value-size.tex

\section{Output Size}
\label{sec:value-size}

Figure \ref{fig:test} gives the formula for calculating the size of a UTxO entry
in the Alonzo era. In addition to the data found in the UTxO in the ShelleyMA
era, the hash of a datum (or $\Nothing$) is added to the output type, which
is accounted for in the size calculation.

\begin{figure*}[h]
  \emph{Constants}
  \begin{align*}
  & \mathsf{JustDataHashSize} \in \MemoryEstimate \\
  & \text{The size of a datum hash wrapped in $\DataHash^?$} \\~
  \\
  & \mathsf{NothingSize} \in \MemoryEstimate \\
  & \text{The size of $\Nothing$ wrapped in $\DataHash^?$}
  \end{align*}
  %
  \emph{Helper Functions}
  \begin{align*}
    & \fun{dataHashSize} \in \DataHash^? \to \MemoryEstimate \\
    & \fun{dataHashSize}~ \Nothing = \mathsf{NothingSize} \\
    & \fun{dataHashSize}~ \wcard = \mathsf{JustDataHashSize} \\
    & \text{Return the size of $\DataHash^?$} \\~\\
    & \fun{utxoEntrySize} \in \TxOut \to \MemoryEstimate \\
    & \fun{utxoEntrySize}~\var{(a, v, d)} = \mathsf{utxoEntrySizeWithoutVal} + (\fun{size} (\fun{getValue}~(a, v, d))) + \mathsf{dataHashSize}~d \\
    & \text{Calculate the size of a UTxO entry}
  \end{align*}
  \caption{Value Size}
  \label{fig:test}
\end{figure*}

\begin{note}
  Get dataHashSize from heapwords on the code
\end{note}

There is a change of constant value from the ShelleyMA era, specifically:

\begin{itemize}
  \item $\mathsf{adaOnlyUTxOSize} = 29$ instead of $27$
  \item $\mathsf{k_0} = 2$ instead of $0$
\end{itemize}

Additionally, the new constants used in Alonzo have values :

\begin{itemize}
  \item $\mathsf{JustDataHashSize} = 10$ words
  \item $\mathsf{NothingSize} = 0$ words
\end{itemize}