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/* Model of a forest fire - a 2D rectangular grid of trees is initialized
with one random tree caught on fire. At each time step, trees that are not
on fire yet check their neighbors to the north, east, south, and west, and
if any of them are on fire, the tree catches fire with some percent chance.
The model runs for a certain number of time steps, which can be controlled
by the user. At the end of the simulation, the program outputs the total
percentage of trees burned. Tree data can also be output at each time step
if a filename is provided by the user.
*/
/* Author: Aaron Weeden, Shodor, 2015 */
/* Naming convention:
ALL_CAPS for constants
CamelCase for globals and functions
lowerCase for locals
*/
#include <stdbool.h> /* bool type */
#include <stdio.h> /* printf() */
#include <stdlib.h> /* atoi(), exit(), EXIT_FAILURE, malloc(), free(),
random() */
#include <string.h> /* strcpy() */
#include <unistd.h> /* getopt() */
/* Define descriptions of command line options */
#define N_ROWS_DESCR \
"The forest has this many rows of trees (positive integer)"
#define N_COLS_DESCR \
"The forest has this many columns of trees (positive integer)"
#define BURN_PROB_DESCR \
"Chance of catching fire if next to burning tree (positive integer [0..100])"
#define N_MAX_BURN_STEPS_DESCR \
"A burning tree stops burning after this many time steps (positive integer bigger than 1)"
#define N_STEPS_DESCR \
"Run for this many time steps (positive integer)"
#define RAND_SEED_DESCR \
"Seed value for the random number generator (positive integer)"
#define OUTPUT_FILENAME_DESCR \
"Filename to output tree data at each time step (file must not already exist)"
#define IS_RAND_FIRST_TREE_DESCR \
"Start the first on a random first tree as opposed to the middle tree"
/* Define default values for simulation parameters - each of these parameters
can also be changed later via user input */
#define N_ROWS_DEFAULT 21
#define N_COLS_DEFAULT N_ROWS_DEFAULT
#define BURN_PROB_DEFAULT 100
#define N_MAX_BURN_STEPS_DEFAULT 2
#define N_STEPS_DEFAULT N_ROWS_DEFAULT
#define RAND_SEED_DEFAULT 1
#define DEFAULT_IS_OUTPUTTING_EACH_STEP false
#define DEFAULT_IS_RAND_FIRST_TREE false
/* Define characters used on the command line to change the values of input
parameters */
#define N_ROWS_CHAR 'r'
#define N_COLS_CHAR 'c'
#define BURN_PROB_CHAR 'b'
#define N_MAX_BURN_STEPS_CHAR 'm'
#define N_STEPS_CHAR 't'
#define RAND_SEED_CHAR 's'
#define OUTPUT_FILENAME_CHAR 'o'
#define IS_RAND_FIRST_TREE_CHAR 'f'
/* Define options string used by getopt() - a colon after the character means
the parameter's value is specified by the user */
const char GETOPT_STRING[] = {
N_ROWS_CHAR, ':',
N_COLS_CHAR, ':',
BURN_PROB_CHAR, ':',
N_MAX_BURN_STEPS_CHAR, ':',
N_STEPS_CHAR, ':',
RAND_SEED_CHAR, ':',
OUTPUT_FILENAME_CHAR, ':',
IS_RAND_FIRST_TREE_CHAR
};
/* Define a mapping from the row and column of a given tree in a forest with
boundaries to the index of that tree in a 1D array that includes
boundaries */
#define TREE_MAP(row, col, nColsPlusBounds) ((row) * (nColsPlusBounds) + (col))
/* Define a mapping from the row and column of a given tree in a forest with
boundaries to the index of that tree in a 1D array that does not include
boundaries */
#define NEW_TREE_MAP(row, col, nCols) ((row - 1) * (nCols) + (col - 1))
/* Declare global parameters */
int NRows = N_ROWS_DEFAULT;
int NCols = N_COLS_DEFAULT;
int BurnProb = BURN_PROB_DEFAULT;
int NMaxBurnSteps = N_MAX_BURN_STEPS_DEFAULT;
int NSteps = N_STEPS_DEFAULT;
int RandSeed = RAND_SEED_DEFAULT;
bool IsOutputtingEachStep = DEFAULT_IS_OUTPUTTING_EACH_STEP;
bool IsRandFirstTree = DEFAULT_IS_RAND_FIRST_TREE;
char *OutputFilename;
/* Declare other needed global variables */
bool AreParamsValid = true; /* Do the model parameters have valid values? */
int NTrees; /* Total number of trees in the forest */
int NRowsPlusBounds; /* Number of rows of trees plus the boundary rows */
int NColsPlusBounds; /* Number of columns of trees plus the boundary columns */
int NTreesPlusBounds; /* Total number of trees plus the boundaries */
int MiddleRow; /* The tree in the middle is here. If an even number of rows,
this tree is just below the middle */
int MiddleCol; /* The tree in the middle is here. If an even number of cols,
