Samuelhd em 22h08min de 3 de maio de 2022

2022-05-03T22:08:57Z

← Edição anterior		Edição das 22h08min de 3 de maio de 2022
Linha 26:		Linha 26:
	// Constants		// Constants

	const double k = 0~~.95~~;		const double k = 1.0;
	const double m = 1.05;		const double m = 1.0;
	const double alpha = 1.2;		const double alpha = 0.25;

	const double dt = 0.5;		const double dt = 0.01;
	const double tmax = ~~5500~~.0;		const double tmax = 11000.0;
			const int step = 10; // Number of iterations needed to save one "frame"
			const double start_reg = 9000.0; // Time before start saving the data

	const double length = 20.0;		const double length = 20.0;
Linha 44:		Linha 46:

	int i;		int i;
			int count = 0;
	double t = 0.0;		double t = 0.0;
	double pos, vel, *acc;		double pos, vel, *acc;
Linha 82:		Linha 85:

	// Save to file		// Save to file
	for (i=0; i<=N; i++) fprintf(file, "%f %f\n", length/N*i, pos[i]);		if (t >= start_reg && count >= step){
	fprintf(file, "\n\n");		for (i=0; i<=N; i++) fprintf(file, "%f %f\n", length/N*i, pos[i]);
			fprintf(file, "\n\n");
			count = 0;
			}
			else count++;


	// Update the current time		// Update the current time
	t += dt;		t += dt;

	}		}

Wallec em 21h11min de 30 de abril de 2022

2022-04-30T21:11:22Z

← Edição anterior		Edição das 21h11min de 30 de abril de 2022
Linha 1:		Linha 1:
			Para usar os scripts, o arquivo deve ser salvo como "fput.c".

	<source lang='c'>		<source lang='c'>
	// Libraries		// Libraries

Wallec: Criou página com ' // Libraries #include #include #include #include // Defines #define PI 3.14159265358979323846 // Prototypes d...'

2022-04-30T20:56:33Z

Criou página com '<source lang='c'> // Libraries #include <stdio.h> #include <stdlib.h> #include <math.h> #include <assert.h> // Defines #define PI 3.14159265358979323846 // Prototypes d...'

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<source lang='c'>
// Libraries

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>

// Defines

#define PI 3.14159265358979323846

// Prototypes

double *zero_array(int);
double *initial_condition(double, int);
double acceleration(double *, double, double, double);
double velocity(double, double, double, double);
double position(double, double, double, double);

// Constants

const double k = 0.95;
const double m = 1.05;
const double alpha = 1.2;

const double dt = 0.5;
const double tmax = 5500.0;

const double length = 20.0;
const int N = 32;

// Main

int main(){

// Variables

int i;
double t = 0.0;
double *pos, *vel, *acc;
double acc_new = 0.0;

// Output

FILE *file;
// char output[50];
char filename[] = "../data/output.dat";

// Generate inicial conditions for
pos = initial_condition(length, N); // position
vel = zero_array(N); // velocity
acc = zero_array(N); // acceleration

// Output file
// sprintf(output, filename);
// file = fopen(output, "w");
file = fopen(filename, "w");

// Time loop
while (t < tmax){

// Velocity verlet
for (i=1; i<N; i++){
pos[i] = position(pos[i], vel[i], acc[i], dt);
}

for (i=1; i<N; i++){
acc_new = acceleration((pos+i), k, m, alpha);
vel[i] = velocity(vel[i], acc[i], acc_new, dt);
acc[i] = acc_new;
}

// Save to file
for (i=0; i<=N; i++) fprintf(file, "%f %f\n", length/N*i, pos[i]);
fprintf(file, "\n\n");

// Update the current time
t += dt;
}

// Close the output file
fclose(file);

// Free the pointers
free(pos);
free(vel);
free(acc);

return 0;

}

// Functions

// Generate an array of zeros (double) with size N
double *zero_array(int N){
assert(N>0);
int i;
double *pointer;

// Calloc initializes every element with 0.0
pointer = (double *)calloc(N, sizeof(double));

if (pointer != NULL){
return(pointer);
}
else {
fprintf(stderr,"Error in routine zero_array\n");
exit(8);
}
}

// Generate an array with the initial condition determined by the FPUT original problem, N elements with x values ranged from 0 to length.
double *initial_condition(double length, int N){
assert(N>0);
int i;
double *pointer;
double step = length/N;

pointer = (double *)calloc(N, sizeof(double));

if (pointer != NULL){
for (i=0; i<=N; ++i) *(pointer+i) = sin(PI*(step*i)/length);
return(pointer);
}
else {
fprintf(stderr,"Error in routine initial_condition\n");
exit(8);
}
}

// Velocity-Verlet method

// Updates the acceleration
double acceleration(double *pos, double k, double m, double alpha){
return k/m * (pos[1] + pos[-1] - 2*pos[0]) * (1.0 + alpha * (pos[1] - pos[-1]));
}

// Updates the velocity
double velocity(double vel_old, double acc, double acc_new, double dt){
return vel_old + 0.5*(acc+acc_new)*dt;
}

// Updates the position
double position(double pos_old, double vel, double acc, double dt){
return pos_old + vel*dt + 0.5*acc*dt*dt;
}
</source>

Programa - Histórico de revisão

Samuelhd em 22h08min de 3 de maio de 2022

Wallec em 21h11min de 30 de abril de 2022

Wallec: Criou página com ' // Libraries #include #include #include #include // Defines #define PI 3.14159265358979323846 // Prototypes d...'