Added useful comments.

I recently found out that `p` being prime, while `p > 3`, then
`p = 6*k (+/-) 1`.

.gitignore

@@ -1,6 +1,6 @@
-# Ignore build files
-build/*
-!build/.keep
+# Ignore binary files
+*.o
+indivisible
 
 # Ignore vim temporary files
 *.sw[a-z]

CHANGELOG

@@ -37,6 +37,6 @@ Change Log
   - Allow searching for the nth prime number
   - Clearing some memory leaks
  - v2.0: Linked List
-  - Implement linked list for faster addition to list.
-  - Multi-Processor support (MPI).
   - Code cleanup.
+  - Replace OpenMP code with OpenMPI.
+  - Use linked list for prime storage.

CMakeLists.txt

@@ -1,66 +0,0 @@
-# Copyright (C) 2017  Ortega Froysa, Nicolás <deathsbreed@themusicinnoise.net>
-# Author: Ortega Froysa, Nicolás <deathsbreed@themusicinnoise.net>
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-cmake_minimum_required(VERSION 3.0)
-project(Indivisible C)
-
-set(TARGET_NAME indivisible)
-set(TARGET_VERSION "v2.0")
-
-if(NOT CMAKE_BUILD_TYPE)
-	set(CMAKE_BUILD_TYPE "release")
-endif()
-string(TOLOWER ${CMAKE_BUILD_TYPE} CMAKE_BUILD_TYPE)
-message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")
-
-set(CMAKE_MODULE_PATH
-	${CMAKE_MODULE_PATH}
-	${CMAKE_SOURCE_DIR}/cmake/)
-
-find_package(GMP REQUIRED)
-find_package(MPI REQUIRED)
-
-include_directories(
-	${MPI_C_INCLUDE_PATH}
-	${GMP_INCLUDE_DIR})
-
-set(SRCS
-	"src/linked_list.c"
-	"src/main.c")
-
-# Define the C flags.
-set(CMAKE_C_FLAGS "-std=gnu99 ${MPI_C_COMPILE_FLAGS} -Wall -Wextra -Werror -Wfatal-errors -Wmissing-declarations -pedantic-errors")
-set(CMAKE_C_FLAGS_DEBUG "-g -O0")
-set(CMAKE_C_FLAGS_RELEASE "-O3")
-set(CMAKE_C_FLAGS_RELWITHDEBINFO "-g -O3")
-set(CMAKE_C_FLAGS_MINSIZEREL "-Os")
-
-if(NOT CMAKE_BUILD_TYPE MATCHES "debug" AND NOT CMAKE_BUILD_TYPE MATCHES "relwithdebinfo")
-	add_definitions("-DNDEBUG")
-else()
-	add_definitions("-DDEBUG")
-endif()
-
-add_definitions("-DVERSION=\"${TARGET_VERSION}\"")
-
-add_executable(${TARGET_NAME} ${SRCS})
-
-target_link_libraries(${TARGET_NAME}
-	${MPI_C_LIBRARIES}
-	${GMP_LIBRARY})
-
-install(TARGETS ${TARGET_NAME}
-	RUNTIME DESTINATION "bin")

LICENSE

@@ -631,8 +631,8 @@ to attach them to the start of each source file to most effectively
 state the exclusion of warranty; and each file should have at least
 the "copyright" line and a pointer to where the full notice is found.
 
-    {one line to give the program's name and a brief idea of what it does.}
-    Copyright (C) {year}  {name of author}
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -652,7 +652,7 @@ Also add information on how to contact you by electronic and paper mail.
   If the program does terminal interaction, make it output a short
 notice like this when it starts in an interactive mode:
 
-    {project}  Copyright (C) {year}  {fullname}
+    <program>  Copyright (C) <year>  <name of author>
     This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.

