\par
\subsection{{\tt IV} : {\tt int} vector methods}
\label{subsection:Utilities:proto:IV}
\par
%=======================================================================
\begin{enumerate}
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int * IVinit ( int n, int val ) ;
\end{verbatim}
\index{IVinit@{\tt IVinit()}}
This is the allocator and initializer method for {\tt int} vectors.
Storage for an array with size {\tt n} is found and each
entry is filled with {\tt val}.
A pointer to the array is returned.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int * IVinit2 ( int n ) ;
\end{verbatim}
\index{IVinit2@{\tt IVinit2()}}
This is an allocator method for {\tt int} vectors.
Storage for an array with size {\tt n} is found.
A pointer to the array is returned.
Note, on return, there will likely be garbage in the array.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVfree ( int vec[] ) ;
\end{verbatim}
\index{IVfree@{\tt IVfree()}}
This method releases the storage taken by {\tt vec[]}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVfprintf ( FILE *fp, int n, int y[] ) ;
\end{verbatim}
\index{IVfprintf@{\tt IVfprintf()}}
This method prints {\tt n} entries in {\tt y[]} to file {\tt fp}.
The format is new line followed by lines of five {\tt int}'s in
{\tt " \%4d"} format.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVfp80 ( FILE *fp, int n, int y[], int column, int *pierr ) ;
\end{verbatim}
\index{IVfp80@{\tt IVfp80()}}
This method prints {\tt n} entries in {\tt y[]} to file {\tt fp}.
The method splices vectors together or naturally breaks the large
vectors into lines. 
The {\tt column} value is the present location. 
If the printed value of an array entry will not fit within the eighty
columns of the present line, a newline character is written and the
value starts a new line.
The number of the present column in the line is returned.
If {\tt *pierr < 0}, an IO error has occured.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVfscanf ( FILE *fp, int n, int y[] ) ;
\end{verbatim}
\index{IVfscanf@{\tt IVfscanf()}}
This method scans in {\tt int}'s from file {\tt fp} and places them
in the array {\tt y[]}.
It tries to read in {\tt n} {\tt int}'s, and returns the number
that were actually read.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVcompress ( int n1, int x1[], int y1[],
                  int n2, int x2[], int y2[] ) ;
\end{verbatim}
\index{IVcompress@{\tt IVcompress()}}
Given a pair of arrays {\tt x1[n1]} and {\tt y1[n1]},
fill {\tt x2[n2]} and {\tt y2[n2]} with a subset of the
{\tt (x1[j],y1[j]} entries whose distribution is an approximation.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVcopy ( int n, int y[], int x[] ) ;
\end{verbatim}
\index{IVcopy@{\tt IVcopy()}}
This method copies {\tt n} entries from {\tt x[]} to {\tt y[]},
i.e.,
{\tt y[i] = x[i]} for {\tt 0 <= i < n}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVfill ( int n, int y[], int val ) ;
\end{verbatim}
\index{IVfill@{\tt IVfill()}}
This method fills {\tt n} entries in {\tt y[]} with {\tt val}, 
i.e.,
{\tt y[i] = val} for {\tt 0 <= i < n}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVgather ( int n, int y[], int x[], int index[] ) ;
\end{verbatim}
\index{IVgather@{\tt IVgather()}}
{\tt y[i] = x[index[i]]} for {\tt 0 <= i < n}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int * IVinverse ( int n, int y[] ) ;
\end{verbatim}
\index{IVinverse@{\tt IVinverse()}}
This method allocates and returns a vector of size {\tt n}
that it is the inverse of {\tt y[]}, a permutation vector.
The new vector {\tt x[]} has the property that
{\tt x[y[i]] = y[x[i]] = i};
If {\tt y[]} is not truly a permutation vector, an error message
will be printed and the program exits.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVinvPerm ( int n, int y[], int index[] ) ;
\end{verbatim}
\index{IVinvPerm@{\tt IVinvPerm()}}
This method permutes the vector y as follows.
i.e.,
{\tt y[index[i]] := y[i]}.
