I am writing a Game of Life code and that simulation will run for 1000 timesteps. The program seems to be running well, but I want to add another feature where the timesteps will be printed out on top of the current state of the board. For example, on timestep = 0, the initial board will be printed out and on timestep = 1000 the final state of the board will be printed out.
I have thought of the following code to print out the timestep (note: I am still a beginner at learning C programming):
int timestep = 1000;
printf("Timestep: ");
for (int init_time = 0; init_time < timestep; init_time++)
{
printf("%d", init_time);
}
I am not sure whether this code will print out this way: Timestep Sample Image (Click Here)
I am thinking that a row needs to be cleared out to print out the timestep, but I am not sure how to do that or if this is even the correct approach to solving that issue. I will appreciate any kind of help that you can offer.
Related
I'm working to parallelise a disease spread model in c using OpenMP but am only seeing massive (order of magnitude) slowdown. I'll point out at the outset that I am a complete novice with both OpenMP and c.
The code loops over every point in the simulation and checks its status (susceptible, infected, recovered) and for each status, follows an algorithm to determine its status at the next time step.
I'll give the loop for infected points for illustrative purposes. Lpoints is a list of indices for points in the simulation, Nneigh gives the number of neighbours each point has and Lneigh gives the indices of these neighbours.
for (ipoint=0;ipoint<Nland;ipoint++) { //loop over all points
if (Lpoints_old[ipoint]==I) { //act on infected points
/* Probability Prec of infected population recovering */
xi = genrand();
if (xi<Pvac) { /* This point recovers (I->R) */
Lpoints[ipoint] = R;
/* printf("Point %d gained immunity\n",ipoint); */
}
else {
/* Probability of being blockaded by neighbours */
nsn = 0;
for (in=0;in<Nneigh[ipoint];in++) { /*count susceptible neighbours (nsn)*/
//if (npoint<0) printf("Bad npoint 1: %d in=%d\n",ipoint,in);
//fflush(stdout);
npoint = Lneigh[ipoint][in];
if (Lpoints_old[npoint]==S) nsn++;
}
Prob = (double)nsn*Pblo;
xi = genrand();
if (xi<Prob) { /* The population point is blockaded (I->R)*/
Lpoints[ipoint] = R;
}
else { /* Still infected */
Lpoints[ipoint] = I;
}
} /*else*/
} /*infected*/
} /*for*/
I tried to parallelise by adding #pragma omp parallel for default(shared) private(ipoint,xi,in,npoint,nsn,Prob) before the for loop. (I tried using default(none) as is generally recommended but it wouldn't compile.) On the small grid I am using to test the original series code runs in about 5 seconds and the OpenMP version runs in around 50.
I have searched for ages online and every similar problem seems to be the result of false cache sharing and has been solved by using static scheduling with a chunk size divisible by 8. I tried varying the chunk size to no effect whatsoever, only getting the timings to the original order when the chunk size surpassed the size of the problem (i.e. back to linearly carrying out on one thread.)
Slowdown doesn't seem any better when the problem is more appropriately scaled as far as I can tell either. I have no idea why this isn't working and what's going wrong. Any help greatly appreciated.
I have a question that may be hard to understand -- but I will try my best to explain.
I'm programming the Simon Game in C. This implementation specifically read/writes to a hardware DAQ module that has a 4 LED display, and 4 corresponding toggle switches.
As per the rules of the Game, I've seeded and generated a random sequence of numbers between 0 and 3 (sequence length is arbitrarily 5). In the Game, if the player presses the wrong switch (i.e. blue is shown but you press green), the game ends and restarts.
The way I've set up the Game looks like this:
(I haven't included the code for function "blinkLED" here -- it turns the actual LED on/off.)
void runSimon(void){
int sequence[MAX_SEQ_LEN];
int i;
int count = 0;
// Seeds the random number generator.
srand((unsigned)time(NULL));
// Generate the random LED sequence & store it as an array.
for (i = 0; i < MAX_SEQ_LEN; i++){
sequence[i] = (rand() % NUM_LEDS);
}
// The game begins!
while (continueSuperLoop() == TRUE){
// Loop the game while the sequence length is less than the pre-defined maximum (currently it's 5).
while (count < MAX_SEQ_LEN){
for (i = 0; i <= count; i++){
// Blink the first 'count' LEDs in the sequence, one at a time.
blinkLED(sequence[i], 1, ONE_SEC);
//
//
//THE ISSUE SHOULD BE HERE (!)
