$atanh (aggregation)
$atanh
New in version 4.2.
Returns the inverse hyperbolic tangent (hyperbolic arc tangent) of a value.
$atanh
has the following syntax:{ $atanh: <expression> } $atanh
takes any valid expression that resolves to a number between-1
and1
, e.g.-1 <= value <= 1
.$atanh
returns values in radians. Use$radiansToDegrees
operator to convert the output value from radians to degrees.By default
$atanh
returns values as adouble
.$atanh
can also return values as a 128-bit decimal as long as the<expression>
resolves to a 128-bit decimal value.For more information on expressions, see Expressions.
Behavior
null
, NaN
, and +/- Infinity

If the argument resolves to a value of null
or refers to a field
that is missing, $atanh
returns null
. If the
argument resolves to NaN
, $atanh
returns NaN
.
If the argument resolves to negative or positive infinity,
$atanh
throws an error. If the argument resolves to
+1
or -1
, $atanh
returns Infinity
and
-Infinity
respectively.
Example | Results | |||
---|---|---|---|---|
{ $atanh: NaN } | NaN | |||
{ $atanh: null } | null | |||
{ $atanh: 1 } | Infinity | |||
{ $atanh: -1} | -Infinity | |||
or
| Throws an error message resembling the following formatted output:
|