GAMMAINV
- GAMMAINV(probability, alpha, beta)[source]
Calculates the inverse of the gamma cumulative distribution.
GAMMAINV returns the value x such that the gamma CDF evaluated at x equals the given probability, for the specified shape and scale parameters.
- Parameters:
probability (
Operand|int|float) –The probability value(s) for which to find the inverse (must be between 0 and 1).
Supported types:
INTEGER
DECIMAL
INTEGER_ARRAY
DECIMAL_ARRAY
alpha (
Operand|int|float) –The shape parameter α of the distribution (must be > 0).
Supported types:
INTEGER
DECIMAL
INTEGER_ARRAY
DECIMAL_ARRAY
beta (
Operand|int|float) –The scale parameter β of the distribution (must be > 0).
Supported types:
INTEGER
DECIMAL
INTEGER_ARRAY
DECIMAL_ARRAY
- Return type:
- Returns:
A formula object evaluating to the inverse gamma distribution value(s).
Returns DECIMAL if all inputs are scalar
Returns DECIMAL_ARRAY if any input is an array
Supported types:
DECIMAL
DECIMAL_ARRAY
- Raises:
ValueError – If probability, alpha, or beta are not numeric types
Examples
Scalar inverse:
GAMMAINV(0.9, 3.0, 1.0) # Returns the 90th percentile of a gamma distribution with shape=3, scale=1
Array inputs:
GAMMAINV(my_table["probability"], 3.0, 1.0) # Returns an array of inverse gamma values for each row