/*
* Returns the signum function of the argument. If the argument is less than
* zero, it returns -1.0. If the argument is greater than zero, 1.0 is
* returned. If the argument is either positive or negative zero, the
* argument is returned as result.
* <p>
* Special cases:
* <ul>
* <li>{@code signum(+0.0) = +0.0}</li>
* <li>{@code signum(-0.0) = -0.0}</li>
* <li>{@code signum(+infinity) = +1.0}</li>
* <li>{@code signum(-infinity) = -1.0}</li>
* <li>{@code signum(NaN) = NaN}</li>
* </ul>
*
* @param f
* the value whose signum has to be computed.
* @return the value of the signum function.
*/
public static float signum(float f)
{
if (Float.isNaN(f))
{
return(Float.NaN);
}
float sig = f;
if (f > 0)
{
sig = 1.0f;
}
else if (f < 0)
{
sig = -1.0f;
}
return(sig);
}
/*
* Returns the argument's ulp (unit in the last place). The size of a ulp of
* a float value is the positive distance between this value and the float
* value next larger in magnitude. For non-NaN {@code x},
* {@code ulp(-x) == ulp(x)}.
* <p>
* Special cases:
* <ul>
* <li>{@code ulp(+0.0) = Float.MIN_VALUE}</li>
* <li>{@code ulp(-0.0) = Float.MIN_VALUE}</li>
* <li>{@code ulp(+infintiy) = infinity}</li>
* <li>{@code ulp(-infintiy) = infinity}</li>
* <li>{@code ulp(NaN) = NaN}</li>
* </ul>
*
* @param f
* the floating-point value to compute ulp of.
* @return the size of a ulp of the argument.
*/
public static float ulp(float f)
{
// special cases
if (Float.isNaN(f))
{
return(Float.NaN);
}
else if (float.IsInfinity(f))
{
return(Float.POSITIVE_INFINITY);
}
else if (f == Float.MAX_VALUE || f == -Float.MAX_VALUE)
{
return((float)pow(2, 104));
}
f = Math.abs(f);
return(nextafterf(f, Float.MAX_VALUE) - f);
}
/*
* Answers the next larger float value to d.
*
* @param f
* the float value to start
* @return the next larger float value of d.
*
* @since 1.6
*/
public static float nextUp(float f)
{
if (Float.isNaN(f))
{
return(Float.NaN);
}
if ((f == Float.POSITIVE_INFINITY))
{
return(Float.POSITIVE_INFINITY);
}
if (0 == f)
{
return(Float.MIN_VALUE);
}
else if (0 < f)
{
return(Float.intBitsToFloat(Float.floatToIntBits(f) + 1));
}
else
{
return(Float.intBitsToFloat(Float.floatToIntBits(f) - 1));
}
}