this tree is just to the right of the middle */
int CurStep; /* The current time step */
int NBurnedTrees; /* The total number of burned trees */
char ExeName[32]; /* The name of the program executable */
int NMaxBurnStepsDigits; /* The number of digits in the max burn steps; used for
outputting tree data */
int *Trees; /* 1D tree array, contains a boundary around the outside of the
forest so the same neighbor checking algorithm can be used on
all cells */
int *NewTrees; /* Copy of 1D tree array - used so that we don't update the
forest too soon as we are deciding which new trees
should burn -- does not contain boundary */
FILE *OutputFile; /* For outputting tree data to a file */
/* DECLARE FUNCTIONS */
/* Prints out a description of an integer command line option
@param optChar The character used to specify the option
@param optDescr The description of the option
@param optDefault The default value of the option
*/
void DescribeOptionInt(const char optChar, const char *optDescr,
const int optDefault) {
fprintf(stderr, "-%c : \n\t%s\n\tdefault: %d\n", optChar, optDescr,
optDefault);
}
/* Prints out a description of a string command line option
@param optChar The character used to specify the option
@param optDescr The description of the option
*/
void DescribeOptionNoDefault(const char optChar, const char *optDescr) {
fprintf(stderr, "-%c : \n\t%s\n", optChar, optDescr);
}
/* Print an error message
@param errorMsg Buffer containing the message
*/
void PrintError(const char *errorMsg) {
fprintf(stderr, "%s", errorMsg);
AreParamsValid = false;
}
/* Display to the user what options are available for running the program and
exit the program in failure
@param errorMsg The error message to print
*/
void PrintUsageAndExit() {
fprintf(stderr, "Usage: ");
fprintf(stderr, "%s [OPTIONS]\n", ExeName);
fprintf(stderr, "Where OPTIONS can be any of the following:\n");
DescribeOptionInt(N_ROWS_CHAR, N_ROWS_DESCR, N_ROWS_DEFAULT);
DescribeOptionInt(N_COLS_CHAR, N_COLS_DESCR, N_COLS_DEFAULT);
DescribeOptionInt(BURN_PROB_CHAR, BURN_PROB_DESCR, BURN_PROB_DEFAULT);
DescribeOptionInt(N_MAX_BURN_STEPS_CHAR, N_MAX_BURN_STEPS_DESCR,
N_MAX_BURN_STEPS_DEFAULT);
DescribeOptionInt(N_STEPS_CHAR, N_STEPS_DESCR, N_STEPS_DEFAULT);
DescribeOptionInt(RAND_SEED_CHAR, RAND_SEED_DESCR, RAND_SEED_DEFAULT);
DescribeOptionNoDefault(OUTPUT_FILENAME_CHAR, OUTPUT_FILENAME_DESCR);
DescribeOptionNoDefault(IS_RAND_FIRST_TREE_CHAR,
IS_RAND_FIRST_TREE_DESCR);
exit(EXIT_FAILURE);
}
/* Assert that a user's input value is an integer. If it is not, print
a usage message and an error message and exit the program.
@param param The user's input value
@param optChar The character used to specify the user's input value
*/
void AssertInteger(int param, const char optChar) {
char errorStr[64];
/* Get the user's input value, assume floating point */
const float floatParam = atof(optarg);
/* Make sure positive and integer */
if (floatParam != param) {
sprintf(errorStr, "ERROR: value for -%c must be an integer\n",
optChar);
PrintError(errorStr);
}
}
/* Assert that a user's input value is a positive integer. If it is not, print
a usage message and an error message and exit the program.
@param param The user's input value
@param optChar The character used the specify the user's input value
*/
void AssertPositiveInteger(int param, const char optChar) {
char errorStr[64];
/* Get the user's input value, assume floating point */
const float floatParam = atof(optarg);
/* Make sure positive and integer */
if (param < 1 || floatParam != param) {
sprintf(errorStr, "ERROR: value for -%c must be positive integer\n",
optChar);
PrintError(errorStr);
}
}
/* Assert that a user's input value is bigger than a value. If it is
not, print a usage message and an error message and exit the program.
@param param The user's input value
@param low The value the parameter needs to be bigger than
@param optChar The character used the specify the user's input value
*/
void AssertBigger(int param, const int val, const char optChar) {
char errorStr[64];
if (param <= val) {
sprintf(errorStr,
"ERROR: value for -%c must be bigger than %d\n", optChar, val);
PrintError(errorStr);
}
}
/* Assert that a user's input value is between two values, inclusive. If it is
not, print a usage message and an error message and exit the program.
