LOG1P

Description

The LOG1P function is used to calculate the value of the expression log(1 + expr). This function is very useful in numerical computations, especially when dealing with values close to zero, as it can avoid numerical instability issues that may arise from directly calculating the log function.

Syntax

LOG1P(expr)

Parameters

• expr: A double type value for which the log(1 + expr) value needs to be calculated.

Return Value

Returns the calculation result, which is of type double.

Example Usage

1. Calculate the value of log1p(0):

   SELECT LOG1P(0);
   

Result: {#result}

结果：

0.0

2. Calculate the log1p value of a series of numbers:

   SELECT LOG1P(0.1), LOG1P(0.01), LOG1P(0.001);
   

Result: {#result}

结果：

0.09531017980432487 0.009950330853168083 9.995003330835331E-4

3. In practical applications, you can use the LOG1P function to calculate the log-odds value in probability models:

   SELECT LOG1P(2) - LOG1P(1) AS log_odds;
   

Result:

 0.4054651081081643

Precautions

• When expr is negative, the LOG1P function will return NULL.
• When using the LOG1P function, ensure that the input value does not cause the result to exceed the range of the double type.