\section{Item\+Mean\+Normalization Class Reference}
\label{classmlpack_1_1cf_1_1ItemMeanNormalization}\index{Item\+Mean\+Normalization@{Item\+Mean\+Normalization}}


This normalization class performs item mean normalization on raw ratings.  


\subsection*{Public Member Functions}
\begin{DoxyCompactItemize}
\item 
\textbf{ Item\+Mean\+Normalization} ()
\item 
double \textbf{ Denormalize} (const size\+\_\+t, const size\+\_\+t item, const double rating) const
\begin{DoxyCompactList}\small\item\em Denormalize computed rating by adding item mean. \end{DoxyCompactList}\item 
void \textbf{ Denormalize} (const arma\+::\+Mat$<$ size\+\_\+t $>$ \&combinations, arma\+::vec \&predictions) const
\begin{DoxyCompactList}\small\item\em Denormalize computed rating by adding item mean. \end{DoxyCompactList}\item 
const arma\+::vec \& \textbf{ Mean} () const
\begin{DoxyCompactList}\small\item\em Return item mean. \end{DoxyCompactList}\item 
void \textbf{ Normalize} (arma\+::mat \&data)
\begin{DoxyCompactList}\small\item\em Normalize the data by subtracting item mean from each of existing ratings. \end{DoxyCompactList}\item 
void \textbf{ Normalize} (arma\+::sp\+\_\+mat \&cleaned\+Data)
\begin{DoxyCompactList}\small\item\em Normalize the data by subtracting item mean from each of existing ratings. \end{DoxyCompactList}\item 
{\footnotesize template$<$typename Archive $>$ }\\void \textbf{ serialize} (Archive \&ar, const unsigned int)
\begin{DoxyCompactList}\small\item\em Serialization. \end{DoxyCompactList}\end{DoxyCompactItemize}


\subsection{Detailed Description}
This normalization class performs item mean normalization on raw ratings. 

An example of how to use \doxyref{Item\+Mean\+Normalization}{p.}{classmlpack_1_1cf_1_1ItemMeanNormalization} in CF is shown below\+:


\begin{DoxyCode}
\textcolor{keyword}{extern} arma::mat data; \textcolor{comment}{// data is a (user, item, rating) table.}
\textcolor{comment}{// Users for whom recommendations are generated.}
\textcolor{keyword}{extern} arma::Col<size\_t> users;
arma::Mat<size\_t> recommendations; \textcolor{comment}{// Resulting recommendations.}

\textcolor{comment}{// Use ItemMeanNormalization as normalization method.}
CFType<NMFPolicy, ItemMeanNormalization> cf(data);

\textcolor{comment}{// Generate 10 recommendations for all users.}
cf.GetRecommendations(10, recommendations);
\end{DoxyCode}
 

Definition at line 39 of file item\+\_\+mean\+\_\+normalization.\+hpp.



\subsection{Constructor \& Destructor Documentation}
\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_ae784a8a1a7acbab5b02b2a86f410dc82}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!Item\+Mean\+Normalization@{Item\+Mean\+Normalization}}
\index{Item\+Mean\+Normalization@{Item\+Mean\+Normalization}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{Item\+Mean\+Normalization()}
{\footnotesize\ttfamily \textbf{ Item\+Mean\+Normalization} (\begin{DoxyParamCaption}{ }\end{DoxyParamCaption})\hspace{0.3cm}{\ttfamily [inline]}}



Definition at line 43 of file item\+\_\+mean\+\_\+normalization.\+hpp.



\subsection{Member Function Documentation}
\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_a25d019f07e5f97119b7a802306fa747f}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!Denormalize@{Denormalize}}
\index{Denormalize@{Denormalize}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{Denormalize()\hspace{0.1cm}{\footnotesize\ttfamily [1/2]}}
{\footnotesize\ttfamily double Denormalize (\begin{DoxyParamCaption}\item[{const size\+\_\+t}]{,  }\item[{const size\+\_\+t}]{item,  }\item[{const double}]{rating }\end{DoxyParamCaption}) const\hspace{0.3cm}{\ttfamily [inline]}}



Denormalize computed rating by adding item mean. 


\begin{DoxyParams}{Parameters}
{\em $\ast$} & (user) User ID. \\
\hline
{\em item} & Item ID. \\
\hline
{\em rating} & Computed rating before denormalization. \\
\hline
\end{DoxyParams}


Definition at line 130 of file item\+\_\+mean\+\_\+normalization.\+hpp.

