Exemple #1
0
void mpfr_taylor_sin_bounded(mpfr_t R, mpfr_t x, unsigned int N)
{
	mpfr_printf("%.20RNF\n", x);
	assert(mpfr_cmp_ui(x, 0) >= 0 && mpfr_cmp(x, MPFR_HALF_PI) <= 0);
	mpfr_t t, x_2;
	
	mpfr_init_set(R, x, MPFR_RNDN);
	mpfr_init_set(t, x, MPFR_RNDN);
	mpfr_init(x_2);
	mpfr_mul(x_2, x, x, MPFR_RNDN);

	for(int n = 1; n < N; n++)
	{
		mpfr_div_ui(t, t, (2*n+1)*(2*(n++)), MPFR_RNDN);
		mpfr_mul(t, t, x_2, MPFR_RNDN);
		mpfr_sub(R, R, t, MPFR_RNDN);
		mpfr_div_ui(t, t, (2*n+1)*(2*n), MPFR_RNDN);
		mpfr_mul(t, t, x_2, MPFR_RNDN);
		mpfr_add(R, R, t, MPFR_RNDN);
	}
}
Exemple #2
0
/* With pow.c r5497, the following test fails on a 64-bit Linux machine
 * due to a double-rounding problem when rescaling the result:
 *   Error with underflow_up2 and extended exponent range
 *   x = 7.fffffffffffffff0@-1,
 *   y = 4611686018427387904, MPFR_RNDN
 *   Expected 1.0000000000000000@-1152921504606846976, inex = 1, flags = 9
 *   Got      0, inex = -1, flags = 9
 * With pow_ui.c r5423, the following test fails on a 64-bit Linux machine
 * as underflows and overflows are not handled correctly (the approximation
 * error is ignored):
 *   Error with mpfr_pow_ui, flags cleared
 *   x = 7.fffffffffffffff0@-1,
 *   y = 4611686018427387904, MPFR_RNDN
 *   Expected 1.0000000000000000@-1152921504606846976, inex = 1, flags = 9
 *   Got      0, inex = -1, flags = 9
 */
static void
underflow_up2 (void)
{
  mpfr_t x, y, z, z0, eps;
  mpfr_exp_t n;
  int inex;
  int rnd;

  n = 1 - mpfr_get_emin ();
  MPFR_ASSERTN (n > 1);
  if (n > ULONG_MAX)
    return;

  mpfr_init2 (eps, 2);
  mpfr_set_ui_2exp (eps, 1, -1, MPFR_RNDN);  /* 1/2 */
  mpfr_div_ui (eps, eps, n, MPFR_RNDZ);      /* 1/(2n) rounded toward zero */

  mpfr_init2 (x, sizeof (unsigned long) * CHAR_BIT + 1);
  inex = mpfr_ui_sub (x, 1, eps, MPFR_RNDN);
  MPFR_ASSERTN (inex == 0);  /* since n < 2^(size_of_long_in_bits) */
  inex = mpfr_div_2ui (x, x, 1, MPFR_RNDN);  /* 1/2 - eps/2 exactly */
  MPFR_ASSERTN (inex == 0);

  mpfr_init2 (y, sizeof (unsigned long) * CHAR_BIT);
  inex = mpfr_set_ui (y, n, MPFR_RNDN);
  MPFR_ASSERTN (inex == 0);

  /* 0 < eps < 1 / (2n), thus (1 - eps)^n > 1/2,
     and 1/2 (1/2)^n < (1/2 - eps/2)^n < (1/2)^n. */
  mpfr_inits2 (64, z, z0, (mpfr_ptr) 0);
  RND_LOOP (rnd)
    {
      unsigned int ufinex = MPFR_FLAGS_UNDERFLOW | MPFR_FLAGS_INEXACT;
      int expected_inex;
      char sy[256];

      mpfr_set_ui (z0, 0, MPFR_RNDN);
      expected_inex = rnd == MPFR_RNDN || rnd == MPFR_RNDU || rnd == MPFR_RNDA ?
        (mpfr_nextabove (z0), 1) : -1;
      sprintf (sy, "%lu", (unsigned long) n);

      mpfr_clear_flags ();
      inex = mpfr_pow (z, x, y, (mpfr_rnd_t) rnd);
      cmpres (0, x, sy, (mpfr_rnd_t) rnd, z0, expected_inex, z, inex, ufinex,
              "underflow_up2", "mpfr_pow");
      test_others (NULL, sy, (mpfr_rnd_t) rnd, x, y, z, inex, ufinex,
                   "underflow_up2");
    }

  mpfr_clears (x, y, z, z0, eps, (mpfr_ptr) 0);
}
Exemple #3
0
void coords_center_to_rect(coords* c)
{
    mpfr_t tmp;
    mpfr_init2(tmp, c->precision);