Makefile

@@ -0,0 +1,48 @@
+# Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+# Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+CC=mpicc
+DEBUG=0
+PREFIX=/usr/local
+INCFLAGS=
+LDFLAGS=-lgmp
+DEFS=-DVERSION=\"2.0\" -DAPP_NAME=\"Indivisible\"
+CFLAGS=$(INCFLAGS) $(DEFS) -std=c99 -Wall -Wextra -Wfatal-errors -Werror
+HDRS=src/globals.h src/llist.h
+OBJS=src/llist.o src/main.o src/prime_test.o
+
+ifeq ($(DEBUG),1)
+	CFLAGS+=-g -O0 -DDEBUG
+else
+	CFLAGS+=-O2 -DNDEBUG
+endif
+
+%.o:%.c $(HDRS)
+	$(CC) -c -o $@ $< $(CFLAGS)
+
+indivisible: $(OBJS)
+	$(CC) -o $@ $^ $(LDFLAGS)
+
+.PHONY: clean distclean install
+
+clean:
+	$(RM) $(OBJS)
+
+distclean: clean
+	$(RM) indivisible
+
+install: indivisible
+	install -m 755 indivisible $(PREFIX)/bin/

README

@@ -1,32 +1,34 @@
 ===================
 *** Indivisible ***
 ===================
-Indivisible is a parallelized prime number generator written in C.
+A parallelized prime number generator written in C. It uses a bignum
+library as well as OpenMPI for parallelization.
 
 # Building
 ----------
-There are multiple dependencies to install before compiling the project:
+## Dependencies
+The dependencies for compiling are minimal, and should be available
+on most UNIX-like systems:
+ - GNU Make
+ - GNU Multi-Precision Arithmetics Library (GMP)
+ - OpenMPI
 
- - CMake build system
- - GNU Multi-Precision Arithmetics Library
-
-Once the dependencies are installed you can compile by running the following
-from the root directory of the project:
-
-  cd build/
-  cmake ..
-  make
-
-This will create a release build, to build with debug options append the
-`-DCMAKE_BUILD_TYPE=debug' flag to the `cmake' command.
+## Compiling
+To compile you simply need to run the `make` command, which will
+create the `indivisible` binary file. Additionally you can set the
+following flags by appending them to the `make` command:
+ - `DEBUG=<1|0>`: whether to create a debug or release build. (0 by
+   default)
+ - `PREFIX=<path>`: what base prefix to install the binaries at.
+   (`/usr/local` by default)
 
 # Contributing
 --------------
-To contribute to indivisible you can send patch files to my e-mail[0].
-
-[0] nortega@themusicinnoise.net
+To contribute to the project, please follow the same coding style you
+see in the current code base. Then, either submit a pull request or send
+a patch file to <nicolas@ortegas.org>.
 
 # License
 ---------
-This project is licensed under the GNU General Public License version 3 or
-greater (see `LICENSE' for more information).
+This project is licensed under the terms & conditions of the GNU General
+Public License version 3 or greater (see `LICENSE` file).

cmake/FindGMP.cmake

@@ -1,24 +0,0 @@
-# SOURCE: http://stackoverflow.com/questions/29307862/error-linking-gmp-library
-set(GMP_PREFIX "" CACHE PATH "path ")
-
-find_path(GMP_INCLUDE_DIR gmp.h gmpxx.h
-	PATHS ${GMP_PREFIX}/include /usr/include /usr/local/include )
-
-find_library(GMP_LIBRARY NAMES gmp libgmp
-	PATHS ${GMP_PREFIX}/lib /usr/lib /usr/local/lib)
-
-
-if(GMP_INCLUDE_DIR AND GMP_LIBRARY)
-	get_filename_component(GMP_LIBRARY_DIR ${GMP_LIBRARY} PATH)
-	set(GMP_FOUND TRUE)
-endif()
-
-if(GMP_FOUND)
-	if(NOT GMP_FIND_QUIETLY)
-		MESSAGE(STATUS "Found GMP: ${GMP_LIBRARY}")
-	endif()
-else()
-	if(GMP_FIND_REQUIRED)
-		message(FATAL_ERROR "Could not find GMP")
-	endif()
-endif()

