apostolof-ece-auth-gr
/
authParallelAndDistributedSystemsCourseExercise4
1
0
Fork 0
Code Releases Activity
Browse Source

Delete serial_gs_pagerank_functions.c

master
mtzikara 6 years ago
committed by GitHub
parent
1aaa4028c8
commit
1bb202a3a4
No known key found for this signature in database GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 0 additions and 502 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 502
      serial/serial_gs_pagerank_functions.c

502
serial/serial_gs_pagerank_functions.c
View File

@ -1,502 +0,0 @@
/* ===== INCLUDES ===== */
#include "serial_gs_pagerank_functions.h"
/* ===== CONSTANTS ===== */
const char *ARGUMENT_CONVERGENCE_TOLERANCE = "-c";
const char *ARGUMENT_MAX_ITERATIONS = "-m";
const char *ARGUMENT_DAMPING_FACTOR = "-a";
const char *ARGUMENT_VERBAL_OUTPUT = "-v";
const char *ARGUMENT_OUTPUT_HISTORY = "-h";
const char *ARGUMENT_OUTPUT_FILENAME = "-o";
const int NUMERICAL_BASE = 10;
char *DEFAULT_OUTPUT_FILENAME = "pagerank_output";
const int FILE_READ_BUFFER_SIZE = 4096;
const int CONVERGENCE_CHECK_ITERATION_PERIOD = 2;
const int SPARSITY_INCREASE_ITERATION_PERIOD = 10;
/* ===== FUNCTIONS ===== */
int pagerank(CsrSparseMatrix *transitionMatrix, double **pagerankVector,
bool *convergenceStatus, Parameters parameters) {
// Variables declaration
int iterations = 0, numberOfPages = parameters.numberOfPages;
double delta, *pagerankDifference, *previousPagerankVector,
*convergedPagerankVector, *linksFromConvergedPagesPagerankVector;
CooSparseMatrix linksFromConvergedPages = initCooSparseMatrix();
bool *convergenceMatrix;
// Space allocation
{
size_t sizeofDouble = sizeof(double);
// pagerankDifference used to calculate delta
pagerankDifference = (double *) malloc(numberOfPages * sizeofDouble);
// previousPagerankVector holds last iteration's pagerank vector
previousPagerankVector = (double *) malloc(numberOfPages * sizeofDouble);
// convergedPagerankVector is the pagerank vector of converged pages only
convergedPagerankVector = (double *) malloc(numberOfPages * sizeofDouble);
// linksFromConvergedPagesPagerankVector holds the partial sum of the
// pagerank vector, that describes effect of the links from converged
// pages to non converged pages
linksFromConvergedPagesPagerankVector = (double *) malloc(numberOfPages * sizeofDouble);
// convergenceMatrix indicates which pages have converged
convergenceMatrix = (bool *) malloc(numberOfPages * sizeof(bool));
*convergenceStatus = false;
// Initialization
allocMemoryForCoo(&linksFromConvergedPages, transitionMatrix->numberOfNonZeroElements);
for (int i=0; i<numberOfPages; ++i) {
convergedPagerankVector[i] = 0;
convergenceMatrix[i] = false;
linksFromConvergedPagesPagerankVector[i] = 0;
}
}
if (parameters.verbose) {
printf(ANSI_COLOR_YELLOW "\n----- Starting iterations -----\n" ANSI_COLOR_RESET);
}
do {
// Stores previous pagerank vector
memcpy(previousPagerankVector, *pagerankVector, numberOfPages * sizeof(double));
// Calculates new pagerank vector
calculateNextPagerank(transitionMatrix, previousPagerankVector,
pagerankVector, linksFromConvergedPagesPagerankVector,
convergedPagerankVector, numberOfPages,
parameters.dampingFactor);
if (parameters.history) {
// Outputs pagerank vector to file
savePagerankToFile(parameters.outputFilename, iterations != 0,
*pagerankVector, numberOfPages, iterations);
}
// Periodically checks for convergence
if (!(iterations % CONVERGENCE_CHECK_ITERATION_PERIOD)) {
// Builds pagerank vectors difference
for (int i=0; i<numberOfPages; ++i) {
pagerankDifference[i] = (*pagerankVector)[i] - previousPagerankVector[i];
}
// Calculates convergence
delta = vectorNorm(pagerankDifference, numberOfPages);
if (delta < parameters.convergenceCriterion) {
// Converged
*convergenceStatus = true;
}
}
// Periodically increases sparsity
if (iterations && !(iterations % SPARSITY_INCREASE_ITERATION_PERIOD)) {
bool *newlyConvergedPages = (bool *) malloc(numberOfPages * sizeof(bool));
