Specifying Initial Balance, Deposits and Withdrawals for a Fund Element

The "Fund Definition" portion of the Fund dialog is used to specify the Initial Balance, Deposits and Withdrawals:

Deposits and withdrawals can be specified as continuous rates and/or as discrete changes.

The Deposit Rate and Withdrawal Rate fields accept constants or links (with dimensions of currency per unit time). These are treated as continuous rates. Hence it would be most appropriate to use these fields only if you had deposits and/or withdrawals that could be approximated as being continuous (e.g., a daily withdrawal). Deposit Rate and Withdrawal Rate must be non-negative.

The Deposits and Withdrawals fields accept discrete change signals. These fields are used to simulate transactions that must be treated in a discrete (as opposed to continuous) manner. The discrete change signals must have dimensions of currency. Discrete change signals can be positive or negative. A negative Deposit is treated as a Withdrawal, and a negative Withdrawal is treated as a Deposit.

Withdrawals only accept discrete change signals with Add instructions. Deposits accept discrete change signals with Add instructions or Replace instructions. When a Fund element receives a Discrete Change with a Replace instruction, the Fund value is reset to the Value specified by the Discrete Change.

The buttons to the right of the Deposits and Withdrawal fields are used to enter multiple discrete changes. These buttons provide access to the following dialog:

Note that you can also enter multiple discrete change signals into this field by separating them by semi-colons:

Note: If a Fund is inside an inactive conditional Container, all discrete and continuous deposits and withdrawals are ignored. If the deposits or withdrawals originate from an active Container, an warning message is written to the run log.

The Permit negative fund balances checkbox controls whether or not the Fund is allowed to have a negative balance. By default, this checkbox is checked on (negative balances are allowed). If negative fund balance are not allowed (the checkbox is cleared), GoldSim automatically adds two additional outputs to the element to account for situations in which you attempt to withdrawal more money than is available.

Note: If negative balances are not allowed, GoldSim checks for a negative balance when discrete withdrawals are requested and, if there is a specified withdrawal rate, during every timestep. If a zero balance is encountered partway through a timestep (and interest is continuous), interest is calculated exactly up to the point until the Fund goes to zero.