GAMMADIST

GAMMADIST(x, alpha, beta, cumulative)[source]

Calculates the gamma distribution probability density (PDF) or cumulative distribution (CDF).

GAMMADIST evaluates either the probability density function (PDF) or the cumulative distribution function (CDF) of the gamma distribution for the given input(s).

Parameters:

  • x (Operand | int | float) – The input value(s) at which to evaluate the distribution (must be ≥ 0).

  • alpha (Operand | int | float) – The shape parameter α of the distribution (must be > 0).

  • beta (Operand | int | float) – The scale parameter β of the distribution (must be > 0).

  • cumulative (Operand | bool) –

    Boolean flag to determine calculation type:

    • False / 0: PDF

    • True / 1: CDF

Return type:

Formula

Returns:

A formula object evaluating to the gamma distribution value(s).

  • Returns DECIMAL if all inputs are scalar

  • Returns DECIMAL_ARRAY if any input is an array

Raises:

  • ValueError – If x, alpha, or beta are not numeric types

  • ValueError – If cumulative is not boolean-compatible

Examples

Probability density function (PDF):

GAMMADIST(2.0, 3.0, 1.0, False)
# Returns the PDF at x=2 for a gamma distribution with shape=3, scale=1

Cumulative distribution function (CDF):

GAMMADIST(2.0, 3.0, 1.0, True)
# Returns the CDF at x=2 for a gamma distribution with shape=3, scale=1

Array inputs:

GAMMADIST(my_table["value"], 3.0, 1.0, True)
# Returns an array of CDF values for each row

``x`` — accepted types

  • DECIMAL

  • DECIMAL_ARRAY

  • INTEGER

  • INTEGER_ARRAY

``arg_2`` — accepted types

  • DECIMAL

  • DECIMAL_ARRAY

  • INTEGER

  • INTEGER_ARRAY

``arg_3`` — accepted types

  • DECIMAL

  • DECIMAL_ARRAY

  • INTEGER

  • INTEGER_ARRAY

``cumulative`` — accepted types

  • BOOLEAN

  • BOOLEAN_ARRAY

  • DECIMAL

  • DECIMAL_ARRAY

  • INTEGER

  • INTEGER_ARRAY

Return types

  • DECIMAL

  • DECIMAL_ARRAY