// Checks each individual page for convergence
for (int i=0; i<numberOfPages; ++i) {
double difference = fabs((*pagerankVector)[i] -
previousPagerankVector[i]) / fabs(previousPagerankVector[i]);
newlyConvergedPages[i] = false;
if (!convergenceMatrix[i] && difference < parameters.convergenceCriterion){
// Page converged
newlyConvergedPages[i] = true;
convergenceMatrix[i] = true;
convergedPagerankVector[i] = (*pagerankVector)[i];
}
}
for (int i=0; i<numberOfPages; ++i) {
// Filters newly converged pages
if (newlyConvergedPages[i] == true) {
// Checks if this converged page has an out-link to a non converged one
int rowStartIndex = transitionMatrix->rowCumulativeIndexes[i],
rowEndIndex = transitionMatrix->rowCumulativeIndexes[i+1];
if (rowEndIndex > rowStartIndex) {
// This row (page) has non zero elements (out-links)
for (int j=rowStartIndex; j<rowEndIndex; ++j) {
// Checks for links from converged pages to non converged
int pageLinksTo = transitionMatrix->columnIndexes[j];
if (convergenceMatrix[pageLinksTo] == false){
// Link exists, adds element to the vector
addElement(&linksFromConvergedPages,
transitionMatrix->values[j], i, pageLinksTo);
}
}
}
// Increases sparsity of the transition matrix by zeroing
// out elements that correspond to converged pages
zeroOutRow(transitionMatrix, i);
zeroOutColumn(transitionMatrix, i);
// Builds the new linksFromConvergedPagesPagerankVector
cooSparseMatrixVectorMultiplication(linksFromConvergedPages,
*pagerankVector, &linksFromConvergedPagesPagerankVector,
numberOfPages);
}
}
free(newlyConvergedPages);
}
++iterations;
// Outputs information about this iteration
if (iterations%2) {
printf(ANSI_COLOR_BLUE "Iteration %d: delta = %f\n" ANSI_COLOR_RESET, iterations, delta);
} else {
printf(ANSI_COLOR_CYAN "Iteration %d: delta = %f\n" ANSI_COLOR_RESET, iterations, delta);
}
} while (!*convergenceStatus && (parameters.maxIterations == 0 ||
iterations < parameters.maxIterations));
if (!parameters.history) {
// Always outputs last pagerank vector to file
savePagerankToFile(parameters.outputFilename, false, *pagerankVector,
numberOfPages, iterations);
}
// Frees memory
free(pagerankDifference);
free(previousPagerankVector);
free(convergedPagerankVector);
free(linksFromConvergedPagesPagerankVector);
free(convergenceMatrix);
destroyCooSparseMatrix(&linksFromConvergedPages);
return iterations;
}
/*
* initialize allocates required memory for arrays, reads the web graph from the
* from the file and creates the initial transition probability distribution
* matrix.
*/
void initialize(CsrSparseMatrix *transitionMatrix,
double **pagerankVector, Parameters *parameters) {
// Reads web graph from file
if ((*parameters).verbose) {
printf(ANSI_COLOR_YELLOW "----- Reading graph from file -----\n" ANSI_COLOR_RESET);
}
generateNormalizedTransitionMatrixFromFile(transitionMatrix, parameters);
// Outputs the algorithm parameters to the console
if ((*parameters).verbose) {
printf(ANSI_COLOR_YELLOW "\n----- Running with parameters -----\n" ANSI_COLOR_RESET\
"Number of pages: %d", (*parameters).numberOfPages);
if (!(*parameters).maxIterations) {
printf("\nMaximum number of iterations: inf");
} else {
printf("\nMaximum number of iterations: %d", (*parameters).maxIterations);
}
printf("\nConvergence criterion: %f" \
"\nDamping factor: %f" \
"\nGraph filename: %s\n", (*parameters).convergenceCriterion,
(*parameters).dampingFactor, (*parameters).graphFilename);
}
// Allocates memory for the pagerank vector
(*pagerankVector) = (double *) malloc((*parameters).numberOfPages * sizeof(double));
double webUniformProbability = 1. / (*parameters).numberOfPages;
for (int i=0; i<(*parameters).numberOfPages; ++i) {
(*pagerankVector)[i] = webUniformProbability;
}
}
// ==================== MATH UTILS ====================
/*
* calculateNextPagerank calculates the product of the multiplication
* between a matrix and the a vector in a cheap way.
