Cosh¶

Overview¶

The Cosh expression computes the hyperbolic cosine of a numeric value. It is a unary mathematical expression that takes a single numeric input and returns the hyperbolic cosine using the standard mathematical formula cosh(x) = (e^x + e^(-x))/2.

Syntax¶

COSH(expr)

cosh(column)

Arguments¶

Argument	Type	Description
child/expr	Expression/Column	The numeric expression for which to compute the hyperbolic cosine

Return Type¶

Returns a DoubleType value representing the hyperbolic cosine of the input.

Supported Data Types¶

All numeric data types (ByteType, ShortType, IntegerType, LongType, FloatType, DoubleType)
DecimalType values are converted to double precision for computation

Algorithm¶

Inherits from UnaryMathExpression which handles type conversion and null propagation
Delegates the actual computation to Scala's math.cosh function
Input values are converted to Double type before computation
The result is returned as a DoubleType value
Null inputs produce null outputs following standard SQL null semantics

Partitioning Behavior¶

This expression preserves partitioning behavior:

Does not require data shuffle as it operates on individual rows
Maintains existing data partitioning since it's a row-level transformation
Can be executed in parallel across partitions without coordination

Edge Cases¶

Null input returns null (standard null propagation)
Very large positive or negative values may result in overflow, returning Double.PositiveInfinity
Zero input returns 1.0 (cosh(0) = 1)
The function always returns positive values (cosh(x) ≥ 1 for all real x)
NaN input returns NaN

Code Generation¶

This expression supports Tungsten code generation through its parent class UnaryMathExpression, which generates optimized bytecode for mathematical operations rather than falling back to interpreted mode.

Examples¶

-- Basic usage
SELECT COSH(0);
-- Returns: 1.0

SELECT COSH(1);
-- Returns: 1.5430806348152437

SELECT COSH(-1);
-- Returns: 1.5430806348152437

-- With table data
SELECT value, COSH(value) as cosh_value 
FROM VALUES (0), (1), (2), (-1) AS t(value);

// DataFrame API usage
import org.apache.spark.sql.functions.cosh

df.select(cosh($"column_name"))
df.withColumn("cosh_result", cosh($"input_column"))

// Example with literal values
spark.range(5).select(cosh($"id")).show()