/* See r4.h. */
/* Last edited on 2021-06-09 20:43:57 by jstolfi */

#define _GNU_SOURCE
#include <stdio.h>
#include <stdint.h>
#include <math.h>

#include <r4.h>

#include <jsrandom.h>
#include <affirm.h>
#include <rn.h>
#include <vec.h>

#define N 4

void r4_zero (r4_t *r)
  { r->c[0] = 0.0;
    r->c[1] = 0.0;
    r->c[2] = 0.0;
    r->c[3] = 0.0;
  }

void r4_all (double x, r4_t *r)
  { r->c[0] = x;
    r->c[1] = x;
    r->c[2] = x;
    r->c[3] = x;
  }

void r4_axis (int32_t i, r4_t *r)
  { affirm((i >= 0) && (i < N), "r4_axis: bad index");
    r->c[0] = 0.0;
    r->c[1] = 0.0;
    r->c[2] = 0.0;
    r->c[3] = 0.0;

    r->c[i] = 1.0;
  }

void r4_add (r4_t *a, r4_t *b, r4_t *r)
  { r->c[0] = a->c[0] + b->c[0];
    r->c[1] = a->c[1] + b->c[1];
    r->c[2] = a->c[2] + b->c[2];
    r->c[3] = a->c[3] + b->c[3];
  }

void r4_sub (r4_t *a, r4_t *b, r4_t *r)
  { r->c[0] = a->c[0] - b->c[0];
    r->c[1] = a->c[1] - b->c[1];
    r->c[2] = a->c[2] - b->c[2];
    r->c[3] = a->c[3] - b->c[3];
  }

void r4_neg (r4_t *a, r4_t *r)
  { r->c[0] = - a->c[0];
    r->c[1] = - a->c[1];
    r->c[2] = - a->c[2];
    r->c[3] = - a->c[3];
  }

void r4_scale (double s, r4_t *a, r4_t *r)
  { r->c[0] = s * a->c[0];
    r->c[1] = s * a->c[1];
    r->c[2] = s * a->c[2];
    r->c[3] = s * a->c[3];
  }

void r4_mix (double s, r4_t *a, double t, r4_t *b, r4_t *r)
  { r->c[0] = s * a->c[0] + t * b->c[0];
    r->c[1] = s * a->c[1] + t * b->c[1];
    r->c[2] = s * a->c[2] + t * b->c[2];
    r->c[3] = s * a->c[3] + t * b->c[3];
  }

void r4_mix_in (double s, r4_t *a, r4_t *r)
  { r->c[0] += s * a->c[0];
    r->c[1] += s * a->c[1];
    r->c[2] += s * a->c[2];
    r->c[3] += s * a->c[3];
  }

void r4_weigh (r4_t *a, r4_t *w, r4_t *r)
  { r->c[0] = a->c[0] * w->c[0];
    r->c[1] = a->c[1] * w->c[1];
    r->c[2] = a->c[2] * w->c[2];
    r->c[3] = a->c[3] * w->c[3];
  }

double r4_norm (r4_t *a)
  { double a0 = a->c[0];
    double a1 = a->c[1];
    double a2 = a->c[2];
    double a3 = a->c[3];
    return sqrt(a0*a0 + a1*a1 + a2*a2 + a3*a3);
  }

double r4_norm_sqr (r4_t *a)
  { double a0 = a->c[0];
    double a1 = a->c[1];
    double a2 = a->c[2];
    double a3 = a->c[3];
    return a0*a0 + a1*a1 + a2*a2 + a3*a3;
  }

double r4_L_inf_norm (r4_t *a)
  { double d = 0.0;
    double a0 = fabs(a->c[0]);
    double a1 = fabs(a->c[1]);
    double a2 = fabs(a->c[2]);
    double a3 = fabs(a->c[3]);
    if (a0 > d) d = a0;
    if (a1 > d) d = a1;
    if (a2 > d) d = a2;
    if (a3 > d) d = a3;
    return (d);
  }

double r4_dist (r4_t *a, r4_t *b)
  { double d0 = (a->c[0] - b->c[0]);
    double d1 = (a->c[1] - b->c[1]);
    double d2 = (a->c[2] - b->c[2]);
    double d3 = (a->c[3] - b->c[3]);
    double d = sqrt(d0*d0 + d1*d1 + d2*d2 + d3*d3);
    return (d);
  }

double r4_dist_sqr (r4_t *a, r4_t *b)
  { double d0 = (a->c[0] - b->c[0]);
    double d1 = (a->c[1] - b->c[1]);
    double d2 = (a->c[2] - b->c[2]);
    double d3 = (a->c[3] - b->c[3]);
    return d0*d0 + d1*d1 + d2*d2 + d3*d3;
  }

double r4_L_inf_dist (r4_t *a, r4_t *b)
  { double d = 0.0;
    double d0 = fabs(a->c[0] - b->c[0]);
    double d1 = fabs(a->c[1] - b->c[1]);
    double d2 = fabs(a->c[2] - b->c[2]);
    double d3 = fabs(a->c[3] - b->c[3]);
    if (d0 > d) d = d0;
    if (d1 > d) d = d1;
    if (d2 > d) d = d2;
    if (d3 > d) d = d3;
    return (d);
  }

double r4_dir (r4_t *a, r4_t *r)
  { double d = sqrt
      ( a->c[0]*a->c[0] + 
        a->c[1]*a->c[1] + 
        a->c[2]*a->c[2] + 
        a->c[3]*a->c[3]
      );
    r->c[0] = a->c[0]/d;
    r->c[1] = a->c[1]/d;
    r->c[2] = a->c[2]/d;
    r->c[3] = a->c[3]/d;
    return (d);
  }

