SETTINGS

In order to create a PM, we will need to set a particular parameter when creating the asset. This parameter can not be changed after creation of the asset.

Further, A PM-asset should have the following flags (not permissions):

{

   "disable_force_settle" : true,

   "global_settle" : false,

   "witness_fed_asset" : false,

   "committee_fed_asset" : false

}

and these MPA-options:

{

 "feed_lifetime_sec" : 60 * 60 * 24 * 356,

 "minimum_feeds" : 1,

 "force_settlement_delay_sec" : 60

 "force_settlement_offset_percent" : 0

 "maximum_force_settlement_volume" : 100 * GRAPHENE_1_PERCENT,

 "short_backing_asset" : "1.3.0",

}

Note

Unfortunatelly, create_asset cannot create prediction markets. Thus, we need to construct our asser_create_operationmanually (see below).

Note

The precision of the prediction market asset has to be identical with the short backing asset’s precision.

SETTLEMENT AUTHORITIES

The issue can choose between three parties that are allowed to settle the prediction market:

Committee
Witnesses
Other accounts

Committee

If only the committee is supposed to be able to settle the market, you need to set the options to :

{

 "witness_fed_asset" : false,

 "committee_fed_asset" : true

}

Witnesses

If only the witnesses are supposed to be able to settle the market, you need to set the options to :

{

 "witness_fed_asset" : true,

 "committee_fed_asset" : false

}

Note

The idea here is that the median of all price feeds published by the witnesses indicates a positive or negative resolution of the prediction market.

Other Accounts

Similar to Privatized BitAssets, the feed can be also published by a arbitrary set of accounts. It is important to understand that in order to settle a prediction market, only one price feed is requried. Hence, anyone in the list of allowed settlers can settle the market and no consensus needs to be reached. Alternatively, if you want to settle a market only if several accounts can reach a consensus, a new resulution account can be created that uses hierarchical multi-signature similar to the committee-account.The list of settlement price producers can be defined with:

>>> update_asset_feed_producers <symbol> ["account-a", "account-b"] true

PYTHON EXAMPLE

from grapheneapi import GrapheneClient

import json



perm = {}

perm["charge_market_fee"] = 0x01

perm["white_list"] = 0x02

perm["override_authority"] = 0x04

perm["transfer_restricted"] = 0x08

perm["disable_force_settle"] = 0x10

perm["global_settle"] = 0x20

perm["disable_confidential"] = 0x40

perm["witness_fed_asset"] = 0x80

perm["committee_fed_asset"] = 0x100

GRAPHENE_100_PERCENT = 10000

GRAPHENE_1_PERCENT = GRAPHENE_100_PERCENT / 100





class Config():

    wallet_host           = "localhost"

    wallet_port           = 8092

    wallet_user           = ""

    wallet_password       = ""



if __name__ == '__main__':

    graphene = GrapheneClient(Config)



    issuer = "nathan"

    symbol = "PMMP"

    backing = "1.3.0"



    account = graphene.rpc.get_account(issuer)

    asset = graphene.rpc.get_asset(backing)



    permissions = {"charge_market_fee" : True,

                   "white_list" : True,

                   "override_authority" : True,

                   "transfer_restricted" : True,

                   "disable_force_settle" : True,

                   "global_settle" : True,

                   "disable_confidential" : True,

                   "witness_fed_asset" : True,

                   "committee_fed_asset" : True,

                   }

    flags       = {"charge_market_fee" : False,

                   "white_list" : False,

                   "override_authority" : False,

                   "transfer_restricted" : False,

                   "disable_force_settle" : True,

                   "global_settle" : False,

                   "disable_confidential" : False,

                   "witness_fed_asset" : False,

                   "committee_fed_asset" : False,

                   }

    permissions_int = 0

    for p in permissions :

        if permissions[p]:

            permissions_int += perm[p]

    flags_int = 0

    for p in permissions :

        if flags[p]:

            flags_int += perm[p]

    options = {"max_supply" : 10000000000,

               "market_fee_percent" : 0,

               "max_market_fee" : 0,

               "issuer_permissions" : permissions_int,

               "flags" : flags_int,

               "core_exchange_rate" : {

                   "base": {

                       "amount": 10,

                       "asset_id": asset["id"]},

                   "quote": {

                       "amount": 10,

                       "asset_id": "1.3.1"}},

               "whitelist_authorities" : [],

               "blacklist_authorities" : [],

               "whitelist_markets" : [],

               "blacklist_markets" : [],

               "description" : "Prediction Market"

               }

    mpaoptions = {"feed_lifetime_sec" : 60 * 60 * 24 * 14,

                  "minimum_feeds" : 1,

                  "force_settlement_delay_sec" : 10,

                  "force_settlement_offset_percent" : 0 * GRAPHENE_1_PERCENT,

                  "maximum_force_settlement_volume" : 100 * GRAPHENE_1_PERCENT,

                  "short_backing_asset" : asset["id"],

                  }



    op = graphene.rpc.get_prototype_operation("asset_create_operation")

    op[1]["issuer"] = account["id"]

    op[1]["symbol"] = symbol

    op[1]["precision"] = asset["precision"]

    op[1]["common_options"] = options

    op[1]["bitasset_opts"] = mpaoptions



    """ This flag will declare the asset as a prediction market

        asset!

    """

    op[1]["is_prediction_market"] = True



    handle = graphene.rpc.begin_builder_transaction()

    graphene.rpc.add_operation_to_builder_transaction(handle, op)

    graphene.rpc.set_fees_on_builder_transaction(handle, "1.3.0")

    tx = graphene.rpc.sign_builder_transaction(handle, True)

    print(json.dumps(tx, indent=4))

source : http://docs.bitshares.org/bitshares/tutorials/pm-create-manual.html

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