    DMSG("updating from center to rect\n");

    if (c->aspect > 1.0)
    {
        DMSG("wide image");

        mpfr_div_d( c->height,  c->width,   c->aspect,  GMP_RNDN);

        mpfr_div_ui(tmp,        c->width,   2,          GMP_RNDN);
        mpfr_sub(   c->xmin,    c->cx,      tmp,        GMP_RNDN);
        mpfr_add(   c->xmax,    c->xmin,    c->width,   GMP_RNDN);

        mpfr_div_d( tmp,        tmp,        c->aspect,  GMP_RNDN);
        mpfr_sub(   c->ymin,    c->cy,      tmp,        GMP_RNDN);
        mpfr_add(   c->ymax,    c->ymin,    c->height,  GMP_RNDN);
    }
    else
    {
        DMSG("tall image");

        mpfr_mul_d( c->width,   c->height,  c->aspect,  GMP_RNDN);

        mpfr_div_ui(tmp,        c->height,  2,          GMP_RNDN);
        mpfr_sub(   c->ymin,    c->cy,      tmp,        GMP_RNDN);
        mpfr_add(   c->ymax,    c->ymin,    c->height,  GMP_RNDN);

        mpfr_mul_d( tmp,        tmp,        c->aspect,  GMP_RNDN);
        mpfr_sub(   c->xmin,    c->cx,      tmp,        GMP_RNDN);
        mpfr_add(   c->xmax,    c->xmin,    c->width,   GMP_RNDN);
    }

    mpfr_clear(tmp);
}
Exemple #4
0
int
main (int argc, char *argv[])
{
  mpfr_t x;

#ifdef HAVE_INFS
  check53 (DBL_NAN, DBL_NAN, GMP_RNDN);
  check53 (DBL_POS_INF, DBL_NAN, GMP_RNDN);
  check53 (DBL_NEG_INF, DBL_NAN, GMP_RNDN);
#endif
  /* worst case from PhD thesis of Vincent Lefe`vre: x=8980155785351021/2^54 */
  check53 (4.984987858808754279e-1, 4.781075595393330379e-1, GMP_RNDN);
  check53 (4.984987858808754279e-1, 4.781075595393329824e-1, GMP_RNDD);
  check53 (4.984987858808754279e-1, 4.781075595393329824e-1, GMP_RNDZ);
  check53 (4.984987858808754279e-1, 4.781075595393330379e-1, GMP_RNDU);
  check53 (1.00031274099908640274,  8.416399183372403892e-1, GMP_RNDN);
  check53 (1.00229256850978698523,  8.427074524447979442e-1, GMP_RNDZ);
  check53 (1.00288304857059840103,  8.430252033025980029e-1, GMP_RNDZ);
  check53 (1.00591265847407274059,  8.446508805292128885e-1, GMP_RNDN);

  check53 (1.00591265847407274059,  8.446508805292128885e-1, GMP_RNDN);

  mpfr_init2 (x, 2);

  mpfr_set_d (x, 0.5, GMP_RNDN);
  mpfr_sin (x, x, GMP_RNDD);
  if (mpfr_get_d1 (x) != 0.375)
    {
      fprintf (stderr, "mpfr_sin(0.5, GMP_RNDD) failed with precision=2\n");
      exit (1);
    }

  /* bug found by Kevin Ryde */
  mpfr_const_pi (x, GMP_RNDN);
  mpfr_mul_ui (x, x, 3L, GMP_RNDN);
  mpfr_div_ui (x, x, 2L, GMP_RNDN);
  mpfr_sin (x, x, GMP_RNDN);
  if (mpfr_cmp_ui (x, 0) >= 0)
    {
      fprintf (stderr, "Error: wrong sign for sin(3*Pi/2)\n");
      exit (1);
    }

  mpfr_clear (x);

  test_generic (2, 100, 80);

  return 0;
}
Exemple #5
0
//-----------------------------------------------------------
// base <- exp((1/2) sqrt(ln(n) ln(ln(n))))
//-----------------------------------------------------------
void get_smoothness_base(mpz_t base, mpz_t n) {
	mpfr_t fN, lnN, lnlnN;
	mpfr_init(fN), mpfr_init(lnN), mpfr_init(lnlnN);

	mpfr_set_z(fN, n, MPFR_RNDU);
	mpfr_log(lnN, fN, MPFR_RNDU);
	mpfr_log(lnlnN, lnN, MPFR_RNDU);

	mpfr_mul(fN, lnN, lnlnN, MPFR_RNDU);
	mpfr_sqrt(fN, fN, MPFR_RNDU);
	mpfr_div_ui(fN, fN, 2, MPFR_RNDU);
	mpfr_exp(fN, fN, MPFR_RNDU);

	mpfr_get_z(base, fN, MPFR_RNDU);