@param param The user's input value
@param low The lowest value the parameter can be
@param high The highest value the parameter can be
@param optChar The character used the specify the user's input value
*/
void AssertBetweenInclusive(int param, const int low, const int high,
const char optChar) {
char errorStr[64];
if (param < low || param > high) {
sprintf(errorStr,
"ERROR: value for -%c must be between %d and %d, inclusive\n",
optChar, low, high);
PrintError(errorStr);
}
}
/* Exit if a file already exists */
void AssertFileDNE(const char *filename) {
char errorStr[64];
if (access(filename, F_OK) != -1) {
sprintf(errorStr,
"ERROR: File '%s' already exists\n", filename);
PrintError(errorStr);
}
}
/* Allow the user to change simulation parameters via the command line
@param argc The number of command line arguments to parse
@param argv The array of command line arguments to parse
*/
void GetUserOptions(const int argc, char **argv) {
char c; /* Loop control variable */
/* Loop over argv, setting parameter values given */
while ((c = getopt(argc, argv, GETOPT_STRING)) != -1) {
switch(c) {
case N_ROWS_CHAR:
NRows = atoi(optarg);
AssertPositiveInteger(NRows, N_ROWS_CHAR);
break;
case N_COLS_CHAR:
NCols = atoi(optarg);
AssertPositiveInteger(NCols, N_COLS_CHAR);
break;
case BURN_PROB_CHAR:
BurnProb = atoi(optarg);
AssertInteger(BurnProb, BURN_PROB_CHAR);
AssertBetweenInclusive(BurnProb, 0, 100, BURN_PROB_CHAR);
break;
case N_MAX_BURN_STEPS_CHAR:
NMaxBurnSteps = atoi(optarg);
AssertPositiveInteger(NMaxBurnSteps, N_MAX_BURN_STEPS_CHAR);
AssertBigger(NMaxBurnSteps, 1, N_MAX_BURN_STEPS_CHAR);
break;
case N_STEPS_CHAR:
NSteps = atoi(optarg);
AssertPositiveInteger(NSteps, N_STEPS_CHAR);
break;
case RAND_SEED_CHAR:
RandSeed = atoi(optarg);
AssertPositiveInteger(RandSeed, RAND_SEED_CHAR);
break;
case OUTPUT_FILENAME_CHAR:
IsOutputtingEachStep = true;
OutputFilename = optarg;
break;
case IS_RAND_FIRST_TREE_CHAR:
IsRandFirstTree = true;
break;
case '?':
default:
PrintError("ERROR: illegal option\n");
PrintUsageAndExit();
}
}
if (IsOutputtingEachStep) {
/* Make sure the output file does not exist (DNE) */
AssertFileDNE(OutputFilename);
}
}
/* Allocate dynamic memory */
void AllocateMemory() {
Trees = (int*)malloc(NTreesPlusBounds * sizeof(int));
NewTrees = (int*)malloc( NTrees * sizeof(int));
}
/* Generate a random integer between [min..max)
@param min Smallest integer to generate
@param max 1 more than the biggest integer to generate
@return random integer
*/
int RandBetween(const int min, const int max) {
return min + (random() % (max - min));
}
/* Light a random tree on fire, set all other trees to be not burning */
void InitData() {
int row;
int col;
/* Set all trees as having burned for 0 time steps */
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
Trees[ TREE_MAP(row, col, NColsPlusBounds)] =
NewTrees[NEW_TREE_MAP(row, col, NCols)] = 0;
}
}
/* Set the boundaries as burnt out */
for (row = 0; row < NRowsPlusBounds; row++) {
/* Left */
Trees[TREE_MAP(row, 0, NColsPlusBounds)] = NMaxBurnSteps;
/* Top/Bottom */
if ((row == 0) || (row == NRows + 1)) {
for (col = 1; col < NCols + 1; col++) {
Trees[TREE_MAP(row, col, NColsPlusBounds)] = NMaxBurnSteps;
}
}
/* Right */
Trees[TREE_MAP(row, NCols + 1, NColsPlusBounds)] = NMaxBurnSteps;
}
if (IsRandFirstTree) {
/* Light a random tree on fire */
row = RandBetween(1, NRows + 1);
col = RandBetween(1, NCols + 1);
}
else {
/* Light the middle tree on fire */
row = MiddleRow + 1;
col = MiddleCol + 1;
}
Trees[ TREE_MAP(row, col, NColsPlusBounds)] =
NewTrees[NEW_TREE_MAP(row, col, NCols)] = 1;
NBurnedTrees++;
}
/* Output tree data for the current time step */
void OutputData() {
int row;
int col;
char buf[64];
/* Write the header for the current time step */
sprintf(buf, "Time step %d\n", CurStep);
fprintf(OutputFile, "%s", buf);
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
sprintf(buf, "%*d ",
NMaxBurnStepsDigits, Trees[TREE_MAP(row, col, NColsPlusBounds)]);
fprintf(OutputFile, "%s", buf);
}
