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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int generateSinus(double * sinus,
int nbPts,
double physicalRange,
double amplitudeFactor,
double yOffset);
int generateLinear(double * linear,
int nbPts,
double physicalRange,
double a,
double b);
int save2Ddata_dbl(char const * filename, double * data, int nbPts, double physicalRange);
int substractBdataFromAdata(const double * a,
const double * b,
int nbPts,
double * res);
/**
* Program entry point
*/
int main(void) {
static const double CST_PI = 4 * atan (1.0);
int nbPoints = 1000;
double * sinusoide = NULL;
double * linear = NULL;
double * sinMinuslinear = NULL;
sinusoide = malloc(nbPoints*sizeof(*sinusoide));
if (!sinusoide) {
fprintf(stderr, "Allocation failure. Exiting...\n");
exit(EXIT_FAILURE);
}
generateSinus(sinusoide, nbPoints, 4*CST_PI, 1.0, -0.5);
save2Ddata_dbl("sinus.txt", sinusoide, nbPoints, 4*CST_PI);
linear = malloc(nbPoints*sizeof(*linear));
if (!linear) {
fprintf(stderr, "Allocation failure. Exiting...\n");
free(sinusoide);
exit(EXIT_FAILURE);
}
generateLinear(linear, nbPoints, 4*CST_PI, 0.25, -1.0);
save2Ddata_dbl("linear.txt", linear, nbPoints, 4*CST_PI);
sinMinuslinear = malloc(nbPoints*sizeof(*sinMinuslinear));
if (!sinMinuslinear) {
fprintf(stderr, "Allocation failure. Exiting...\n");
free(sinusoide); free(linear);
exit(EXIT_FAILURE);
}
substractBdataFromAdata(sinusoide, linear, nbPoints, sinMinuslinear);
save2Ddata_dbl("diffSinusLinear.txt", sinMinuslinear, nbPoints, 4*CST_PI);
free(linear);
free(sinusoide);
free(sinMinuslinear);
return 0;
}
/**
* Generate a sinus
*/
int generateSinus(double * sinus,
int nbPts,
double physicalRange,
double amplitudeFactor,
double yOffset) {
int rc = -1;
if (sinus && nbPts > 0) {
double step = physicalRange / nbPts;
double physicalValue = 0.0;
int i;
for (i=0; i<nbPts; ++i, physicalValue+=step) {
sinus[i] = ( amplitudeFactor * sin(physicalValue) ) + yOffset;
}
rc = 0;
}
return rc;
}
/**
* Generate a line (ax+ b)
*/
int generateLinear(double * linear,
int nbPts,
double physicalRange,
double a,
double b) {
int rc = -1;
if (linear && nbPts > 0) {
double step = physicalRange / nbPts;
double physicalValue = 0.0;
int i;
for (i=0; i<nbPts; ++i, physicalValue+=step) {
linear[i] = a*physicalValue + b;
}
rc = 0;
}
return rc;
}
/**
* Substract b data from a data (result stored in res)
*/
int substractBdataFromAdata(const double * a,
const double * b,
int nbPts,
double * res) {
int rc = -1;
if (a && b && res && nbPts > 0) {
int i;
for (i=0; i<nbPts; ++i) {
res[i] = a[i] - b[i];
}
rc = 0;
}
return rc;
}
/**
* Save data to a text file (usable with gnuplot)
*/
int save2Ddata_dbl(char const * filename, double * data, int nbPts, double physicalRange) {
int rc = -1;
if (filename) {
FILE * f = fopen(filename, "w");
if (f) {
int i;
double step = physicalRange / nbPts;
double physicalValue = 0.0;
char buff[50]= {0};
for (i=0; i<nbPts; ++i, physicalValue+=step) {
sprintf(buff, "%lf %lf\n", physicalValue, data[i]);
fputs(buff, f);
}
fclose(f);
rc = 0;
}
else {
fprintf(stderr, "Failed to open %s for writing\n", filename);
}
}
return rc;
} |