	mpfr_clears(fN, lnN, lnlnN, NULL);
}
Exemple #6
0
__inline__ static void
log2_L2_norm_4arg(mpfr_t tgt, const mpz_square_mat_t A, slong k, slong n)
// log2(L2 norm) rounded down. tgt initialized by caller
 {
  mpz_t norm; mpz_init(norm);
  slong i;
  square_L2_mpz(norm,A->rows[k],n);
  i=mpz_size(norm);
  if(i>2)
   i=2;
  mpfr_t normF; mpfr_init2(normF,i*FLINT_BITS);
  mpfr_set_z(normF,norm,MPFR_RNDU);
  mpz_clear(norm);
  mpfr_log2(tgt, normF, MPFR_RNDU);
  mpfr_div_ui(tgt,tgt,2,MPFR_RNDU);
  mpfr_clear(normF);
 }
Exemple #7
0
/*
   Parameters:
   s - the input floating-point number
   n, p - parameters from the algorithm
   tc - an array of p floating-point numbers tc[1]..tc[p]
   Output:
   b is the result, i.e.
   sum(tc[i]*product((s+2j)*(s+2j-1)/n^2,j=1..i-1), i=1..p)*s*n^(-s-1)
*/
static void
mpfr_zeta_part_b (mpfr_t b, mpfr_srcptr s, int n, int p, mpfr_t *tc)
{
  mpfr_t s1, d, u;
  unsigned long n2;
  int l, t;
  MPFR_GROUP_DECL (group);

  if (p == 0)
    {
      MPFR_SET_ZERO (b);
      MPFR_SET_POS (b);
      return;
    }

  n2 = n * n;
  MPFR_GROUP_INIT_3 (group, MPFR_PREC (b), s1, d, u);

  /* t equals 2p-2, 2p-3, ... ; s1 equals s+t */
  t = 2 * p - 2;
  mpfr_set (d, tc[p], GMP_RNDN);
  for (l = 1; l < p; l++)
    {
      mpfr_add_ui (s1, s, t, GMP_RNDN); /* s + (2p-2l) */
      mpfr_mul (d, d, s1, GMP_RNDN);
      t = t - 1;
      mpfr_add_ui (s1, s, t, GMP_RNDN); /* s + (2p-2l-1) */
      mpfr_mul (d, d, s1, GMP_RNDN);
      t = t - 1;
      mpfr_div_ui (d, d, n2, GMP_RNDN);
      mpfr_add (d, d, tc[p-l], GMP_RNDN);
      /* since s is positive and the tc[i] have alternate signs,
         the following is unlikely */
      if (MPFR_UNLIKELY (mpfr_cmpabs (d, tc[p-l]) > 0))
        mpfr_set (d, tc[p-l], GMP_RNDN);
    }
  mpfr_mul (d, d, s, GMP_RNDN);
  mpfr_add (s1, s, __gmpfr_one, GMP_RNDN);
  mpfr_neg (s1, s1, GMP_RNDN);
  mpfr_ui_pow (u, n, s1, GMP_RNDN);
  mpfr_mul (b, d, u, GMP_RNDN);

  MPFR_GROUP_CLEAR (group);
}
Exemple #8
0
static void
check (const char *ds, unsigned long u, mpfr_rnd_t rnd, const char *es)
{
  mpfr_t x, y;

  mpfr_init2 (x, 53);
  mpfr_init2 (y, 53);
  mpfr_set_str1 (x, ds);
  mpfr_div_ui (y, x, u, rnd);
  if (mpfr_cmp_str1 (y, es))
    {
      printf ("mpfr_div_ui failed for x=%s, u=%lu, rnd=%s\n", ds, u,
              mpfr_print_rnd_mode (rnd));
      printf ("expected result is %s, got", es);
      mpfr_out_str(stdout, 10, 0, y, MPFR_RNDN);
      exit (1);
    }
  mpfr_clear (x);
  mpfr_clear (y);
}
Exemple #9
0
slong
hadamard_2arg(mpfr_t b,const fmpz_mat_t m)
/*
upper bound on log2( 2*abs(m det) )
returns -1 if zero row found, smallest row index otherwise