fprintf(OutputFile, "\n");
}
/* Write the newline between time steps */
fprintf(OutputFile, "\n");
}
/* Return whether a given tree has burnt out
@param row The row index of the tree
@param col The column index of the tree
@return Whether the tree in the given row and column has burnt out
*/
bool IsBurntOut(const int row, const int col) {
return Trees[TREE_MAP(row, col, NColsPlusBounds)] >= NMaxBurnSteps;
}
/* Return whether a given tree is on fire
@param row The row index of the tree
@param col The column index of the tree
@return Whether the tree in the given row and column is on fire
*/
bool IsOnFire(const int row, const int col) {
return Trees[TREE_MAP(row, col, NColsPlusBounds)] > 0 &&
!IsBurntOut(row, col);
}
/* For trees already burning, increment the number of time steps they have
burned
*/
void ContinueBurning() {
int row;
int col;
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
if (IsOnFire(row, col)) {
NewTrees[NEW_TREE_MAP(row, col, NCols)] =
Trees[ TREE_MAP(row, col, NColsPlusBounds)] + 1;
}
}
}
}
/* Find trees that are not on fire yet and try to catch them on fire from
burning neighbor trees
*/
void BurnNew() {
int row;
int col;
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
if (!IsOnFire(row, col) && !IsBurntOut(row, col)) {
/* Check neighbors */
/* Top */
if ((IsOnFire(row-1, col) ||
/* Left */
IsOnFire(row, col-1) ||
/* Bottom */
IsOnFire(row+1, col) ||
/* Right */
IsOnFire(row, col+1)) &&
/* Apply random chance */
(RandBetween(0, 100) < BurnProb)) {
/* Catch the tree on fire */
NewTrees[NEW_TREE_MAP(row, col, NCols)] = 1;
NBurnedTrees++;
}
}
}
}
}
/* Copy new tree data into old tree data */
void AdvanceTime() {
int row;
int col;
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
Trees[ TREE_MAP(row, col, NColsPlusBounds)] =
NewTrees[NEW_TREE_MAP(row, col, NCols)];
}
}
}
/* Free allocated memory */
void FreeMemory() {
free(NewTrees);
free(Trees);
}
/* @param argc The number of command line arguments
@param argv String of command line arguments
*/
int main(int argc, char **argv) {
/* Set the program executable name */
strcpy(ExeName, argv[0]);
/* Allow the user to change simulation parameters via the command line */
GetUserOptions(argc, argv);
if (!AreParamsValid) {
/* Model parameters are not valid; exit early */
PrintUsageAndExit();
}
if (IsOutputtingEachStep) {
/* Open the output file */
OutputFile = fopen(OutputFilename, "w");
}
/* Do some calculations before splitting up the rows */
NTrees = NRows * NCols;
NRowsPlusBounds = NRows + 2;
NColsPlusBounds = NCols + 2;
NTreesPlusBounds = NRowsPlusBounds * NColsPlusBounds;
MiddleRow = NRows / 2;
MiddleCol = NCols / 2;
/* Allocate dynamic memory for the 1D tree arrays */
AllocateMemory();
/* Seed the random number generator */
srandom(RandSeed);
/* Initialize number of burned trees */
NBurnedTrees = 0;
/* Light a random tree on fire, set all other trees to be not burning */
InitData();
/* Start the simulation looping for the specified number of time steps */
for (CurStep = 0; CurStep < NSteps; CurStep++) {
if (IsOutputtingEachStep) {
/* Output tree data for the current time step */
OutputData();
}
/* For trees already burning, increment the number of time steps they have
burned */
ContinueBurning();
/* Find trees that are not on fire yet and try to catch them on fire from
burning neighbor trees */
BurnNew();
/* Copy new tree data into old tree data */
AdvanceTime();
}
/* Print the total percentage of trees burned */
printf("%.2f%% of the trees were burned\n",
(100.0 * NBurnedTrees) / NTrees);
if (IsOutputtingEachStep) {
/* Close the output file */
fclose(OutputFile);
}
/* Free allocated memory */
FreeMemory();
return 0;
}
|
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/* Model of a forest fire - a 2D rectangular grid of trees is initialized
with one random tree caught on fire. At each time step, trees that are not
on fire yet check their neighbors to the north, east, south, and west, and
if any of them are on fire, the tree catches fire with some percent chance.
