mix

survival.mix(curves, weights)

Population mixture: weight several curves’ survival functions.

The mixture survival function is the weighted average sum(weight * curve.survival(t)), the population curve for a cohort made up of subgroups that each follow their own curve, for example responders and non-responders to a treatment. The cumulative hazard implied by that survival function has no closed-form inverse in general, so sampling from the result uses heormodel.survival.curve.numeric_inverse_cumulative_hazard.

Parameters

Name	Type	Description	Default
curves	`Sequence`[SurvivalCurve]	At least two component curves.	required
weights	`Sequence`[`float`]	Mixture weight for each curve, non-negative and summing to 1.	required

Returns

Name	Type	Description
	SurvivalCurve	A new `SurvivalCurve` for the mixture.

Example

from heormodel.survival import exponential, mix curve = mix([exponential(rate=0.1), exponential(rate=0.5)], [0.5, 0.5]) round(float(curve.survival(5.0)), 5) 0.34431

# mix { #heormodel.survival.mix }

```python
survival.mix(curves, weights)
```

Population mixture: weight several curves' survival functions.

The mixture survival function is the weighted average
`sum(weight * curve.survival(t))`, the population curve for a cohort made
up of subgroups that each follow their own curve, for example responders
and non-responders to a treatment. The cumulative hazard implied by that
survival function has no closed-form inverse in general, so sampling from
the result uses `heormodel.survival.curve.numeric_inverse_cumulative_hazard`.

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

| Name    | Type                                                                                                | Description                                                   | Default    |
|---------|-----------------------------------------------------------------------------------------------------|---------------------------------------------------------------|------------|
| curves  | [Sequence](`collections.abc.Sequence`)\[[SurvivalCurve](`heormodel.survival.curve.SurvivalCurve`)\] | At least two component curves.                                | _required_ |
| weights | [Sequence](`collections.abc.Sequence`)\[[float](`float`)\]                                          | Mixture weight for each curve, non-negative and summing to 1. | _required_ |

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

| Name   | Type                                                      | Description                            |
|--------|-----------------------------------------------------------|----------------------------------------|
|        | [SurvivalCurve](`heormodel.survival.curve.SurvivalCurve`) | A new `SurvivalCurve` for the mixture. |

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

>>> from heormodel.survival import exponential, mix
>>> curve = mix([exponential(rate=0.1), exponential(rate=0.5)], [0.5, 0.5])
>>> round(float(curve.survival(5.0)), 5)
0.34431