b on entry is uninitialized
b on exit is initialized iff no zero row found
*/
 {
  const slong n=m->r;
  slong smallest=0,j;
  // gcc warning: initialization from incompatible pointer type --- don't know
  //  how to fix
  const fmpz** const rows=m->rows;
  mpfr_t v,u;
  if(log2_L2_fmpz_3arg( v, rows[0], n ))
   return -1;
  mpfr_copy_bound(b, v);
  // v and b must be freed
  for(j=1;j<n;j++)
   {
    if(log2_L2_fmpz_3arg( u, rows[j], n ))
     {
      mpfr_clear(b); mpfr_clear(v);
      return -1;
     }
    mpfr_add_bound(b, u);
    if( mpfr_cmp(u, v)<0 )
     {
      smallest=j;
      mpfr_swap(v, u);
     }
    mpfr_clear(u);
    // v and b must be freed
   }
  mpfr_clear(v);
  mpfr_div_ui( b, b, 2, MPFR_RNDU ); // instead of taking root
  mpfr_add_ui( b, b, 1, MPFR_RNDU ); // instead of multiplying by 2
  return smallest;
 }
Exemple #10
0
void fft_init(size_t N, mpfr_prec_t prec)
{
	if (prec) precision = prec;
	if (N) LEN = N;
	twid_fact = (Sequence) calloc(LEN, sizeof(mpc_t));
	mpfr_init_set_d(ZERO, 0.0, MPFR_RNDA);
	mpfr_init2(tmp, precision);
	mpfr_const_pi(tmp, MPFR_RNDA);
	mpfr_mul_si(tmp, tmp, -2, MPFR_RNDA);
	mpfr_div_ui(tmp, tmp, N, MPFR_RNDA);
	mpc_init2(min2pii, precision);
	mpc_set_fr_fr(min2pii, ZERO, tmp, RND);
	mpc_init2(temp, precision);
	new_seq = (Sequence) calloc(N, sizeof(mpc_t));
	size_t n = N / 2;
	while (n--)
	{
		mpc_init2(twid_fact + n, precision);
		mpc_mul_ui(twid_fact + n, min2pii, n, RND);
		mpc_exp(twid_fact + n, twid_fact + n, RND);
	}
}
void MathUtils::GetSmoothnessBase(mpz_class& ret_base, mpz_class& N)
{
	mpfr_t f_N, log_N, log_log_N;
	mpz_t base_mpz;
	mpz_init(base_mpz);

	mpfr_init(f_N); mpfr_init(log_N); mpfr_init(log_log_N);

	mpfr_set_z(f_N, N.get_mpz_t(), MPFR_RNDU);		//f_N = N
	mpfr_log(log_N, f_N, MPFR_RNDU); 				//log_N = log(N)
	mpfr_log(log_log_N, log_N, MPFR_RNDU); 			//log_log_N = log(log(N))

	mpfr_mul(f_N, log_N, log_log_N, MPFR_RNDU); 	//f_N = log(N) * log(log(N))
	mpfr_sqrt(f_N, f_N, MPFR_RNDU); 				//f_N = sqrt(f_N)

	mpfr_div_ui(f_N, f_N, 2, MPFR_RNDU);  			//f_N = f_N/2
	mpfr_exp(f_N, f_N, MPFR_RNDU);					//f_N = e^f_N

	mpfr_get_z(base_mpz, f_N, MPFR_RNDU);
	ret_base = mpz_class(base_mpz);

	mpfr_clears(f_N, log_N, log_log_N, NULL);
}
Exemple #12
0
/* try asymptotic expansion when x is large and positive:
   Li2(x) = -log(x)^2/2 + Pi^2/3 - 1/x + O(1/x^2).
   More precisely for x >= 2 we have for g(x) = -log(x)^2/2 + Pi^2/3:
   -2 <= x * (Li2(x) - g(x)) <= -1
   thus |Li2(x) - g(x)| <= 2/x.
   Assumes x >= 38, which ensures log(x)^2/2 >= 2*Pi^2/3, and g(x) <= -3.3.
   Return 0 if asymptotic expansion failed (unable to round), otherwise
   returns correct ternary value.
*/
static int
mpfr_li2_asympt_pos (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
{
  mpfr_t g, h;
  mp_prec_t w = MPFR_PREC (y) + 20;
  int inex = 0;

  MPFR_ASSERTN (mpfr_cmp_ui (x, 38) >= 0);

  mpfr_init2 (g, w);
  mpfr_init2 (h, w);
  mpfr_log (g, x, GMP_RNDN);    /* rel. error <= |(1 + theta) - 1| */
  mpfr_sqr (g, g, GMP_RNDN);    /* rel. error <= |(1 + theta)^3 - 1| <= 2^(2-w) */
  mpfr_div_2ui (g, g, 1, GMP_RNDN);     /* rel. error <= 2^(2-w) */
  mpfr_const_pi (h, GMP_RNDN);  /* error <= 2^(1-w) */
  mpfr_sqr (h, h, GMP_RNDN);    /* rel. error <= 2^(2-w) */
  mpfr_div_ui (h, h, 3, GMP_RNDN);      /* rel. error <= |(1 + theta)^4 - 1|
                                           <= 5 * 2^(-w) */
  /* since x is chosen such that log(x)^2/2 >= 2 * (Pi^2/3), we should have
     g >= 2*h, thus |g-h| >= |h|, and the relative error on g is at most
     multiplied by 2 in the difference, and that by h is unchanged. */
  MPFR_ASSERTN (MPFR_EXP (g) > MPFR_EXP (h));
  mpfr_sub (g, h, g, GMP_RNDN); /* err <= ulp(g)/2 + g*2^(3-w) + g*5*2^(-w)
                                   <= ulp(g) * (1/2 + 8 + 5) < 14 ulp(g).