The model runs for a certain number of time steps, which can be controlled
by the user. At the end of the simulation, the program outputs the total
percentage of trees burned. Tree data can also be output at each time step
if a filename is provided by the user.
*/
/* Author: Aaron Weeden, Shodor, 2015 */
/* Naming convention:
ALL_CAPS for constants
CamelCase for globals and functions
lowerCase for locals
*/
#include <stdbool.h> /* bool type */
#include <stdio.h> /* printf() */
#include <stdlib.h> /* atoi(), exit(), EXIT_FAILURE, malloc(), free(),
random() */
#include <string.h> /* strcpy() */
#include <unistd.h> /* getopt() */
/* Define descriptions of command line options */
#define N_ROWS_DESCR \
"The forest has this many rows of trees (positive integer)"
#define N_COLS_DESCR \
"The forest has this many columns of trees (positive integer)"
#define BURN_PROB_DESCR \
"Chance of catching fire if next to burning tree (positive integer [0..100])"
#define N_MAX_BURN_STEPS_DESCR \
"A burning tree stops burning after this many time steps (positive integer bigger than 1)"
#define N_STEPS_DESCR \
"Run for this many time steps (positive integer)"
#define RAND_SEED_DESCR \
"Seed value for the random number generator (positive integer)"
#define OUTPUT_FILENAME_DESCR \
"Filename to output tree data at each time step (file must not already exist)"
#define IS_RAND_FIRST_TREE_DESCR \
"Start the first on a random first tree as opposed to the middle tree"
/* Define default values for simulation parameters - each of these parameters
can also be changed later via user input */
#define N_ROWS_DEFAULT 21
#define N_COLS_DEFAULT N_ROWS_DEFAULT
#define BURN_PROB_DEFAULT 100
#define N_MAX_BURN_STEPS_DEFAULT 2
#define N_STEPS_DEFAULT N_ROWS_DEFAULT
#define RAND_SEED_DEFAULT 1
#define DEFAULT_IS_OUTPUTTING_EACH_STEP false
#define DEFAULT_IS_RAND_FIRST_TREE false
/* Define characters used on the command line to change the values of input
parameters */
#define N_ROWS_CHAR 'r'
#define N_COLS_CHAR 'c'
#define BURN_PROB_CHAR 'b'
#define N_MAX_BURN_STEPS_CHAR 'm'
#define N_STEPS_CHAR 't'
#define RAND_SEED_CHAR 's'
#define OUTPUT_FILENAME_CHAR 'o'
#define IS_RAND_FIRST_TREE_CHAR 'f'
/* Define options string used by getopt() - a colon after the character means
the parameter's value is specified by the user */
const char GETOPT_STRING[] = {
N_ROWS_CHAR, ':',
N_COLS_CHAR, ':',
BURN_PROB_CHAR, ':',
N_MAX_BURN_STEPS_CHAR, ':',
N_STEPS_CHAR, ':',
RAND_SEED_CHAR, ':',
OUTPUT_FILENAME_CHAR, ':',
IS_RAND_FIRST_TREE_CHAR
};
/* Define a mapping from the row and column of a given tree in a forest with
boundaries to the index of that tree in a 1D array that includes
boundaries */
#define TREE_MAP(row, col, nColsPlusBounds) ((row) * (nColsPlusBounds) + (col))
/* Define a mapping from the row and column of a given tree in a forest with
boundaries to the index of that tree in a 1D array that does not include
boundaries */
#define NEW_TREE_MAP(row, col, nCols) ((row - 1) * (nCols) + (col - 1))
/* Declare global parameters */
int NRows = N_ROWS_DEFAULT;
int NCols = N_COLS_DEFAULT;
int BurnProb = BURN_PROB_DEFAULT;
int NMaxBurnSteps = N_MAX_BURN_STEPS_DEFAULT;
int NSteps = N_STEPS_DEFAULT;
int RandSeed = RAND_SEED_DEFAULT;
bool IsOutputtingEachStep = DEFAULT_IS_OUTPUTTING_EACH_STEP;
bool IsRandFirstTree = DEFAULT_IS_RAND_FIRST_TREE;
char *OutputFilename;
/* Declare other needed global variables */
bool AreParamsValid = true; /* Do the model parameters have valid values? */
int NTrees; /* Total number of trees in the forest */
int NRowsPlusBounds; /* Number of rows of trees plus the boundary rows */
int NColsPlusBounds; /* Number of columns of trees plus the boundary columns */
int NTreesPlusBounds; /* Total number of trees plus the boundaries */
int MiddleRow; /* The tree in the middle is here. If an even number of rows,
this tree is just below the middle */
int MiddleCol; /* The tree in the middle is here. If an even number of cols,
this tree is just to the right of the middle */
int CurStep; /* The current time step */
int NBurnedTrees; /* The total number of burned trees */
char ExeName[32]; /* The name of the program executable */
