MPI: max time

.gitignore

@@ -1 +1,2 @@
 build
+.vimspector.json

src/main.c

@@ -1,12 +1,37 @@
-/*
-  "Hello World" MPI Test Program
-*/
-#include <assert.h>
-#include <stdio.h>
-#include <string.h>
-#include <mpi.h>
+#define _XOPEN_SOURCE 700
+#include <sys/types.h>
 
-int main(int argc, char** argv) {
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+enum HEADER {
+	TRIP_ID = 0,
+	ARRIVAL_TIME,
+	DEPARTURE_TIME,
+	STOP_ID,
+	STOP_SEQUENCE,
+	STOP_HEADSIGN,
+	PICKUP_TYPE,
+	DROP_OFF_TYPE,
+	SHAPE_DIST_TRAVELED,
+	TIMEPOINT,
+	END
+};
+
+#define DELIM ','
+#define OVERLAP 100
+#define STOP_FILE "./stop_times.txt"
+
+int		do_map(char *, size_t);
+void	do_reduce(size_t);
+int		parprocess(MPI_File *, const int, const int);
+
+int
+main(int argc, char **argv)
+{
 	// Initialize the MPI environment
 	MPI_Init(NULL, NULL);
 
@@ -14,6 +39,8 @@ int main(int argc, char** argv) {
 	MPI_Comm_size(MPI_COMM_WORLD, &world_size);
 	MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
 
+	int localmax = 0, globalmax = 0;
+
 	// Get the name of the processor
 	char processor_name[MPI_MAX_PROCESSOR_NAME];
 	int name_len;
@@ -23,37 +50,224 @@ int main(int argc, char** argv) {
 	printf("Hello world from processor %s, rank %d out of %d processors\n",
 	    processor_name, world_rank, world_size);
 
+	int number, size;
+	ssize_t err;
+	MPI_File in;
 
-
-  // We are assuming at least 2 processes for this task
-  if (world_size < 2) {
-    fprintf(stderr, "World size must be greater than 1 for %s\n", argv[0]);
-    MPI_Abort(MPI_COMM_WORLD, 1);
+	if ((err = MPI_File_open(MPI_COMM_WORLD, STOP_FILE, MPI_MODE_RDONLY,
+		 MPI_INFO_NULL, &in))) {
+		fprintf(stderr, "%s: Couldn't open file %s\n", argv[0],
+		    STOP_FILE);
+		exit(-1);
 	}
-  int number;
-  if (world_rank == 0) {
-    // If we are rank 0, set the number to -1 and send it to process 1
-    number = -1;
-    MPI_Send(
-      /* data         = */ &number, 
-      /* count        = */ 1, 
-      /* datatype     = */ MPI_INT, 
-      /* destination  = */ 1, 
-      /* tag          = */ 0, 
-      /* communicator = */ MPI_COMM_WORLD);
-  } else if (world_rank == 1) {
-    MPI_Recv(
-      /* data         = */ &number, 
-      /* count        = */ 1, 
-      /* datatype     = */ MPI_INT, 
-      /* source       = */ 0, 
-      /* tag          = */ 0, 
-      /* communicator = */ MPI_COMM_WORLD, 
-      /* status       = */ MPI_STATUS_IGNORE);
-    printf("Process 1 received number %d from process 0\n", number);
+	MPI_Comm_size(MPI_COMM_WORLD, &size);
+
+	localmax = parprocess(&in, world_rank, world_size);
+
+	MPI_Reduce(&localmax, &globalmax, 1, MPI_INT, MPI_MAX, 0,
+	    MPI_COMM_WORLD);
+	if (world_rank == 0)
+		printf("globalmax: %d\n", globalmax);
+
+	MPI_File_close(&in);
+	MPI_Finalize();
+	exit(0);
 }
 