//
// Monitors whether or not the player has made a mistake...if so, blink the red LED thrice, then restart the game.
if (digitalRead(sequence[ !i ] == SWITCH_ON)){
blinkLED(LED_1_R, 3, HALF_SEC);
Sleep(3 * ONE_SEC);
continue;
}
// Monitors whether or not the correct switch is being pressed -- waits for it to be released
while (digitalRead(sequence[i]) == SWITCH_ON){}
}
count++;
}
// If 'count' is equal to 'MAX_SEQ_LEN', the green LED blinks 3x to indicate the player has won .
if (count == MAX_SEQ_LEN){
blinkLED(LED_0_G, 3, HALF_SEC);
Sleep(3 * ONE_SEC);
}
}
}
Where I indicated an issue, I'm not sure how the "digitalRead(sequence[ ! i ]" behaves; I need this line to read every switch that's not supposed to be pressed.
I don't think the compiler understands what I'm trying to do here, though -- for example, if the first number in the sequence is 3 (representing the 4th LED), I need to specify that every other number (0, 1, 2) and its corresponding switch should not be pressed.
Would a solution be to store the current number in the sequence, having a set of four TRUE/FALSE flags for each LED, and monitoring the three non-current numbers and their corresp. switches to see if they are pressed?
I'm getting quite frustrated with writing this program. I'm pretty new to programming. Any help is appreciated.
I'm not sure I understand the rules of this game correctly but one thing that jumps out instantly is
digitalRead(sequence[ !i ]
I think you want
!digitalRead(sequence[ i ]
Also, you need to fix your game flow. Right now it's:
1. Light LED.
2. Check if user pressed the right button.
You need to wait for some time before checking a switch or wait for ANY switch to be pressed and see if it's the correct one. So something like this:
1. Light LED.
2. Wait for timeout or ANY switch to be pressed.
3. If timeout: error
4. else: check if switch that was pressed is correct.
In C, ! operator is a unary NOT. When applied to an integer i, it is equivalent to if (i == 0) return 1; else return 0;. Then you are using !i as an index for sequence array, so it will be either sequence[0] or sequence[1], and clearly this is not what you want. Also your == is inside of digitalRead call :)
I would suggest explicitly checking for every other button not to be pressed. Like this:
int isOtherPressed = 0;
for (ledId = 0; ledId < NUM_LEDS; ledId++) {
if (ledId != sequence[i] && digitalRead(ledId) == SWITCH_ON) {
isOtherPressed = 1;
}
}
if (isOtherPressed) {
// restart the game
}
However, I'm suspicious about the whole gameplay you have, but maybe it's just because I don't know how digitalRead works. For example, the way you use continue doesn't seem to stop the game. Maybe you meant break?
Hey guys I have created a program in C that tests all numbers between 1 and 10000 to check if they are perfect using a function that determines whether a number is perfect. Once it finds these it prints them to the user, they are 6, 28, 496 and 8128. After this the program then prints out all the factors of each perfect number to the user. This is all fine. Here is my problem.
The final part of my task asks me to:
"Use a "twirly" to indicate that your program is happily working away. A "twirly" is the following characters printed over the top of each other in the following order: '|' '/' '-' '\'. This has the effect of producing a spinning wheel - ie a "twirly". Hint: to do this you can use \r (instead of \n) in printf to give a carriage return only (instead of a carriage return linefeed). (Note: this may not work on some systems - you do not have to do it this way.)"
I have no idea what a twirly is or how to implement one. My tutor said it has something to do with the sleep and delay functions which I also don't know how to use. Can anyone help me with this last stage, it sucks that all my coding is complete but I can't get this "twirly" thing to work.
if you want to simultaneously perform the task of
Testing the numbers and
Display the twirly on screen
while the process goes on then you better look into using threads. using POSIX threads you can initiate the task on a thread and the other thread will display the twirly to the user on terminal.
#include<stdlib.h>
#include<pthread.h>
int Test();
void Display();
int main(){
// create threads each for both tasks test and Display
//call threads
//wait for Test thread to finish
//terminate display thread after Test thread completes
//exit code
}
Refer chapter 12 for threads
beginning linux programming ebook
Given the program upon which the user is "waiting", I believe the problem as stated and the solutions using sleep() or threads are misguided.
To produce all the perfect numbers below 10,000 using C on a modern personal computer takes about 1/10 of a second. So any device to show the computer is "happily working away" would either never be seen or would significanly intefere with the time it takes to get the job done.