*/
void calculateNextPagerank(CsrSparseMatrix *transitionMatrix,
double *previousPagerankVector, double **pagerankVector,
double *linksFromConvergedPagesPagerankVector,
double *convergedPagerankVector, int vectorSize, double dampingFactor) {
// Calculates the web uniform probability once.
double webUniformProbability = 1. / vectorSize;
csrSparseMatrixVectorMultiplication(*transitionMatrix, previousPagerankVector,
pagerankVector, vectorSize);
for (int i=0; i<vectorSize; ++i) {
(*pagerankVector)[i] = dampingFactor * (*pagerankVector)[i];
}
double normDifference = vectorNorm(previousPagerankVector, vectorSize) -
vectorNorm(*pagerankVector, vectorSize);
for (int i=0; i<vectorSize; ++i) {
(*pagerankVector)[i] += normDifference * webUniformProbability +
linksFromConvergedPagesPagerankVector[i] + convergedPagerankVector[i];
}
}
/*
* vectorNorm calculates the first norm of a vector.
*/
double vectorNorm(double *vector, int vectorSize) {
double norm = 0.;
for (int i=0; i<vectorSize; ++i) {
norm += fabs(vector[i]);
}
return norm;
}
// ==================== PROGRAM INPUT AND OUTPUT UTILS ====================
/*
* parseArguments parses the command line arguments given by the user.
*/
void parseArguments(int argumentCount, char **argumentVector, Parameters *parameters) {
if (argumentCount < 2 || argumentCount > 10) {
validUsage(argumentVector[0]);
}
(*parameters).numberOfPages = 0;
(*parameters).maxIterations = 0;
(*parameters).convergenceCriterion = 1;
(*parameters).dampingFactor = 0.85;
(*parameters).verbose = false;
(*parameters).history = false;
(*parameters).outputFilename = DEFAULT_OUTPUT_FILENAME;
char *endPointer;
int argumentIndex = 1;
while (argumentIndex < argumentCount) {
if (!strcmp(argumentVector[argumentIndex], ARGUMENT_CONVERGENCE_TOLERANCE)) {
argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
double convergenceInput = strtod(argumentVector[argumentIndex], &endPointer);
if (convergenceInput == 0) {
printf("Invalid convergence argument\n");
exit(EXIT_FAILURE);
}
(*parameters).convergenceCriterion = convergenceInput;
} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_MAX_ITERATIONS)) {
argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
size_t iterationsInput = strtol(argumentVector[argumentIndex], &endPointer, NUMERICAL_BASE);
if (iterationsInput == 0 && endPointer) {
printf("Invalid iterations argument\n");
exit(EXIT_FAILURE);
}
(*parameters).maxIterations = iterationsInput;
} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_DAMPING_FACTOR)) {
argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
double alphaInput = strtod(argumentVector[argumentIndex], &endPointer);
if ((alphaInput == 0 || alphaInput > 1) && endPointer) {
printf("Invalid alpha argument\n");
exit(EXIT_FAILURE);
}
(*parameters).dampingFactor = alphaInput;
} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_VERBAL_OUTPUT)) {
(*parameters).verbose = true;
} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_OUTPUT_HISTORY)) {
(*parameters).history = true;
} else if (!strcmp(argumentVector[argumentIndex], ARGUMENT_OUTPUT_FILENAME)) {
argumentIndex = checkIncrement(argumentIndex, argumentCount, argumentVector[0]);
if (fopen(argumentVector[argumentIndex], "w") == NULL) {
printf("Invalid output filename. Reverting to default.\n");
continue;
}
(*parameters).outputFilename = argumentVector[argumentIndex];
} else if (argumentIndex == argumentCount - 1) {
(*parameters).graphFilename = argumentVector[argumentIndex];
} else {
validUsage(argumentVector[0]);
exit(EXIT_FAILURE);
}
++argumentIndex;
}
}
/*
* readGraphFromFile loads the file supplied in the command line arguments to an
* array (directedWebGraph) that represents the graph.