double r4_L_inf_dir (r4_t *a, r4_t *r)
  { double d = 0.0;
    double a0 = fabs(a->c[0]);
    double a1 = fabs(a->c[1]);
    double a2 = fabs(a->c[2]);
    double a3 = fabs(a->c[3]);
    if (a0 > d) d = a0;
    if (a1 > d) d = a1;
    if (a2 > d) d = a2;
    if (a3 > d) d = a3;
    r->c[0] = a->c[0]/d;
    r->c[1] = a->c[1]/d;
    r->c[2] = a->c[2]/d;
    r->c[3] = a->c[3]/d;
    return (d);
  }

double r4_dot (r4_t *a, r4_t *b)
  { return a->c[0]*b->c[0] + a->c[1]*b->c[1] + a->c[2]*b->c[2] + a->c[3]*b->c[3]; }

double r4_cos (r4_t *a, r4_t *b)
  { double a0 = a->c[0];
    double a1 = a->c[1];
    double a2 = a->c[2];
    double a3 = a->c[3];

    double b0 = b->c[0];
    double b1 = b->c[1];
    double b2 = b->c[2];
    double b3 = b->c[3];

    double ab = a0*b0 + a1*b1 + a2*b2 + a3*b3;
    double aa = a0*a0 + a1*a1 + a2*a2 + a3*a3;
    double bb = b0*b0 + b1*b1 + b2*b2 + b3*b3;
    return ab/(sqrt(aa)*sqrt(bb));
  }

double r4_sin (r4_t *a, r4_t *b)
  { return rn_sin(N, &(a->c[0]), &(b->c[0])); }

double r4_angle (r4_t *a, r4_t *b)
  { return rn_angle(N, &(a->c[0]), &(b->c[0])); }

void r4_cross (r4_t *a, r4_t *b, r4_t *c, r4_t *r)
  { double d01 = a->c[0]*b->c[1] - a->c[1]*b->c[0];
    double d02 = a->c[0]*b->c[2] - a->c[2]*b->c[0];
    double d12 = a->c[1]*b->c[2] - a->c[2]*b->c[1];
    double d03 = a->c[0]*b->c[3] - a->c[3]*b->c[0];
    double d13 = a->c[1]*b->c[3] - a->c[3]*b->c[1];
    double d23 = a->c[2]*b->c[3] - a->c[3]*b->c[2];

    r->c[0] = - d12*c->c[3] + d13*c->c[2] - d23*c->c[1];
    r->c[1] =   d02*c->c[3] - d03*c->c[2] + d23*c->c[0];
    r->c[2] = - d01*c->c[3] + d03*c->c[1] - d13*c->c[0];
    r->c[3] =   d01*c->c[2] - d02*c->c[1] + d12*c->c[0];
  }

double r4_det (r4_t *a, r4_t *b, r4_t *c, r4_t *d)
  { r4_t p;
    r4_cross(a, b, c, &p);
    return p.c[0]*d->c[0] + p.c[1]*d->c[1] + p.c[2]*d->c[2] + p.c[3]*d->c[3];
  }

double r4_decomp (r4_t *a, r4_t *u, r4_t *para, r4_t *perp)
  { double *paran = (para == NULL ? NULL : &(para->c[0]));
    double *perpn = (perp == NULL ? NULL : &(perp->c[0]));
    return rn_decomp(N, &(a->c[0]), &(u->c[0]), paran, perpn);
  }

int32_t r4_is_finite(r4_t *p)
  { if (fabs(p->c[0]) == INF) return FALSE;
    if (fabs(p->c[1]) == INF) return FALSE;
    if (fabs(p->c[2]) == INF) return FALSE;
    if (fabs(p->c[3]) == INF) return FALSE;
    return TRUE;
  }

bool_t r4_eq(r4_t *p, r4_t *q)
  { if (p->c[0] != q->c[0]) return FALSE;
    if (p->c[1] != q->c[1]) return FALSE;
    if (p->c[2] != q->c[2]) return FALSE;
    if (p->c[3] != q->c[3]) return FALSE;
    return TRUE;
  }

void r4_throw_cube (r4_t *r)
  { int32_t i;
    for (i = 0; i < N; i++)
      { r->c[i] = 2.0 * drandom() - 1.0; }
  }

void r4_throw_dir (r4_t *r)
  { /* Generate a nonzero Gaussian random vector: */
    int32_t i;
    double r2;
    do
      { r4_throw_normal(r);
        /* Discard if too close to origin: */
        r2 = 0.0;
        for (i = 0; i < N; i++) { double ci = r->c[i]; r2 += ci*ci; }
      }
    while (r2 < 1.0e-20);
    /* Normalize to unit length: */
    double m = sqrt(r2);
    for (i = 0; i < N; i++) { r->c[i] /= m; }
  }

void r4_throw_ball (r4_t *r)
  { rn_throw_ball(N, &(r->c[0])); }

void r4_throw_normal (r4_t *r)
  { int32_t i;
    for (i = 0; i < N; i++)
      { r->c[i] = dgaussrand(); }
  }

void r4_print (FILE *f, r4_t *a)
  { r4_gen_print(f, a, NULL, NULL, NULL, NULL); }

void r4_gen_print (FILE *f, r4_t *a, char *fmt, char *lp, char *sep, char *rp)
  { rn_gen_print(f, N, &(a->c[0]), fmt, lp, sep, rp); }

vec_typeimpl(r4_vec_t,r4_vec,r4_t);