# anc_to_deme_dict { #spaceprime.anc_to_deme_dict }

`anc_to_deme_dict(anc_pops, deme_dict)`

Converts the ancestral population assignments of demes into a dictionary mapping ancestral population IDs to deme indices.

## Parameters

| Name        | Type             | Description                                                                                  | Default    |
|-------------|------------------|----------------------------------------------------------------------------------------------|------------|
| `anc_pops`  | np.ndarray       | An array containing the ancestral population assignments of all demes across the landscape.  | _required_ |
| `deme_dict` | Dict\[int, int\] | A dictionary mapping deme indices to the number of individuals being sampled from each deme. | _required_ |

## Returns

| Type                     | Description                                                                              |
|--------------------------|------------------------------------------------------------------------------------------|
| Dict\[int, List\[int\]\] | A dictionary mapping each ancestral population ID to the range of assigned deme indices. |