*/
void generateNormalizedTransitionMatrixFromFile(CsrSparseMatrix *transitionMatrix,
Parameters *parameters){
FILE *graphFile;
// Opens the file for reading
graphFile = fopen((*parameters).graphFilename, "r+");
if (!graphFile) {
printf("Error opening file \n");
exit(EXIT_FAILURE);
}
char buffer[FILE_READ_BUFFER_SIZE];
char *readResult;
// Skips the first two lines
readResult = fgets(buffer, FILE_READ_BUFFER_SIZE, graphFile);
readResult = fgets(buffer, FILE_READ_BUFFER_SIZE, graphFile);
if (readResult == NULL) {
printf("Error while reading from the file. Does the file have the correct format?\n");
exit(EXIT_FAILURE);
}
// Third line contains the numbers of nodes and edges
int numberOfNodes = 0, numberOfEdges = 0;
readResult = fgets(buffer, FILE_READ_BUFFER_SIZE, graphFile);
if (readResult == NULL) {
printf("Error while reading from the file. Does the file have the correct format?\n");
exit(EXIT_FAILURE);
}
// Parses the number of nodes and number of edges
{
// Splits string to whitespace
char *token = strtok(buffer, " ");
bool nextIsNodes = false, nextIsEdges = false;
while (token != NULL) {
if (strcmp(token, "Nodes:") == 0) {
nextIsNodes = true;
} else if (nextIsNodes) {
numberOfNodes = atoi(token);
nextIsNodes = false;
} else if (strcmp(token, "Edges:") == 0) {
nextIsEdges = true;
} else if (nextIsEdges) {
numberOfEdges = atoi(token);
break;
}
// Gets next string token
token = strtok (NULL, " ,.-");
}
}
if ((*parameters).verbose) {
printf("File claims number of pages is: %d\nThe number of edges is: %d\n",
numberOfNodes, numberOfEdges);
}
// Skips the fourth line
readResult = fgets(buffer, 512, graphFile);
if (readResult == NULL) {
printf("Error while reading from the file. Does the file have the correct format?\n");
exit(EXIT_FAILURE);
}
int maxPageIndex = 0;
CooSparseMatrix tempMatrix = initCooSparseMatrix();
allocMemoryForCoo(&tempMatrix, numberOfEdges);
for (int i=0; i<numberOfEdges; i++) {
int fileFrom = 0, fileTo = 0;
if (!fscanf(graphFile, "%d %d", &fileFrom, &fileTo)) {
break;
}
if (fileFrom > maxPageIndex) {
maxPageIndex = fileFrom;
}
if (fileTo > maxPageIndex) {
maxPageIndex = fileTo;
}
addElement(&tempMatrix, 1, fileFrom, fileTo);
}
if ((*parameters).verbose) {
printf("Max page index found is: %d\n", maxPageIndex);
}
(*parameters).numberOfPages = maxPageIndex + 1;
// Calculates the outdegree of each page and assigns the uniform probability
// of transition to the elements of the corresponding row
int* pageOutdegree = malloc((*parameters).numberOfPages*sizeof(int));
for (int i=0; i<(*parameters).numberOfPages; ++i){
pageOutdegree[i] = 0;
}
for (int i=0; i<numberOfEdges; ++i) {
int currentRow = tempMatrix.elements[i]->rowIndex;
++pageOutdegree[currentRow];
}
for (int i=0; i<tempMatrix.size; ++i) {
tempMatrix.elements[i]->value = 1./pageOutdegree[tempMatrix.elements[i]->rowIndex];
}
free(pageOutdegree);
// Transposes the temporary transition matrix (P^T).
transposeSparseMatrix(&tempMatrix);
allocMemoryForCsr(transitionMatrix, numberOfEdges);
// Transforms the temporary COO matrix to the desired CSR format
transformToCSR(tempMatrix, transitionMatrix);
destroyCooSparseMatrix(&tempMatrix);
fclose(graphFile);
}
/*
* validUsage outputs a message to the console that informs the user of the
* correct (valid) way to use the program.
*/
void validUsage(char *programName) {
printf("%s [-c convergence_criterion] [-m max_iterations] [-a alpha] [-v] [-h] [-o output_filename] <graph_file>" \
"\n-c convergence_criterion" \
"\n\tthe convergence tolerance criterion" \
"\n-m max_iterations" \
"\n\tmaximum number of iterations to perform" \
"\n-a alpha" \
"\n\tthe damping factor" \
"\n-v enable verbal output" \
"\n-h enable history output to file" \
"\n-o output_filename" \
"\n\tfilename and path for the output" \
"\n", programName);
exit(EXIT_FAILURE);
}
/*
* checkIncrement is a helper function for parseArguments function.
*/
int checkIncrement(int previousIndex, int maxIndex, char *programName) {
if (previousIndex == maxIndex) {
validUsage(programName);
exit(EXIT_FAILURE);
}
return ++previousIndex;
}
void savePagerankToFile(char *filename, bool append, double *pagerankVector,
int vectorSize, int iteration) {
FILE *outputFile;
if (append) {
outputFile = fopen(filename, "a");
} else {
outputFile = fopen(filename, "w");
}
if (outputFile == NULL) {
printf("Error while opening the output file.\n");
return;
}
// Saves the pagerank vector
//fprintf(outputFile, "Iteration %d:\t", iteration);
double sum = 0;
for (int i=0; i<vectorSize; ++i) {
sum += pagerankVector[i];
}
//fprintf(outputFile, "%f\n", sum);
for (int i=0; i<vectorSize; ++i) {
fprintf(outputFile, "%d = %.10g\n", i, pagerankVector[i]/sum);
}
fclose(outputFile);
}
Write Preview
Loading…
Cancel
Save