < test.length; i += 2) {
nonExactCheck((short) test[i], test[i + 1]);
}
}
@Test
public void testInfinity() {
exactCheck(Float.POSITIVE_INFINITY);
exactCheck(Float.NEGATIVE_INFINITY);
}
@Test
public void testNaN() {
exactCheck(Float.NaN);
}
private static void exactCheck(final short f16) {
float f = HalfFloat.halfFloatToFloat(f16);
short hf = HalfFloat.floatToHalfFloat(f);
assertEquals(f16, hf);
}
private static void exactCheck(final float f32) {
exactCheck(f32, f32);
}
private static void exactCheck(final float f32, final float expected) {
short hf = HalfFloat.floatToHalfFloat(f32);
float f = HalfFloat.halfFloatToFloat(hf);
assertEquals(expected, f, 0.0);
}
private static void nonExactCheck(final float f32, float delta) {
short hf = HalfFloat.floatToHalfFloat(f32);
float f = HalfFloat.halfFloatToFloat(hf);
assertEquals(f32, f, delta);
}
private static void nonExactCheck(final short f16, final float f32) {
float f = HalfFloat.halfFloatToFloat(f16);
assertEquals("half float: " + f16, f32, f, 1E-6f);
short hf = HalfFloat.floatToHalfFloat(f);
assertEquals(f16, hf, 1E-6f);
}
}