int NMaxBurnStepsDigits; /* The number of digits in the max burn steps; used for
outputting tree data */
int *Trees; /* 1D tree array, contains a boundary around the outside of the
forest so the same neighbor checking algorithm can be used on
all cells */
int *NewTrees; /* Copy of 1D tree array - used so that we don't update the
forest too soon as we are deciding which new trees
should burn -- does not contain boundary */
FILE *OutputFile; /* For outputting tree data to a file */
/* DECLARE FUNCTIONS */
/* Prints out a description of an integer command line option
@param optChar The character used to specify the option
@param optDescr The description of the option
@param optDefault The default value of the option
*/
void DescribeOptionInt(const char optChar, const char *optDescr,
const int optDefault) {
fprintf(stderr, "-%c : \n\t%s\n\tdefault: %d\n", optChar, optDescr,
optDefault);
}
/* Prints out a description of a string command line option
@param optChar The character used to specify the option
@param optDescr The description of the option
*/
void DescribeOptionNoDefault(const char optChar, const char *optDescr) {
fprintf(stderr, "-%c : \n\t%s\n", optChar, optDescr);
}
/* Print an error message
@param errorMsg Buffer containing the message
*/
void PrintError(const char *errorMsg) {
fprintf(stderr, "%s", errorMsg);
AreParamsValid = false;
}
/* Display to the user what options are available for running the program and
exit the program in failure
@param errorMsg The error message to print
*/
void PrintUsageAndExit() {
fprintf(stderr, "Usage: ");
fprintf(stderr, "%s [OPTIONS]\n", ExeName);
fprintf(stderr, "Where OPTIONS can be any of the following:\n");
DescribeOptionInt(N_ROWS_CHAR, N_ROWS_DESCR, N_ROWS_DEFAULT);
DescribeOptionInt(N_COLS_CHAR, N_COLS_DESCR, N_COLS_DEFAULT);
DescribeOptionInt(BURN_PROB_CHAR, BURN_PROB_DESCR, BURN_PROB_DEFAULT);
DescribeOptionInt(N_MAX_BURN_STEPS_CHAR, N_MAX_BURN_STEPS_DESCR,
N_MAX_BURN_STEPS_DEFAULT);
DescribeOptionInt(N_STEPS_CHAR, N_STEPS_DESCR, N_STEPS_DEFAULT);
DescribeOptionInt(RAND_SEED_CHAR, RAND_SEED_DESCR, RAND_SEED_DEFAULT);
DescribeOptionNoDefault(OUTPUT_FILENAME_CHAR, OUTPUT_FILENAME_DESCR);
DescribeOptionNoDefault(IS_RAND_FIRST_TREE_CHAR,
IS_RAND_FIRST_TREE_DESCR);
exit(EXIT_FAILURE);
}
/* Assert that a user's input value is an integer. If it is not, print
a usage message and an error message and exit the program.
@param param The user's input value
@param optChar The character used to specify the user's input value
*/
void AssertInteger(int param, const char optChar) {
char errorStr[64];
/* Get the user's input value, assume floating point */
const float floatParam = atof(optarg);
/* Make sure positive and integer */
if (floatParam != param) {
sprintf(errorStr, "ERROR: value for -%c must be an integer\n",
optChar);
PrintError(errorStr);
}
}
/* Assert that a user's input value is a positive integer. If it is not, print
a usage message and an error message and exit the program.
@param param The user's input value
@param optChar The character used the specify the user's input value
*/
void AssertPositiveInteger(int param, const char optChar) {
char errorStr[64];
/* Get the user's input value, assume floating point */
const float floatParam = atof(optarg);
/* Make sure positive and integer */
if (param < 1 || floatParam != param) {
sprintf(errorStr, "ERROR: value for -%c must be positive integer\n",
optChar);
PrintError(errorStr);
}
}
/* Assert that a user's input value is bigger than a value. If it is
not, print a usage message and an error message and exit the program.
@param param The user's input value
@param low The value the parameter needs to be bigger than
@param optChar The character used the specify the user's input value
*/
void AssertBigger(int param, const int val, const char optChar) {
char errorStr[64];
if (param <= val) {
sprintf(errorStr,
"ERROR: value for -%c must be bigger than %d\n", optChar, val);
PrintError(errorStr);
}
}
/* Assert that a user's input value is between two values, inclusive. If it is
not, print a usage message and an error message and exit the program.