src/global.h

@@ -1,61 +0,0 @@
-/*
- * Copyright (C) 2018  Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
- * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#pragma once
-
-#ifndef VERSION
-#	define VERSION "version"
-#endif
-
-/* argp variables */
-const char *argp_program_version = VERSION;
-const char *argp_program_bug_address = "<nortega@themusicinnoise.net>";
-
-/* argp options */
-static char desc[] = "A parallelized prime number generator.";
-/*static char args_doc[] = "--count=<number> [--verbose]";*/
-static struct argp_option opts[] = {
-	{ "count", 'c', "number", 0, "The number of primes to generate (default is 1000)", 0},
-	{ "verbose", 'v', 0, 0, "Print out discovered primes", 0 },
-	{ 0 }
-};
-
-struct args {
-	size_t count;
-	int verbose;
-};
-
-static error_t parse_opt(int key, char *arg, struct argp_state *state) {
-	struct args *args = state->input;
-	switch(key)
-	{
-		case 'c':
-			args->count = (size_t)atol(arg);
-			break;
-		case 'v':
-			args->verbose = 1;
-			break;
-		case ARGP_KEY_ARG:
-			return 0;
-		default:
-			return ARGP_ERR_UNKNOWN;
-	}
-	return 0;
-}
-
-static struct argp argp = { opts, parse_opt, 0, desc, 0, 0, 0 };

src/globals.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#ifndef APP_NAME
+#define APP_NAME "app name"
+#endif
+
+#ifndef VERSION
+#define VERSION "version"
+#endif

src/llist.c

@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2018  Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
- * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,50 +16,46 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "linked_list.h"
+#include "llist.h"
 
 #include <stdlib.h>
+#include <stdio.h>
 
 void llist_init(struct llist *list) {
-	list->size = 0;
 	list->first = NULL;
 	list->last = NULL;
+	list->size = 0;
 }
 
-int llist_add(struct llist *list, mpz_t num) {
-	struct llist_item *item =
+void llist_deinit(struct llist *list) {
+	struct llist_item *aux = list->first;
+	while(aux)
+	{
+		mpz_clear(aux->n);
+		struct llist_item *tmp = aux;
+		aux = aux->next;
+		free(tmp);
+	}
+}
+
+int llist_insert(struct llist *list, mpz_t n) {
+	struct llist_item *aux =
 		malloc(sizeof(struct llist_item));
-	if(!item)
+	if(!aux)
+	{
+		fprintf(stderr, "ERROR llist_insert(): failed to allocate memory");
 		return 0;
-
-	mpz_init(item->num);
-	mpz_set(item->num, num);
-
-	if(!(list->first))
-	{
-		list->first = item;
-		list->last = item;
-	}
-	else
-	{
-		list->last->next = item;
-		list->last = item;
 	}
+	aux->prev = list->last;
+	aux->next = NULL;
+	// TODO: check time complexity of these GMP functions
+	mpz_init(aux->n);
+	mpz_set(aux->n, n);
+
+	if(!list->first)
+		list->first = aux;
+	list->last = aux;
 	list->size++;
 
 	return 1;
 }
-
-void llist_deinit(struct llist *list) {
-	struct llist_item *i = list->first;
-
-	while(i)
-	{
-		mpz_clear(i->num);
-		struct llist_item *next = i->next;
-		free(i);
-		i = next;
-	}
-
-	list->size = 0;
-}

src/llist.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <gmp.h>
+
+struct llist_item {
+	mpz_t n; // the number stored
+	struct llist_item *next; // the next element in the list
+	struct llist_item *prev; // the previous element in the list
+};
+
+struct llist {
+	struct llist_item *first; // first element of the list
+	struct llist_item *last; // last element of the list
+	size_t size; // number of elements in the list
+};
+
+/*
+ * initialize an empty linked list where `first` and `last` are
+ * equal to NULL and `size` is 0.
+ */
+void llist_init(struct llist *list);
+
+/*
+ * free all space allocated to the list.
+ */
+void llist_deinit(struct llist *list);
+
+/*
+ * insert an item at the end of the linked list with value `n`.
+ *
+ * returns 1 on success, 0 on failure.
+ */
+int llist_insert(struct llist *list, mpz_t n);
+/*
+ * insert an item in the linked list in a sorted position.
+ *
+ * returns 1 on success, 0 on failure.
+ */
+int llist_sorted_insert(struct llist *list, mpz_t n);

src/main.c

@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2018  Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
- * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -16,75 +16,55 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "globals.h"
+#include "llist.h"
+#include "prime_test.h"
+
+#include <signal.h>
 #include <stdio.h>
-#include <stdlib.h>
-#include <argp.h>
 #include <gmp.h>
 
-#include "global.h"
-#include "linked_list.h"
+int run = 1;
 
