vector3D.h

/* This code is part of N-Bodies Problem
 *
 * N-Bodies Problem is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Copyright (C) Bruno Jiménez, 2011
 */

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

#define VECTOR3D

struct vector3D
{
    long double x,y,z;
}; 

/* We pass a pointer to a vector to get it from
 * keyboard                                     */
void get_vector(struct vector3D *v)
{
    printf("Imput the x component of the vector\n");
    scanf("%Lf",&v->x);
    printf("Imput the y component of the vector\n");
    scanf("%Lf",&v->y);
    printf("Imput the z component of the vector\n");
    scanf("%Lf",&v->z);
}

/* Prints out a vector with the format
 * (1st component,<TAB>2nd component,<TAB>3rd component) */
void print_vector(struct vector3D v)
{
    printf("(%Lf,\t%Lf,\t%Lf)\n",v.x,v.y,v.z);
}

/*const char *to_string(struct vector3D v)
{
    return "("+v.x+",\t"+v.y+",\t"+v.z+")"; //problemas al pasar un double a char *
}*/

/* Returns a vector which is the sume of two */
struct vector3D suma(struct vector3D v,struct vector3D w)
{
    return (struct vector3D) {v.x+w.x,v.y+w.y,v.z+w.z};
}

/* Returns the vector which is the adition of the first
 * and the negative of the second                       */
struct vector3D resta(struct vector3D v,struct vector3D w)
{
    return suma(v,(struct vector3D){-w.x,-w.y,-w.z});
}

/* Returns the vector multiplied by an scalar */
struct vector3D multiply_vector_by(struct vector3D v, double n)
{
    return (struct vector3D) {v.x*n,v.y*n,v.z*n};
}

/* Returns the length of the vector */
long double module(struct vector3D v)
{
    return sqrt(v.x*v.x+v.y*v.y+v.z*v.z);
}

/* Returns the distance between two vectors as if the
 * origin of both were at (0,0,0)                     */
long double distancia(struct vector3D v,struct vector3D w)
{
    return module(resta(v,w));
}

/* Returns the scalar or inner product of two vectors */
long double scalar_product(struct vector3D v,struct vector3D w)
{
    return v.x*w.x+v.y*w.y+v.z*w.z;
}

/* Returns the vector which is the vectorial product
 * of two vectors */
struct vector3D vectorial_product(struct vector3D v,struct vector3D w)
{
    return (struct vector3D){v.y*w.z-w.y*v.z,v.z*w.x-v.x*w.z,v.x*w.y-v.y*w.x};
}