-    // Finalize the MPI environment.
+time_t
+substr_time(struct tm a, struct tm b)
+{
+	return (a.tm_hour * 3600 + a.tm_min * 60 + a.tm_sec) -
+		(b.tm_hour * 3600 + b.tm_min * 60 + b.tm_sec);
+}
+
+char *
+get_word(char *lines, size_t x, size_t y, size_t num_attr, size_t max_attr)
+{
+	size_t offset = (x * (num_attr * max_attr) + y * (max_attr));
+	return lines + offset;
+}
+
+void
+fill_lines(char *chunk, size_t num_char, size_t num_lines, size_t num_attr,
+	size_t max_attr, char *lines)
+{
+	size_t attr_pos = 0, line_pos = 0, word_pos = 0;
+	for (size_t k = 0; k < num_char; ++k) {
+		if (chunk[k] == DELIM) {
+			// go to next attrib
+			char *word = get_word(lines, line_pos, attr_pos,
+				num_attr, max_attr);
+			memcpy(word, chunk + k - word_pos, word_pos);
+			word[word_pos] = '\0';
+			++attr_pos;
+			word_pos = 0;
+		}
+		else if (chunk[k] == '\n') {
+			++line_pos;
+			attr_pos = 0;
+			word_pos = 0;
+		}
+		else if (chunk[k] == '\r') {}
+		else {
+			++word_pos;
+		}
+	}
+}
+
+void
+get_lines_info(char *chunk, size_t num_char, size_t *max_attr_size,
+	size_t *num_lines)
+{
+	// count max line size and number of lines
+	size_t current_attr_size = 0;
+	for (int k = 0; k < num_char; ++k) {
+		// LINE
+		if (chunk[k] == '\n' || chunk[k] == '\r')
+			++(*num_lines);
+		// ATTRIBUTES
+		if (chunk[k] == DELIM) {
+			if (current_attr_size > *max_attr_size)
+				*max_attr_size = current_attr_size;
+			current_attr_size = 0;
+		} else
+			++current_attr_size;
+	}
+}
+
+// get num of cols of csv
+size_t
+get_num_attr(char *chunk)
+{
+	size_t num_attr = 0;
+	for (size_t k = 0 ; chunk[k] != '\n' ; ++k)
+		if (chunk[k] == DELIM)
+			++num_attr;
+	return num_attr;
+}
+
+int
+do_map(char *chunk, size_t num_char)
+{
+	size_t num_lines = 0, num_attr = 0;
+	size_t max_attr_size = 0;
+
+	get_lines_info(chunk, num_char, &max_attr_size, &num_lines);
+	num_attr = get_num_attr(chunk);
+
+	// allocate lines (just a big continuous chunk)
+	// is a 2d arr of char*
+	char *lines;
+	lines = calloc(1, num_lines * num_attr * max_attr_size);
+
+
+	fill_lines(chunk, num_char, num_lines, num_attr, max_attr_size, lines);
+
+	struct tm dep_time, arr_time;
+	time_t max_time = 0;
+	for (size_t k = 0; k < num_lines; ++k) {
+		memcpy(&dep_time,
+			get_word(lines, k, DEPARTURE_TIME, num_attr,
+				max_attr_size),
+			sizeof(struct tm));
+		memcpy(&arr_time,
+			get_word(lines, k, ARRIVAL_TIME, num_attr,
+				max_attr_size),
+			sizeof(struct tm));
+		// arr_time.tm_sec);
+
+		strptime(get_word(lines, k, DEPARTURE_TIME, num_attr,
+				 max_attr_size),
+			"%H:%M:%S", &dep_time);
+
+		strptime(get_word(lines, k, ARRIVAL_TIME, num_attr,
+				 max_attr_size),
+			"%H:%M:%S", &arr_time);
+		time_t tmp = substr_time(arr_time, dep_time);
+		if (tmp > max_time)
+			max_time = tmp;
+	}
+	free(lines);
+	free(chunk);
+	return max_time;
+}
+
+// help from https://stackoverflow.com/questions/12939279/mpi-reading-from-a-text-file
+// is hosted under a permissive licence, ty Jonathan Dursi :)
+int
+parprocess(MPI_File *in, const int rank, const int size)
+{
+	// reads revelant lines from file to chunk.
+	// IN OUR CASE we will use overlap to reach EOF of this line. 
+	// Duplicates dont matter in our case ; res will be the same either way.
+	size_t proc_size, total_size, total_size_overlap;
+	char *chunk;
+	MPI_Offset globalstart;
+	MPI_Offset globalend;
+	MPI_Offset filesize;
+
+	MPI_File_get_size(*in, &filesize);
+	filesize--; /* get rid of text file eof */
+	proc_size = filesize / size;
+	globalstart = rank * proc_size;
+	globalend = globalstart + proc_size - 1;
+	if (rank == size - 1)
+		globalend = filesize - 1;
+
+	/* add overlap to the end of everyone's chunk except last
+	 * proc... */
+	size_t globalend_overlap = globalend;
+	if (rank != size - 1)
+		globalend_overlap += OVERLAP;
+
+	total_size_overlap = globalend_overlap - globalstart + 1;
+	total_size = globalend - globalstart + 1;
+
+	/* allocate memory, filled with 0 */
+	chunk = calloc(1, total_size);
+	printf("[PARPROCESS] begin\n");
+
+	ssize_t err;
+	{
+		err = MPI_File_read_at_all_begin(*in, globalstart, chunk,
+			total_size, MPI_CHAR);
+		if (err) {
+			printf("error %lu\n", err);
 			MPI_Finalize();
 		}
+		err = MPI_File_read_at_all_end(*in, chunk, MPI_STATUS_IGNORE);
+		if (err) {
+			printf("error %lu\n", err);
+			MPI_Finalize();
+		}
+	}
 
+
+	// fills the first incoherent bytes with \0
+	//size_t k = 0;
+	//if (rank != 0) { // first has no incoherece at begining
+	//	for (; chunk[k] != '\r' && chunk[k] != '\n';
+	//		++k) // get number of incoherent bytes :)
+	//		;
+	//	// reset
+
+	//	memmove(chunk, chunk + k, total_size); // - 2: dont count \n\r
+	//}
+
+	// fill char after next EOL wiht \0 ; starting from proc_size to end of
+	// overlap
+	//if (rank != size) { // last doesnt have padding, dont check it
+	//	for (; (chunk[globalend] != '\n' && chunk[globalend] != '\r') &&
+	//		globalend < globalend_overlap;
+	//		++globalend)
+	//		;
+	//	memset(chunk + globalend, '\0', OVERLAP);
+	//	//
+	//}
+	//chunk[total_size_overlap] = '\0'; // just to be sure!
+
+	int max = do_map(chunk, total_size);
+	printf("[PARPROCESS] end, max: %d\n", max);
+
+	return max;
+}