assertThat(ONE_VALUE_STATS.populationVariance()).isWithin(0.0).of(0.0);
    assertThat(Stats.of(POSITIVE_INFINITY).populationVariance()).isNaN();
    assertThat(Stats.of(NEGATIVE_INFINITY).populationVariance()).isNaN();
    assertThat(Stats.of(NaN).populationVariance()).isNaN();
    assertThat(TWO_VALUES_STATS.populationVariance())
        .isWithin(ALLOWED_ERROR)
        .of(TWO_VALUES_SUM_OF_SQUARES_OF_DELTAS / 2);

        assertWithMessage("mean of " + values).that(mean).isNaN();
        assertWithMessage("mean by addAll(Stats) of " + values).that(meanByAddAllStats).isNaN();
      } else if (values.hasAnyPositiveInfinity() && values.hasAnyNegativeInfinity()) {
        assertWithMessage("mean of " + values).that(mean).isNaN();
        assertWithMessage("mean by addAll(Stats) of " + values).that(meanByAddAllStats).isNaN();
      } else if (values.hasAnyPositiveInfinity()) {

//
//	x[i] < x[j] || (math.IsNaN(x[i]) && !math.IsNaN(x[j]))
func (x Float64Slice) Less(i, j int) bool { return x[i] < x[j] || (isNaN(x[i]) && !isNaN(x[j])) }
func (x Float64Slice) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }

// isNaN is a copy of math.IsNaN to avoid a dependency on the math package.
func isNaN(f float64) bool {
	return f != f
}

    assertThat(createSingleStats(Double.POSITIVE_INFINITY, 1.23).populationCovariance()).isNaN();
    assertThat(createSingleStats(Double.NEGATIVE_INFINITY, 1.23).populationCovariance()).isNaN();
    assertThat(createSingleStats(Double.NaN, 1.23).populationCovariance()).isNaN();
    assertThat(TWO_VALUES_PAIRED_STATS.populationCovariance())
        .isWithin(ALLOWED_ERROR)

      if (values.hasAnyNonFinite()) {
        assertWithMessage("population covariance of " + values).that(populationCovariance).isNaN();
        assertWithMessage("population covariance by addAll(PairedStats) of " + values)
            .that(populationCovarianceByAddAllPartitionedPairedStats)
            .isNaN();
      } else {
        assertWithMessage("population covariance of " + values)
            .that(populationCovariance)

  public void testLog2NaNInfinity() {
    assertEquals(Double.POSITIVE_INFINITY, DoubleMath.log2(Double.POSITIVE_INFINITY));
    assertTrue(Double.isNaN(DoubleMath.log2(Double.NEGATIVE_INFINITY)));
    assertTrue(Double.isNaN(DoubleMath.log2(Double.NaN)));
  }

  @GwtIncompatible // StrictMath
  private strictfp double trueLog2(double d) {
    double trueLog2 = StrictMath.log(d) / StrictMath.log(2);
    // increment until it's >= the true value

package com.google.common.math;

import static com.google.common.base.Preconditions.checkState;
import static com.google.common.primitives.Doubles.isFinite;
import static java.lang.Double.NaN;
import static java.lang.Double.isNaN;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.primitives.Doubles;

/**

}

type hostPathTypeChecker interface {
	Exists() bool
	IsFile() bool
	MakeFile() error
	IsDir() bool
	MakeDir() error
	IsBlock() bool
	IsChar() bool
	IsSocket() bool
	GetPath() string
}

type fileTypeChecker struct {
	path string
	hu   hostutil.HostUtils
}

func (ftc *fileTypeChecker) Exists() bool {

    public val KaType.isDouble: Boolean get() = withValidityAssertion { isClassTypeWithClassId(DefaultTypeClassIds.DOUBLE) }
    public val KaType.isChar: Boolean get() = withValidityAssertion { isClassTypeWithClassId(DefaultTypeClassIds.CHAR) }
    public val KaType.isBoolean: Boolean get() = withValidityAssertion { isClassTypeWithClassId(DefaultTypeClassIds.BOOLEAN) }

        // copySign(x, 1.0) is a branch-free version of abs(x), but with different NaN semantics
        || (a == b) // needed to ensure that infinities equal themselves
        || (Double.isNaN(a) && Double.isNaN(b));
  }

  /**
   * Compares {@code a} and {@code b} "fuzzily," with a tolerance for nearly-equal values.
   *