                                   If in addition 2/x <= 2 ulp(g), i.e.,
                                   1/x <= ulp(g), then the total error is
                                   bounded by 16 ulp(g). */
  if ((MPFR_EXP (x) >= (mp_exp_t) w - MPFR_EXP (g)) &&
      MPFR_CAN_ROUND (g, w - 4, MPFR_PREC (y), rnd_mode))
    inex = mpfr_set (y, g, rnd_mode);

  mpfr_clear (g);
  mpfr_clear (h);

  return inex;
}
Exemple #13
0
int
main (int argc, char *argv[])
{
  mpfr_t x, c, s, c2, s2;

  tests_start_mpfr ();

  check_regression ();
  check_nans ();

  /* worst case from PhD thesis of Vincent Lefe`vre: x=8980155785351021/2^54 */
  check53 ("4.984987858808754279e-1", "4.781075595393330379e-1", MPFR_RNDN);
  check53 ("4.984987858808754279e-1", "4.781075595393329824e-1", MPFR_RNDD);
  check53 ("4.984987858808754279e-1", "4.781075595393329824e-1", MPFR_RNDZ);
  check53 ("4.984987858808754279e-1", "4.781075595393330379e-1", MPFR_RNDU);
  check53 ("1.00031274099908640274",  "8.416399183372403892e-1", MPFR_RNDN);
  check53 ("1.00229256850978698523",  "8.427074524447979442e-1", MPFR_RNDZ);
  check53 ("1.00288304857059840103",  "8.430252033025980029e-1", MPFR_RNDZ);
  check53 ("1.00591265847407274059",  "8.446508805292128885e-1", MPFR_RNDN);

  /* Other worst cases showing a bug introduced on 2005-01-29 in rev 3248 */
  check53b ("1.0111001111010111010111111000010011010001110001111011e-21",
            "1.0111001111010111010111111000010011010001101001110001e-21",
            MPFR_RNDU);
  check53b ("1.1011101111111010000001010111000010000111100100101101",
            "1.1111100100101100001111100000110011110011010001010101e-1",
            MPFR_RNDU);

  mpfr_init2 (x, 2);

  mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
  test_sin (x, x, MPFR_RNDD);
  if (mpfr_cmp_ui_2exp (x, 3, -3)) /* x != 0.375 = 3/8 */
    {
      printf ("mpfr_sin(0.5, MPFR_RNDD) failed with precision=2\n");
      exit (1);
    }

  /* bug found by Kevin Ryde */
  mpfr_const_pi (x, MPFR_RNDN);
  mpfr_mul_ui (x, x, 3L, MPFR_RNDN);
  mpfr_div_ui (x, x, 2L, MPFR_RNDN);
  test_sin (x, x, MPFR_RNDN);
  if (mpfr_cmp_ui (x, 0) >= 0)
    {
      printf ("Error: wrong sign for sin(3*Pi/2)\n");
      exit (1);
    }

  /* Can fail on an assert */
  mpfr_set_prec (x, 53);
  mpfr_set_str (x, "77291789194529019661184401408", 10, MPFR_RNDN);
  mpfr_init2 (c, 4); mpfr_init2 (s, 42);
  mpfr_init2 (c2, 4); mpfr_init2 (s2, 42);

  test_sin (s, x, MPFR_RNDN);
  mpfr_cos (c, x, MPFR_RNDN);
  mpfr_sin_cos (s2, c2, x, MPFR_RNDN);
  if (mpfr_cmp (c2, c))
    {
      printf("cos differs for x=77291789194529019661184401408");
      exit (1);
    }
  if (mpfr_cmp (s2, s))
    {
      printf("sin differs for x=77291789194529019661184401408");
      exit (1);
    }

  mpfr_set_str_binary (x, "1.1001001000011111101101010100010001000010110100010011");
  test_sin (x, x, MPFR_RNDZ);
  if (mpfr_cmp_str (x, "1.1111111111111111111111111111111111111111111111111111e-1", 2, MPFR_RNDN))
    {
      printf ("Error for x= 1.1001001000011111101101010100010001000010110100010011\nGot ");
      mpfr_dump (x);
      exit (1);
    }

  mpfr_set_prec (s, 9);
  mpfr_set_prec (x, 190);
  mpfr_const_pi (x, MPFR_RNDN);
  mpfr_sin (s, x, MPFR_RNDZ);
  if (mpfr_cmp_str (s, "0.100000101e-196", 2, MPFR_RNDN))
    {
      printf ("Error for x ~= pi\n");
      mpfr_dump (s);
      exit (1);
    }

  mpfr_clear (s2);
  mpfr_clear (c2);
  mpfr_clear (s);
  mpfr_clear (c);
  mpfr_clear (x);

  test_generic (2, 100, 15);
  test_generic (MPFR_SINCOS_THRESHOLD-1, MPFR_SINCOS_THRESHOLD+1, 2);
  test_sign ();
  check_tiny ();

  data_check ("data/sin", mpfr_sin, "mpfr_sin");
  bad_cases (mpfr_sin, mpfr_asin, "mpfr_sin", 256, -40, 0, 4, 128, 800, 50);

