Coinselection Functions
=======================

.. c:function:: int wally_coinselect_assets(const uint64_t *values, size_t num_values, uint64_t target, uint64_t attempts, uint32_t io_ratio, uint32_t *indices_out, size_t indices_out_len, size_t *written)

   
   Select input asset values to meet a given payment target.
   
   :param values: The UTXO asset values to select from. Must be ordered from largest to smallest.
   :param num_values: The number of asset values in ``values``.
   :param target: The desired payment value target.
   :param attempts: The maximum number of permutations to check. Must be at least ``num_values`` + 1.
   :param io_ratio: The approximate expected ratio of input to output sizes in the resulting transaction. Larger values will result in more input permutations being searched for exact matches. Must be non-zero, a good default value is ``5``.
   :param indices_out: Destination for the zero-based indices into ``values`` making up the chosen solution. Must be at least the smaller of ``num_values`` and `WALLY_CS_MAX_ASSETS`.
   :param indices_out_len: Size of ``indices_out``. Passing `WALLY_CS_MAX_ASSETS` will ensure the buffer is large enough.
   :param written: Destination for the the number of indices written to ``indices_out``.
   
   This function always finds a solution if one is available. If the given
   values are insufficient to reach the target then zero elements will be
   returned. If the sum of the values returned is not equal to ``target``
   then a change output for the remainder will be required.

   :return: See :ref:`error-codes`


 
Coinselection Constants
-----------------------

.. c:macro:: WALLY_CS_MAX_ASSETS
 
    The maximum number of asset values that can be returned in a coin selection