But let's make a working twirly for perfect number search anyway. I've left off printing the factors to keep this simple. Since 10,000 is too low to see the twirly in action, I've upped the limit to 100,000:
#include <stdio.h>
#include <string.h>
int main()
{
const char *twirly = "|/-\\";
for (unsigned x = 1; x <= 100000; x++)
{
unsigned sum = 0;
for (unsigned i = 1; i <= x / 2; i++)
{
if (x % i == 0)
{
sum += i;
}
}
if (sum == x)
{
printf("%d\n", x);
}
printf("%c\r", twirly[x / 2500 % strlen(twirly)]);
}
return 0;
}
No need for sleep() or threads, just key it into the complexity of the problem itself and have it update at reasonable intervals.
Now here's the catch, although the above works, the user will never see a fifth perfect number pop out with a 100,000 limit and even with a 100,000,000 limit, which should produce one more, they'll likely give up as this is a bad (slow) algorithm for finding them. But they'll have a twirly to watch.
i as integer
loop i: 1 to 10000
loop j: 1 to i/2
sum as integer
set sum = 0
if i%j == 0
sum+=j
return sum==i
if i%100 == 0
str as character pointer
set *str = "|/-\\"
set length = 4
print str[p] using "%c\r" as format specifier
Increment p and assign its modulo by len to p
I'm developing a plugin in C that detects audio peaks using gstreamer-1.0. I don't really have any knowledge about audio programming and so far, my plugin can only detect sound impulsion (if there is no audio, nothing happens, if there is sound, I print the energy).
Here is the sample code of my (really simple) algorithm.
gfloat energy_of_sample(guint8 array[], int num_elements, gfloat *p)
{
gfloat energy=0.f;
for(int i=0 ; i<num_elements ; i++)
{
energy += array[i]*array[i]/4096;
if (*p < (array[i]*array[i]/4096)) *p = array[i]*array[i]/4096;
}
return energy/num_elements;
}
static void
audio_process(GstBPMdetect *filter, GstBuffer *music)
{
GstMapInfo info;
gint threshold = 6;
// gets the information of the buffer and put it in "info"
gst_buffer_map (music, &info, GST_MAP_READ);
// calculate the average of the buffer data
gfloat energy = 0;
gfloat peak = 0;
energy = energy_of_sample(info.data, info.size, &peak);
if (energy >= threshold )g_print("energy : %f , peak : %f \n", energy,peak);
}
If the audio source is, for exemple, a simple hand clap or kick drum only, my plugin detects the audio peak just fine. But when the audio source is a song, my plugin is constantly detecting sound impulsion (always over the threshold).
My solution for that issue was to add a low-pass filter so only bass sound would be detected. By doing that, I'm cutting every part of the song containing high frequencies only and this is not what I want (will not work for high frequency beats).
So my question is : Does anyone have an idea on how to detect beats (audio impulsion) without cutting the high frequencies ? Tanks to everyone and hope that my question is clear !
You should measure energy not peak. There is a great method to calculate energy. Use variance formula from statistics. You need count square of sum and sum of squares for all points within an interval of 20 - 50 milliseconds. Using the variance formula you get the energy. The formula is here
http://staff.icdi.wvu.edu/djhstats/variance1.JPG
As an alternative you may use the existing plugin level in the set of good plugins.
We all know how to draw a line in Processing.
But when we draw a line, the line is shown immediately.
What if i want to witness the drawing process, namely, to see the line moving forward, gradually completes a whole line.
Here's what i want to realize: to DRAW several lines and curves which finally turn into some pattern.
So how to make that happen? Using array?
Many thanks.
In processing all of the drawing happens in a loop. An easy way to create animated sequences like you describe is to use frameCount to drive it and using the modulus function % is a good way to create a loop. For example, to animate along the x axis:
void draw() {
float x = 50;
float y = 50;
float lineLength = 50;
int framesToAnimate = 60;
line(x,y,x+float(frameCount % framesToAnimate)/framesToAnimate*lineLength, y);
}
Note: strange things will happen if you don't cast / convert to a float
I use this pretty often to animate other features such as the color.
fill(color(127 + sin(float(frameCount)/90)*127, 0, 0, 127));
If you want to get more advanced, setting vectors and coordinates with PVector. There is a pretty good tutorial on Daniel Shiffman's site.
If you want to set your animation independent of frame rate, you can use mills() instead. That will return current time since the sketch started so you can set something to happen in a given time in seconds.
like for example:
long initialTime;
void setup(){
size(400,200);
initialTime = millis();
}
void draw() {
float x = 50;
float y = 50; //set the multiplier to adjust speed
line(x,y,x+(millis()-initialTime)*0.01, y); //10 px/sec
line(x,y+50,x+(millis()-initialTime)*0.05, y+50); //50 px/sec
line(x,y+100,x+(millis()-initialTime)*0.001, y+100); // 1 px/sec
}
There is also some animation libraries, i've seen some impressive results with some, but i never used them. Here a list.