  tests_end_mpfr ();
  return 0;
}
Exemple #14
0
/* Implements asymptotic expansion for jn or yn (formulae 9.2.5 and 9.2.6
   from Abramowitz & Stegun).
   Assumes |z| > p log(2)/2, where p is the target precision
   (z can be negative only for jn).
   Return 0 if the expansion does not converge enough (the value 0 as inexact
   flag should not happen for normal input).
*/
static int
FUNCTION (mpfr_ptr res, long n, mpfr_srcptr z, mpfr_rnd_t r)
{
  mpfr_t s, c, P, Q, t, iz, err_t, err_s, err_u;
  mpfr_prec_t w;
  long k;
  int inex, stop, diverge = 0;
  mpfr_exp_t err2, err;
  MPFR_ZIV_DECL (loop);

  mpfr_init (c);

  w = MPFR_PREC(res) + MPFR_INT_CEIL_LOG2(MPFR_PREC(res)) + 4;

  MPFR_ZIV_INIT (loop, w);
  for (;;)
    {
      mpfr_set_prec (c, w);
      mpfr_init2 (s, w);
      mpfr_init2 (P, w);
      mpfr_init2 (Q, w);
      mpfr_init2 (t, w);
      mpfr_init2 (iz, w);
      mpfr_init2 (err_t, 31);
      mpfr_init2 (err_s, 31);
      mpfr_init2 (err_u, 31);

      /* Approximate sin(z) and cos(z). In the following, err <= k means that
         the approximate value y and the true value x are related by
         y = x * (1 + u)^k with |u| <= 2^(-w), following Higham's method. */
      mpfr_sin_cos (s, c, z, MPFR_RNDN);
      if (MPFR_IS_NEG(z))
        mpfr_neg (s, s, MPFR_RNDN); /* compute jn/yn(|z|), fix sign later */
      /* The absolute error on s/c is bounded by 1/2 ulp(1/2) <= 2^(-w-1). */
      mpfr_add (t, s, c, MPFR_RNDN);
      mpfr_sub (c, s, c, MPFR_RNDN);
      mpfr_swap (s, t);
      /* now s approximates sin(z)+cos(z), and c approximates sin(z)-cos(z),
         with total absolute error bounded by 2^(1-w). */

      /* precompute 1/(8|z|) */
      mpfr_si_div (iz, MPFR_IS_POS(z) ? 1 : -1, z, MPFR_RNDN);   /* err <= 1 */
      mpfr_div_2ui (iz, iz, 3, MPFR_RNDN);

      /* compute P and Q */
      mpfr_set_ui (P, 1, MPFR_RNDN);
      mpfr_set_ui (Q, 0, MPFR_RNDN);
      mpfr_set_ui (t, 1, MPFR_RNDN); /* current term */
      mpfr_set_ui (err_t, 0, MPFR_RNDN); /* error on t */
      mpfr_set_ui (err_s, 0, MPFR_RNDN); /* error on P and Q (sum of errors) */
      for (k = 1, stop = 0; stop < 4; k++)
        {
          /* compute next term: t(k)/t(k-1) = (2n+2k-1)(2n-2k+1)/(8kz) */
          mpfr_mul_si (t, t, 2 * (n + k) - 1, MPFR_RNDN); /* err <= err_k + 1 */
          mpfr_mul_si (t, t, 2 * (n - k) + 1, MPFR_RNDN); /* err <= err_k + 2 */
          mpfr_div_ui (t, t, k, MPFR_RNDN);               /* err <= err_k + 3 */
          mpfr_mul (t, t, iz, MPFR_RNDN);                 /* err <= err_k + 5 */
          /* the relative error on t is bounded by (1+u)^(5k)-1, which is
             bounded by 6ku for 6ku <= 0.02: first |5 log(1+u)| <= |5.5u|
             for |u| <= 0.15, then |exp(5.5u)-1| <= 6u for |u| <= 0.02. */
          mpfr_mul_ui (err_t, t, 6 * k, MPFR_IS_POS(t) ? MPFR_RNDU : MPFR_RNDD);
          mpfr_abs (err_t, err_t, MPFR_RNDN); /* exact */
          /* the absolute error on t is bounded by err_t * 2^(-w) */
          mpfr_abs (err_u, t, MPFR_RNDU);
          mpfr_mul_2ui (err_u, err_u, w, MPFR_RNDU); /* t * 2^w */
          mpfr_add (err_u, err_u, err_t, MPFR_RNDU); /* max|t| * 2^w */
          if (stop >= 2)
            {
              /* take into account the neglected terms: t * 2^w */
              mpfr_div_2ui (err_s, err_s, w, MPFR_RNDU);
              if (MPFR_IS_POS(t))
                mpfr_add (err_s, err_s, t, MPFR_RNDU);
              else
                mpfr_sub (err_s, err_s, t, MPFR_RNDU);
              mpfr_mul_2ui (err_s, err_s, w, MPFR_RNDU);
              stop ++;
            }
          /* if k is odd, add to Q, otherwise to P */
          else if (k & 1)
            {
              /* if k = 1 mod 4, add, otherwise subtract */
              if ((k & 2) == 0)
                mpfr_add (Q, Q, t, MPFR_RNDN);
              else
                mpfr_sub (Q, Q, t, MPFR_RNDN);
              /* check if the next term is smaller than ulp(Q): if EXP(err_u)
                 <= EXP(Q), since the current term is bounded by
                 err_u * 2^(-w), it is bounded by ulp(Q) */
              if (MPFR_EXP(err_u) <= MPFR_EXP(Q))
                stop ++;
              else
                stop = 0;
            }
          else
            {
              /* if k = 0 mod 4, add, otherwise subtract */
              if ((k & 2) == 0)
                mpfr_add (P, P, t, MPFR_RNDN);
              else
                mpfr_sub (P, P, t, MPFR_RNDN);
              /* check if the next term is smaller than ulp(P) */
              if (MPFR_EXP(err_u) <= MPFR_EXP(P))
                stop ++;
              else
                stop = 0;
            }
          mpfr_add (err_s, err_s, err_t, MPFR_RNDU);
          /* the sum of the rounding errors on P and Q is bounded by
             err_s * 2^(-w) */

