dfact
Computes the double factorial of an expression.
Ordinary parsing preserves dfact as a symbolic function instead of forcing numerical evaluation. Call evaluate() when a numeric value is required; non-negative integers are then computed exactly and supported non-integers use the generalized gamma-based form.
The parser name dfact corresponds to Nerdamer's double-factorial implementation.
Examples
These examples use Nerdamer Notation.
Keep an integer double factorial symbolic until evaluation is requested.
dfact(6)Preserve the odd double factorial during ordinary parsing.
dfact(7)Interfaces
The same operation is available through the interfaces below.
Nerdamer Notation
Use this form inside input passed to nerdamer(...).
dfact(arg1)nerdamer.dfact
Call the operation through the default nerdamer import.
nerdamer.dfact(x: Expression): ExpressionParameters
| Name | Type | Description |
|---|---|---|
x | Expression | The expression to compute the double factorial of. |
Returns
Expression — The double factorial of `x`.