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Input_Output_Manager Class Reference

This class is responsible for the input, output and recode operations. More...

#include <Input_Output_Manager.hpp>

List of all members.

Public Member Functions

 Input_Output_Manager (ifstream &basket_file, const char *output_file_name)
int read_in_a_line (set< itemtype > &basket)
 Reads in one transaction from the basketfile.
countertype find_frequent_items (const double min_supp, vector< countertype > &support_of_items)
 Determines the frequent items, fills in the new_code an new_code_inverse vectors.
void basket_recode (const set< itemtype > &original_basket, vector< itemtype > &new_basket)
 Creates an other basket that contains only the frequent items recoded.
void write_out_basket (const set< itemtype > &itemset)
 Writes out an itemset to the output file.
void write_out_basket_and_counter (const set< itemtype > &itemset, const countertype counter)
 Writes out an itemset and its counter to the output file.
void rewind ()
 ~Input_Output_Manager ()

Private Attributes

ifstream & basket_file
 The file that contain the transactions (i.e baskets).
vector< itemtype > new_code
 The new codes of the frequent items.
vector< itemtype > new_code_inverse
 The inverse of new_code vector.

Detailed Description

This class is responsible for the input, output and recode operations.

In frequent itemset mining (FIM) algorithms only frequent items are of interest. Hence it is useful to represent frequent items with integers: 1, 2, ..., n, where n is the number of frequent items. In the original transactional database, the items are also represented with integers, so we have to assign new integers to the frequent items.

Definition at line 34 of file Input_Output_Manager.hpp.

Constructor & Destructor Documentation

Input_Output_Manager::Input_Output_Manager (  ifstream &  basket_file,
const char *  output_file_name
) 
 

Author:
Ferenc Bodon

Definition at line 17 of file Input_Output_Manager.cpp.

Input_Output_Manager::~Input_Output_Manager (   ) 
 

Definition at line 158 of file Input_Output_Manager.cpp.

Member Function Documentation

void Input_Output_Manager::basket_recode (  const set< itemtype > &  original_basket,
vector< itemtype > &  new_basket
) 
 

Creates an other basket that contains only the frequent items recoded.

Parameters:
original_basket The basket to filter and recode.
new_basket The created reduced basket

Definition at line 118 of file Input_Output_Manager.cpp.

References new_code.

Referenced by Apriori::support().

countertype Input_Output_Manager::find_frequent_items (  const double  min_supp,
vector< countertype > &  support_of_items
) 
 

Determines the frequent items, fills in the new_code an new_code_inverse vectors.

Parameters:
min_supp The (relative) support threshold.
support_of_items The support of the items. The ith least frequent item's support is given by support_of_items[i].
Returns:
The number of transactions that the basketfile contains.

Determining the support of the items

Finding the frequent items

Definition at line 59 of file Input_Output_Manager.cpp.

References countertype, new_code, new_code_inverse, and read_in_a_line().

int Input_Output_Manager::read_in_a_line (  set< itemtype > &  basket  ) 
 

Reads in one transaction from the basketfile.

Parameters:
basket The basket that will be filled with the next row of the file.
Returns:
0 if the end of file is reached, otherwise 1;

Definition at line 27 of file Input_Output_Manager.cpp.

References basket_file, and itemtype.

Referenced by find_frequent_items(), and Apriori::support().

void Input_Output_Manager::rewind (   ) 
 

Definition at line 152 of file Input_Output_Manager.cpp.

References basket_file.

void Input_Output_Manager::write_out_basket (  const set< itemtype > &  itemset  ) 
 

Writes out an itemset to the output file.

Definition at line 128 of file Input_Output_Manager.cpp.

References new_code_inverse.

void Input_Output_Manager::write_out_basket_and_counter (  const set< itemtype > &  itemset,
const countertype  counter
) 
 

Writes out an itemset and its counter to the output file.

Definition at line 138 of file Input_Output_Manager.cpp.

References new_code_inverse.

Referenced by Apriori_Trie::candidate_generation_assist().

Member Data Documentation

ifstream& Input_Output_Manager::basket_file [private]
 

The file that contain the transactions (i.e baskets).

Definition at line 67 of file Input_Output_Manager.hpp.

Referenced by read_in_a_line(), and rewind().

vector<itemtype> Input_Output_Manager::new_code [private]
 

The new codes of the frequent items.

if new_code[i] is 0, then i is not frequent, otherwise the new code of item i is new_code[i]-1.

Definition at line 74 of file Input_Output_Manager.hpp.

Referenced by basket_recode(), and find_frequent_items().

vector<itemtype> Input_Output_Manager::new_code_inverse [private]
 

The inverse of new_code vector.

new_code_inverse[new_code[i]-1]=i if i is a frequent item.

Definition at line 80 of file Input_Output_Manager.hpp.

Referenced by find_frequent_items(), write_out_basket(), and write_out_basket_and_counter().

The documentation for this class was generated from the following files:
Generated on Fri Mar 11 14:48:06 2005 for APRIORI algorithm by  doxygen 1.3.9.1