          /* stop when start to diverge */
          if (stop < 2 &&
              ((MPFR_IS_POS(z) && mpfr_cmp_ui (z, (k + 1) / 2) < 0) ||
               (MPFR_IS_NEG(z) && mpfr_cmp_si (z, - ((k + 1) / 2)) > 0)))
            {
              /* if we have to stop the series because it diverges, then
                 increasing the precision will most probably fail, since
                 we will stop to the same point, and thus compute a very
                 similar approximation */
              diverge = 1;
              stop = 2; /* force stop */
            }
        }
      /* the sum of the total errors on P and Q is bounded by err_s * 2^(-w) */

      /* Now combine: the sum of the rounding errors on P and Q is bounded by
         err_s * 2^(-w), and the absolute error on s/c is bounded by 2^(1-w) */
      if ((n & 1) == 0) /* n even: P * (sin + cos) + Q (cos - sin) for jn
                                   Q * (sin + cos) + P (sin - cos) for yn */
        {
#ifdef MPFR_JN
          mpfr_mul (c, c, Q, MPFR_RNDN); /* Q * (sin - cos) */
          mpfr_mul (s, s, P, MPFR_RNDN); /* P * (sin + cos) */
#else
          mpfr_mul (c, c, P, MPFR_RNDN); /* P * (sin - cos) */
          mpfr_mul (s, s, Q, MPFR_RNDN); /* Q * (sin + cos) */
#endif
          err = MPFR_EXP(c);
          if (MPFR_EXP(s) > err)
            err = MPFR_EXP(s);
#ifdef MPFR_JN
          mpfr_sub (s, s, c, MPFR_RNDN);
#else
          mpfr_add (s, s, c, MPFR_RNDN);
#endif
        }
      else /* n odd: P * (sin - cos) + Q (cos + sin) for jn,
                     Q * (sin - cos) - P (cos + sin) for yn */
        {
#ifdef MPFR_JN
          mpfr_mul (c, c, P, MPFR_RNDN); /* P * (sin - cos) */
          mpfr_mul (s, s, Q, MPFR_RNDN); /* Q * (sin + cos) */
#else
          mpfr_mul (c, c, Q, MPFR_RNDN); /* Q * (sin - cos) */
          mpfr_mul (s, s, P, MPFR_RNDN); /* P * (sin + cos) */
#endif
          err = MPFR_EXP(c);
          if (MPFR_EXP(s) > err)
            err = MPFR_EXP(s);
#ifdef MPFR_JN
          mpfr_add (s, s, c, MPFR_RNDN);
#else
          mpfr_sub (s, c, s, MPFR_RNDN);
#endif
        }
      if ((n & 2) != 0)
        mpfr_neg (s, s, MPFR_RNDN);
      if (MPFR_EXP(s) > err)
        err = MPFR_EXP(s);
      /* the absolute error on s is bounded by P*err(s/c) + Q*err(s/c)
         + err(P)*(s/c) + err(Q)*(s/c) + 3 * 2^(err - w - 1)
         <= (|P|+|Q|) * 2^(1-w) + err_s * 2^(1-w) + 2^err * 2^(1-w),
         since |c|, |old_s| <= 2. */
      err2 = (MPFR_EXP(P) >= MPFR_EXP(Q)) ? MPFR_EXP(P) + 2 : MPFR_EXP(Q) + 2;
      /* (|P| + |Q|) * 2^(1 - w) <= 2^(err2 - w) */
      err = MPFR_EXP(err_s) >= err ? MPFR_EXP(err_s) + 2 : err + 2;
      /* err_s * 2^(1-w) + 2^old_err * 2^(1-w) <= 2^err * 2^(-w) */
      err2 = (err >= err2) ? err + 1 : err2 + 1;
      /* now the absolute error on s is bounded by 2^(err2 - w) */