See {\tt IVperm()} for a similar function.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVlocateViaBinarySearch ( int n, int y[], int target ) ;
\end{verbatim}
\index{IVlocateViaBinarySearch@{\tt IVlocateViaBinarySearch()}}
The {\tt n} entries of {\tt y[]} must be in nondecreasing order.
If {\tt target} is found in {\tt y[]},
this method returns a location where {\tt target} is found.
If {\tt target} is not in {\tt y[]}, {\tt -1} is returned.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVmax ( int n, int y[], int *ploc ) ;
\end{verbatim}
\index{IVmax@{\tt IVmax()}}
This method returns the maximum entry in {\tt y[0:n-1]}
and puts the first location where it was found into the address
{\tt ploc}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVmaxabs ( int n, int y[], int *ploc ) ;
\end{verbatim}
\index{IVmaxabs@{\tt IVmaxabs()}}
This method returns the maximum magnitude of entries in 
{\tt y[0:n-1]} and puts the first location where 
it was found into the address {\tt ploc}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVmin ( int n, int y[], int *ploc ) ;
\end{verbatim}
\index{IVmin@{\tt IVmin()}}
This method returns the minimum entry in {\tt y[0:n-1]}
and puts the first location where it was found into the address
{\tt ploc}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVminabs ( int n, int y[], int *ploc ) ;
\end{verbatim}
\index{IVminabs@{\tt IVminabs()}}
This method returns the minimum magnitude of entries in 
{\tt y[0:n-1]} and puts the first location where 
it was found into the address {\tt ploc}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVperm ( int n, int y[], int index[] ) ;
\end{verbatim}
\index{IVperm@{\tt IVperm()}}
This method permutes the vector y as follows.
i.e.,
{\tt y[i] := y[index[i]]}.
See {\tt IVinvPerm()} for a similar function.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVramp ( int n, int y[], int start, int inc ) ;
\end{verbatim}
\index{IVramp@{\tt IVramp()}}
This method fills {\tt n} entries in {\tt y[]} with 
values 
{\tt start},
{\tt start + inc},
{\tt start + 2*inc},
{\tt start + 3*inc}, etc.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVscatter ( int n, int y[], int index[], int x[] ) ;
\end{verbatim}
\index{IVscatter@{\tt IVscatter()}}
This method scatters {\tt n} entries of {\tt x[]} into {\tt y[]} 
as follows,
{\tt y[index[i]] = x[i]} 
for {\tt 0 <= i < n}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVsum ( int n, int y[] ) ;
\end{verbatim}
\index{IVsum@{\tt IVsum()}}
This method returns the sum of the first {\tt n} entries 
in the vector {\tt x[]},
i.e., return
$\sum_{\tt i = 0}^{\tt n-1} {\tt x[i]}$.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
int IVsumabs ( int n, int y[] ) ;
\end{verbatim}
\index{IVsumabs@{\tt IVsumabs()}}
This method returns the sum of the absolute values of the 
first {\tt n} entries in the vector {\tt x[]},
i.e., return
$\sum_{\tt i = 0}^{\tt n-1} {\tt abs(x[i])}$.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVswap ( int n, int y[], int x[] ) ;
\end{verbatim}
\index{IVswap@{\tt IVswap()}}
This method swaps the {\tt x[]} and {\tt y[]} vectors as follows.
i.e.,
{\tt y[i] := x[i]} and
{\tt x[i] := y[i]} 
for {\tt 0 <= i < n}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVzero ( int n, int y[] ) ;
\end{verbatim}
\index{IVzero@{\tt IVzero()}}
This method zeroes {\tt n} entries in {\tt y[]},
i.e.,
{\tt y[i] = 0} 
for {\tt 0 <= i < n}.
%-----------------------------------------------------------------------
\item
\begin{verbatim}
void IVshuffle ( int n, int y[], int seed ) ;
\end{verbatim}
\index{IVshuffle@{\tt IVshuffle()}}
This method shuffles the first {\tt n} entries in {\tt y[]}.
The value {\tt seed} is the seed to a random number generator,
and one can get repeatable behavior by repeating {\tt seed}.
%-----------------------------------------------------------------------
\end{enumerate}