@param param The user's input value
@param low The lowest value the parameter can be
@param high The highest value the parameter can be
@param optChar The character used the specify the user's input value
*/
void AssertBetweenInclusive(int param, const int low, const int high,
const char optChar) {
char errorStr[64];
if (param < low || param > high) {
sprintf(errorStr,
"ERROR: value for -%c must be between %d and %d, inclusive\n",
optChar, low, high);
PrintError(errorStr);
}
}
/* Exit if a file already exists */
void AssertFileDNE(const char *filename) {
char errorStr[64];
if (access(filename, F_OK) != -1) {
sprintf(errorStr,
"ERROR: File '%s' already exists\n", filename);
PrintError(errorStr);
}
}
/* Allow the user to change simulation parameters via the command line
@param argc The number of command line arguments to parse
@param argv The array of command line arguments to parse
*/
void GetUserOptions(const int argc, char **argv) {
char c; /* Loop control variable */
/* Loop over argv, setting parameter values given */
while ((c = getopt(argc, argv, GETOPT_STRING)) != -1) {
switch(c) {
case N_ROWS_CHAR:
NRows = atoi(optarg);
AssertPositiveInteger(NRows, N_ROWS_CHAR);
break;
case N_COLS_CHAR:
NCols = atoi(optarg);
AssertPositiveInteger(NCols, N_COLS_CHAR);
break;
case BURN_PROB_CHAR:
BurnProb = atoi(optarg);
AssertInteger(BurnProb, BURN_PROB_CHAR);
AssertBetweenInclusive(BurnProb, 0, 100, BURN_PROB_CHAR);
break;
case N_MAX_BURN_STEPS_CHAR:
NMaxBurnSteps = atoi(optarg);
AssertPositiveInteger(NMaxBurnSteps, N_MAX_BURN_STEPS_CHAR);
AssertBigger(NMaxBurnSteps, 1, N_MAX_BURN_STEPS_CHAR);
break;
case N_STEPS_CHAR:
NSteps = atoi(optarg);
AssertPositiveInteger(NSteps, N_STEPS_CHAR);
break;
case RAND_SEED_CHAR:
RandSeed = atoi(optarg);
AssertPositiveInteger(RandSeed, RAND_SEED_CHAR);
break;
case OUTPUT_FILENAME_CHAR:
IsOutputtingEachStep = true;
OutputFilename = optarg;
break;
case IS_RAND_FIRST_TREE_CHAR:
IsRandFirstTree = true;
break;
case '?':
default:
PrintError("ERROR: illegal option\n");
PrintUsageAndExit();
}
}
if (IsOutputtingEachStep) {
/* Make sure the output file does not exist (DNE) */
AssertFileDNE(OutputFilename);
}
}
/* Allocate dynamic memory */
void AllocateMemory() {
Trees = (int*)malloc(NTreesPlusBounds * sizeof(int));
NewTrees = (int*)malloc( NTrees * sizeof(int));
}
/* Generate a random integer between [min..max)
@param min Smallest integer to generate
@param max 1 more than the biggest integer to generate
@return random integer
*/
int RandBetween(const int min, const int max) {
return min + (random() % (max - min));
}
/* Light a random tree on fire, set all other trees to be not burning */
void InitData() {
int row;
int col;
/* Set all trees as having burned for 0 time steps */
#pragma omp parallel for private(col)
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
Trees[ TREE_MAP(row, col, NColsPlusBounds)] =
NewTrees[NEW_TREE_MAP(row, col, NCols)] = 0;
}
}
/* Set the boundaries as burnt out */
#pragma omp parallel for private(col)
for (row = 0; row < NRowsPlusBounds; row++) {
/* Left */
Trees[TREE_MAP(row, 0, NColsPlusBounds)] = NMaxBurnSteps;
/* Top/Bottom */
if ((row == 0) || (row == NRows + 1)) {
for (col = 1; col < NCols + 1; col++) {
Trees[TREE_MAP(row, col, NColsPlusBounds)] = NMaxBurnSteps;
}
}
/* Right */
Trees[TREE_MAP(row, NCols + 1, NColsPlusBounds)] = NMaxBurnSteps;
}
if (IsRandFirstTree) {
/* Light a random tree on fire */
row = RandBetween(1, NRows + 1);
col = RandBetween(1, NCols + 1);
}
else {
/* Light the middle tree on fire */
row = MiddleRow + 1;
col = MiddleCol + 1;
}
Trees[ TREE_MAP(row, col, NColsPlusBounds)] =
NewTrees[NEW_TREE_MAP(row, col, NCols)] = 1;
NBurnedTrees++;
}
/* Output tree data for the current time step */
void OutputData() {
int row;
int col;
char buf[64];
/* Write the header for the current time step */
sprintf(buf, "Time step %d\n", CurStep);
fprintf(OutputFile, "%s", buf);
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
sprintf(buf, "%*d ",
