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e - Generate Euler's number

e is a fundamental value in mathematics and physics. It is an irrational number, meaning it can not be represented as a fraction, however for the sake of our memory buffers, we have limited it to 15 decimal places, so the value it produces is 2.718281828459045

Syntax

e(): number

Example - Modelling exponential growth

Logs are not only a source of powerful insight, but also present rich predictive capabilities. Using 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
}