ln - Compute the natural log

ln, otherwise known as natural log or log to base e (euler's constant). This function will compute the natural log of a numerical value.

Syntax

ln(number: number): number

Arguments

Name	Type	Required	Description
number	number	true	The number whose natural log we seek to find

Example - Modelling exponential growth with Euler's number and natural Log

Logs are not only a source of powerful insight, but also present rich predictive capabilities. Using ln and e, we can build exponential models to view of how growth may occur. Consider the following documents:

{
    "initial_value": 500,
    "current_value": 1000,
    "time_since_start_hours": 10
}

We can begin by calculating the growth rate.:

create growth_rate from ((1 / time_since_start_hours) * (ln(current_value / initial_value)))

Now that we have a value indicating the rate at which we are growing, we can then use e() to calculate our predictive values in 10 hours time:

create prediction_in_ten_hours from (initial_value * power(e(), growth_rate * (time_since_start_hours + 10)))

Now, every log document we have is decorated with a predicted value for what is coming next. The full query looks like this:

create growth_rate from ((1 / time_since_start_hours) * (ln(current_value / initial_value)))
| create prediction_in_ten_hours from (initial_value * power(e(), growth_rate * (time_since_start_hours + 10)))

And our resulting document looks like this:

{
    "initial_value": 500,
    "current_value": 1000,
    "time_since_start_hours": 10,
    "growth_rate": 0.0693,
    "prediction_in_ten_hours": 1999.41
}

fromBase

Next log