\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_a93926452083f79197edc30f83476a40d}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!Denormalize@{Denormalize}}
\index{Denormalize@{Denormalize}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{Denormalize()\hspace{0.1cm}{\footnotesize\ttfamily [2/2]}}
{\footnotesize\ttfamily void Denormalize (\begin{DoxyParamCaption}\item[{const arma\+::\+Mat$<$ size\+\_\+t $>$ \&}]{combinations,  }\item[{arma\+::vec \&}]{predictions }\end{DoxyParamCaption}) const\hspace{0.3cm}{\ttfamily [inline]}}



Denormalize computed rating by adding item mean. 


\begin{DoxyParams}{Parameters}
{\em combinations} & User/\+Item combinations. \\
\hline
{\em predictions} & Predicted ratings for each user/item combination. \\
\hline
\end{DoxyParams}


Definition at line 143 of file item\+\_\+mean\+\_\+normalization.\+hpp.

\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_a6db5f5d76cbd055347cecd9ca90eea86}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!Mean@{Mean}}
\index{Mean@{Mean}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{Mean()}
{\footnotesize\ttfamily const arma\+::vec\& Mean (\begin{DoxyParamCaption}{ }\end{DoxyParamCaption}) const\hspace{0.3cm}{\ttfamily [inline]}}



Return item mean. 



Definition at line 156 of file item\+\_\+mean\+\_\+normalization.\+hpp.

\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_a87410cc06d847eef46d0dfdb137c6be7}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!Normalize@{Normalize}}
\index{Normalize@{Normalize}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{Normalize()\hspace{0.1cm}{\footnotesize\ttfamily [1/2]}}
{\footnotesize\ttfamily void Normalize (\begin{DoxyParamCaption}\item[{arma\+::mat \&}]{data }\end{DoxyParamCaption})\hspace{0.3cm}{\ttfamily [inline]}}



Normalize the data by subtracting item mean from each of existing ratings. 


\begin{DoxyParams}{Parameters}
{\em data} & Input dataset in the form of coordinate list. \\
\hline
\end{DoxyParams}


Definition at line 50 of file item\+\_\+mean\+\_\+normalization.\+hpp.

\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_a9656a2fd4841da15cf4b13ab57aa8000}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!Normalize@{Normalize}}
\index{Normalize@{Normalize}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{Normalize()\hspace{0.1cm}{\footnotesize\ttfamily [2/2]}}
{\footnotesize\ttfamily void Normalize (\begin{DoxyParamCaption}\item[{arma\+::sp\+\_\+mat \&}]{cleaned\+Data }\end{DoxyParamCaption})\hspace{0.3cm}{\ttfamily [inline]}}



Normalize the data by subtracting item mean from each of existing ratings. 


\begin{DoxyParams}{Parameters}
{\em cleaned\+Data} & Input data as a sparse matrix. \\
\hline
\end{DoxyParams}


Definition at line 90 of file item\+\_\+mean\+\_\+normalization.\+hpp.

\mbox{\label{classmlpack_1_1cf_1_1ItemMeanNormalization_af0dd9205158ccf7bcfcd8ff81f79c927}} 
\index{mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}!serialize@{serialize}}
\index{serialize@{serialize}!mlpack\+::cf\+::\+Item\+Mean\+Normalization@{mlpack\+::cf\+::\+Item\+Mean\+Normalization}}
\subsubsection{serialize()}
{\footnotesize\ttfamily void serialize (\begin{DoxyParamCaption}\item[{Archive \&}]{ar,  }\item[{const unsigned}]{int }\end{DoxyParamCaption})\hspace{0.3cm}{\ttfamily [inline]}}



Serialization. 



Definition at line 162 of file item\+\_\+mean\+\_\+normalization.\+hpp.



The documentation for this class was generated from the following file\+:\begin{DoxyCompactItemize}
\item 
/var/www/mlpack.\+ratml.\+org/mlpack.\+org/\+\_\+src/mlpack-\/3.\+3.\+2/src/mlpack/methods/cf/normalization/\textbf{ item\+\_\+mean\+\_\+normalization.\+hpp}\end{DoxyCompactItemize}