NMaxBurnStepsDigits, Trees[TREE_MAP(row, col, NColsPlusBounds)]);
fprintf(OutputFile, "%s", buf);
}
fprintf(OutputFile, "\n");
}
/* Write the newline between time steps */
fprintf(OutputFile, "\n");
}
/* Return whether a given tree has burnt out
@param row The row index of the tree
@param col The column index of the tree
@return Whether the tree in the given row and column has burnt out
*/
bool IsBurntOut(const int row, const int col) {
return Trees[TREE_MAP(row, col, NColsPlusBounds)] >= NMaxBurnSteps;
}
/* Return whether a given tree is on fire
@param row The row index of the tree
@param col The column index of the tree
@return Whether the tree in the given row and column is on fire
*/
bool IsOnFire(const int row, const int col) {
return Trees[TREE_MAP(row, col, NColsPlusBounds)] > 0 &&
!IsBurntOut(row, col);
}
/* For trees already burning, increment the number of time steps they have
burned
*/
void ContinueBurning() {
int row;
int col;
#pragma omp parallel for private(col)
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
if (IsOnFire(row, col)) {
NewTrees[NEW_TREE_MAP(row, col, NCols)] =
Trees[ TREE_MAP(row, col, NColsPlusBounds)] + 1;
}
}
}
}
/* Find trees that are not on fire yet and try to catch them on fire from
burning neighbor trees
*/
void BurnNew() {
int row;
int col;
#pragma omp parallel for private(col)
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
if (!IsOnFire(row, col) && !IsBurntOut(row, col)) {
/* Check neighbors */
/* Top */
if ((IsOnFire(row-1, col) ||
/* Left */
IsOnFire(row, col-1) ||
/* Bottom */
IsOnFire(row+1, col) ||
/* Right */
IsOnFire(row, col+1)) &&
/* Apply random chance */
(RandBetween(0, 100) < BurnProb)) {
/* Catch the tree on fire */
NewTrees[NEW_TREE_MAP(row, col, NCols)] = 1;
/* One thread at a time increments the burned tree count */
#pragma omp atomic
NBurnedTrees++;
}
}
}
}
}
/* Copy new tree data into old tree data */
void AdvanceTime() {
int row;
int col;
#pragma omp parallel for private(col)
for (row = 1; row < NRows + 1; row++) {
for (col = 1; col < NCols + 1; col++) {
Trees[ TREE_MAP(row, col, NColsPlusBounds)] =
NewTrees[NEW_TREE_MAP(row, col, NCols)];
}
}
}
/* Free allocated memory */
void FreeMemory() {
free(NewTrees);
free(Trees);
}
/* @param argc The number of command line arguments
@param argv String of command line arguments
*/
int main(int argc, char **argv) {
/* Set the program executable name */
strcpy(ExeName, argv[0]);
/* Allow the user to change simulation parameters via the command line */
GetUserOptions(argc, argv);
if (!AreParamsValid) {
/* Model parameters are not valid; exit early */
PrintUsageAndExit();
}
if (IsOutputtingEachStep) {
/* Open the output file */
OutputFile = fopen(OutputFilename, "w");
}
/* Do some calculations before splitting up the rows */
NTrees = NRows * NCols;
NRowsPlusBounds = NRows + 2;
NColsPlusBounds = NCols + 2;
NTreesPlusBounds = NRowsPlusBounds * NColsPlusBounds;
MiddleRow = NRows / 2;
MiddleCol = NCols / 2;
/* Allocate dynamic memory for the 1D tree arrays */
AllocateMemory();
/* Seed the random number generator */
srandom(RandSeed);
/* Initialize number of burned trees */
NBurnedTrees = 0;
/* Light a random tree on fire, set all other trees to be not burning */
InitData();
/* Start the simulation looping for the specified number of time steps */
for (CurStep = 0; CurStep < NSteps; CurStep++) {
if (IsOutputtingEachStep) {
/* Output tree data for the current time step */
OutputData();
}
/* For trees already burning, increment the number of time steps they have
burned */
ContinueBurning();
/* Find trees that are not on fire yet and try to catch them on fire from
burning neighbor trees */
BurnNew();
/* Copy new tree data into old tree data */
AdvanceTime();
}
/* Print the total percentage of trees burned */
printf("%.2f%% of the trees were burned\n",
(100.0 * NBurnedTrees) / NTrees);
if (IsOutputtingEachStep) {
/* Close the output file */
fclose(OutputFile);
}
/* Free allocated memory */
FreeMemory();
return 0;
}
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