weibull

survival.weibull(shape, scale)

Weibull survival curve, S(t) = exp(-(t / scale) ** shape).

The accelerated-failure-time parameterization: scale sets the time axis, in the curve’s time unit (typically years), and shape controls whether the hazard rises (shape > 1), falls (shape < 1), or stays constant (shape == 1, equivalent to exponential(1 / scale)).

Parameters

Name	Type	Description	Default
shape	`float`	Weibull shape parameter. Must be positive.	required
scale	`float`	Weibull scale parameter, in the curve’s time unit. Must be positive.	required

Returns

Name	Type	Description
	SurvivalCurve	A `SurvivalCurve` with `survival(t) = exp(-(t / scale) ** shape)`.

Example

from heormodel.survival import weibull curve = weibull(shape=1.2, scale=6.0) round(float(curve.survival(6.0)), 5) 0.36788

# weibull { #heormodel.survival.weibull }

```python
survival.weibull(shape, scale)
```

Weibull survival curve, `S(t) = exp(-(t / scale) ** shape)`.

The accelerated-failure-time parameterization: `scale` sets the time
axis, in the curve's time unit (typically years), and `shape` controls
whether the hazard rises (`shape > 1`), falls (`shape < 1`), or stays
constant (`shape == 1`, equivalent to `exponential(1 / scale)`).

## Parameters {.doc-section .doc-section-parameters}

| Name   | Type             | Description                                                          | Default    |
|--------|------------------|----------------------------------------------------------------------|------------|
| shape  | [float](`float`) | Weibull shape parameter. Must be positive.                           | _required_ |
| scale  | [float](`float`) | Weibull scale parameter, in the curve's time unit. Must be positive. | _required_ |

## Returns {.doc-section .doc-section-returns}

| Name   | Type                                                      | Description                                                        |
|--------|-----------------------------------------------------------|--------------------------------------------------------------------|
|        | [SurvivalCurve](`heormodel.survival.curve.SurvivalCurve`) | A `SurvivalCurve` with `survival(t) = exp(-(t / scale) ** shape)`. |

## Example {.doc-section .doc-section-example}

>>> from heormodel.survival import weibull
>>> curve = weibull(shape=1.2, scale=6.0)
>>> round(float(curve.survival(6.0)), 5)
0.36788