-int main(int argc, char *argv[]) {
-	struct args args = { 1000, 0 };
+void quit_signal(int signum) {
+	printf("Received signal %d. Ending process...\n", signum);
+	run = 0;
+}
 
-	argp_parse(&argp, argc, argv, 0, 0, &args);
+int main() {
+	printf("%s v%s\n", APP_NAME, VERSION);
 
-	if(args.count == 0)
-	{
-		fprintf(stderr, "ERROR: count must be larger than 0.\n");
-		return 1;
-	}
+	signal(SIGINT, quit_signal);
 
-	struct llist prime_list;
-	llist_init(&prime_list);
+	mpz_t test_base; // number used to get tested numbers
+	mpz_t p0, p1; // numbers to be tested for prime-ness.
+
+	mpz_inits(test_base, p0, p1, NULL);
+	mpz_set_ui(test_base, 6); // test_base = 6*k
 
-	{
-		// initialize the list with 2
-		mpz_t tmp;
-		mpz_init(tmp);
-		mpz_set_ui(tmp, 2);
-		llist_add(&prime_list, tmp);
-		mpz_clear(tmp);
-		if(args.verbose)
 	puts("2");
-	}
+	puts("3");
 
-	mpz_t aux;
-	mpz_init(aux);
-	mpz_set_ui(aux, 3);
-	while(prime_list.size < args.count)
+	while(run)
 	{
-		struct llist_item *item = prime_list.first;
-		int is_prime = 1;
+		mpz_sub_ui(p0, test_base, 1); // p0 = test_base - 1
+		mpz_add_ui(p1, test_base, 1); // p0 = test_base + 1
 
-		mpz_t root;
-		mpz_init(root);
-		mpz_sqrt(root, aux);
-		while(item && mpz_cmp(item->num, root) < 0)
+		if(test_prime(p0))
 		{
-			if(mpz_divisible_p(aux, item->num))
-			{
-				is_prime = 0;
-				break;
-			}
-			item = item->next;
-		}
-		if(is_prime)
-		{
-			llist_add(&prime_list, aux);
-			if(args.verbose)
-			{
-				mpz_out_str(stdout, 10, aux);
+			mpz_out_str(stdout, 10, p0);
 			printf("\n");
 		}
-		}
-		mpz_add_ui(aux, aux, 2);
-	}
-
-	printf("The %zu prime is ", prime_list.size);
-	mpz_out_str(stdout, 10, prime_list.last->num);
+		if(test_prime(p1))
+		{
+			mpz_out_str(stdout, 10, p1);
 			printf("\n");
+		}
+
+		mpz_add_ui(test_base, test_base, 6); // k += 1
+	}
+
+	mpz_clears(test_base, p0, p1, NULL);
 
-	llist_deinit(&prime_list);
 	return 0;
 }

src/prime_test.c

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "prime_test.h"
+
+int test_prime(const mpz_t p) {
+	mpz_t psqrt;
+	mpz_t aux;
+	mpz_inits(psqrt, aux, NULL);
+	mpz_sqrt(psqrt, p);
+	int is_prime = 1;
+	for(mpz_set_ui(aux, 5); mpz_cmp(aux, psqrt) <= 0; mpz_add_ui(aux, aux, 2))
+	{
+		if(mpz_divisible_p(p, aux))
+		{
+			is_prime = 0;
+			break;
+		}
+	}
+
+	mpz_clears(psqrt, aux, NULL);
+
+	return is_prime;
+}

src/prime_test.h

@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2018  Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
- * Author: Ortega Froysa, Nicolás <nortega@themusicinnoise.net>
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,18 +20,8 @@
 
 #include <gmp.h>
 
-struct llist_item {
-	mpz_t num;
-	struct llist_item *prev;
-	struct llist_item *next;
-};
-
-struct llist {
-	struct llist_item *first;
-	struct llist_item *last;
-	size_t size;  // size of the list
-};
-
-void llist_init(struct llist *list);
-int llist_add(struct llist *list, mpz_t num);
-void llist_deinit(struct llist *list);
+/*
+ * checks to see if the number `p` is prime, returning 1 if it is and 0
+ * if it is not.
+ */
+int test_prime(const mpz_t p);