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/*
* utils.c
*
* Utility stuff
*
* (c) 2007-2008 Thomas White <taw27@cam.ac.uk>
*
* dtr - Diffraction Tomography Reconstruction
*
*/
#include <math.h>
#include <gsl/gsl_matrix.h>
#include <string.h>
#include "utils.h"
/* Return the MOST POSITIVE of two numbers */
unsigned int biggest(signed int a, signed int b) {
if ( a>b ) {
return a;
}
return b;
}
/* Return the LEAST POSITIVE of two numbers */
unsigned int smallest(signed int a, signed int b) {
if ( a<b ) {
return a;
}
return b;
}
double distance(double x1, double y1, double x2, double y2) {
return sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));
}
double modulus(double x, double y, double z) {
return sqrt(x*x + y*y + z*z);
}
double distance3d(double x1, double y1, double z1, double x2, double y2, double z2) {
return modulus(x1-x2, y1-y2, z1-z2);
}
/* Angle between two vectors. Answer in radians */
double angle_between(double x1, double y1, double z1, double x2, double y2, double z2) {
double mod1 = modulus(x1, y1, z1);
double mod2 = modulus(x2, y2, z2);
return acos( (x1*x2 + y1*y2 + z1*z2) / (mod1*mod2) );
}
/* As above, answer in degrees */
double angle_between_d(double x1, double y1, double z1, double x2, double y2, double z2) {
return rad2deg(angle_between(x1, y1, z1, x2, y2, z2));
}
/* Wavelength of an electron (in m) given accelerating potential (in V) */
double lambda(double V) {
double m = 9.110E-31;
double h = 6.625E-34;
double e = 1.60E-19;
double c = 2.998E8;
return h / sqrt(2*m*e*V*(1+((e*V) / (2*m*c*c))));
}
size_t skipspace(const char *s) {
size_t i;
for ( i=0; i<strlen(s); i++ ) {
if ( (s[i] != ' ') && (s[i] != '\t') ) return i;
}
return strlen(s);
}
void chomp(char *s) {
size_t i;
if ( !s ) return;
for ( i=0; i<strlen(s); i++ ) {
if ( (s[i] == '\n') || (s[i] == '\r') ) {
s[i] = '\0';
return;
}
}
}
void matrix_vector_show(const gsl_matrix *m, const gsl_vector *v, const char *prefix) {
int i, j;
if ( prefix == NULL ) prefix = "";
for ( i=0; i<m->size1; i++ ) {
printf("%s[ ", prefix);
for ( j=0; j<m->size2; j++ ) {
printf("%12.8f ", gsl_matrix_get(m, i, j));
}
printf(" ] [ q%i ] = [ %15.2f ]\n", i+1, gsl_vector_get(v, i));
}
}
int sign(double a) {
if ( a < 0 ) return -1;
if ( a > 0 ) return +1;
return 0;
}
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