relationalai.std.math.erfinv()

erfinv(number: Number|Producer) -> Expression

Calculates the inverse error function of number, used in probability, statistics, and various calculations involving normal distributions. If number is a Producer, erfinv() filters out any non-numeric values from the producer. Must be called in a rule or query context.

Parameters

Name	Type	Description
number	Producer or Python Number object	The value to calculate the inverse error function of.

Returns

An Expression object.

Example

Use erfinv() to calculate the inverse error function of a number:

import relationalai as rai
from relationalai.std import math


# =====
# SETUP
# =====

model = rai.Model("MyModel")
Measurement = model.Type("Measurement")

with model.rule():
    Measurement.add(id=1).set(value=0.5)
    Measurement.add(id=2).set(value=-0.5)
    Measurement.add(id=3).set(value="INVALID")  # Non-numeric value


# =======
# EXAMPLE
# =======

# Set an erfinv_value property to the inverse error function of each measurement's value.
with model.rule():
    measurement = Measurement()
    measurement.set(erfinv_value=math.erfinv(measurement.value))

# Since erfinv() filters out non-numeric values, the erfinv_value property
# is not set for the measurement with id=3.
with model.query() as select:
    measurement = Measurement()
    response = select(measurement.id, measurement.erfinv_value)

print(response.results)
#    id  erfinv_value
# 0   1      0.476936
# 1   2     -0.476936
# 2   3           NaN

See Also

• erf()