      /* multiply by sqrt(1/(Pi*z)) */
      mpfr_const_pi (c, MPFR_RNDN);     /* Pi, err <= 1 */
      mpfr_mul (c, c, z, MPFR_RNDN);    /* err <= 2 */
      mpfr_si_div (c, MPFR_IS_POS(z) ? 1 : -1, c, MPFR_RNDN); /* err <= 3 */
      mpfr_sqrt (c, c, MPFR_RNDN);      /* err<=5/2, thus the absolute error is
                                          bounded by 3*u*|c| for |u| <= 0.25 */
      mpfr_mul (err_t, c, s, MPFR_SIGN(c)==MPFR_SIGN(s) ? MPFR_RNDU : MPFR_RNDD);
      mpfr_abs (err_t, err_t, MPFR_RNDU);
      mpfr_mul_ui (err_t, err_t, 3, MPFR_RNDU);
      /* 3*2^(-w)*|old_c|*|s| [see below] is bounded by err_t * 2^(-w) */
      err2 += MPFR_EXP(c);
      /* |old_c| * 2^(err2 - w) [see below] is bounded by 2^(err2-w) */
      mpfr_mul (c, c, s, MPFR_RNDN);    /* the absolute error on c is bounded by
                                          1/2 ulp(c) + 3*2^(-w)*|old_c|*|s|
                                          + |old_c| * 2^(err2 - w) */
      /* compute err_t * 2^(-w) + 1/2 ulp(c) = (err_t + 2^EXP(c)) * 2^(-w) */
      err = (MPFR_EXP(err_t) > MPFR_EXP(c)) ? MPFR_EXP(err_t) + 1 : MPFR_EXP(c) + 1;
      /* err_t * 2^(-w) + 1/2 ulp(c) <= 2^(err - w) */
      /* now err_t * 2^(-w) bounds 1/2 ulp(c) + 3*2^(-w)*|old_c|*|s| */
      err = (err >= err2) ? err + 1 : err2 + 1;
      /* the absolute error on c is bounded by 2^(err - w) */

      mpfr_clear (s);
      mpfr_clear (P);
      mpfr_clear (Q);
      mpfr_clear (t);
      mpfr_clear (iz);
      mpfr_clear (err_t);
      mpfr_clear (err_s);
      mpfr_clear (err_u);

      err -= MPFR_EXP(c);
      if (MPFR_LIKELY (MPFR_CAN_ROUND (c, w - err, MPFR_PREC(res), r)))
        break;
      if (diverge != 0)
        {
          mpfr_set (c, z, r); /* will force inex=0 below, which means the
                               asymptotic expansion failed */
          break;
        }
      MPFR_ZIV_NEXT (loop, w);
    }
  MPFR_ZIV_FREE (loop);

  inex = (MPFR_IS_POS(z) || ((n & 1) == 0)) ? mpfr_set (res, c, r)
    : mpfr_neg (res, c, r);
  mpfr_clear (c);

  return inex;
}
Exemple #15
0
int
mpfr_erf (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
{
  mpfr_t xf;
  mp_limb_t xf_limb[(53 - 1) / GMP_NUMB_BITS + 1];
  int inex, large;
  MPFR_SAVE_EXPO_DECL (expo);

  MPFR_LOG_FUNC
    (("x[%Pu]=%.*Rg rnd=%d", mpfr_get_prec (x), mpfr_log_prec, x, rnd_mode),
     ("y[%Pu]=%.*Rg inexact=%d", mpfr_get_prec (y), mpfr_log_prec, y, inex));

  if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x)))
    {
      if (MPFR_IS_NAN (x))
        {
          MPFR_SET_NAN (y);
          MPFR_RET_NAN;
        }
      else if (MPFR_IS_INF (x)) /* erf(+inf) = +1, erf(-inf) = -1 */
        return mpfr_set_si (y, MPFR_INT_SIGN (x), MPFR_RNDN);
      else /* erf(+0) = +0, erf(-0) = -0 */
        {
          MPFR_ASSERTD (MPFR_IS_ZERO (x));
          return mpfr_set (y, x, MPFR_RNDN); /* should keep the sign of x */
        }
    }

  /* now x is neither NaN, Inf nor 0 */

  /* first try expansion at x=0 when x is small, or asymptotic expansion
     where x is large */

  MPFR_SAVE_EXPO_MARK (expo);

  /* around x=0, we have erf(x) = 2x/sqrt(Pi) (1 - x^2/3 + ...),
     with 1 - x^2/3 <= sqrt(Pi)*erf(x)/2/x <= 1 for x >= 0. This means that
     if x^2/3 < 2^(-PREC(y)-1) we can decide of the correct rounding,
     unless we have a worst-case for 2x/sqrt(Pi). */
  if (MPFR_EXP(x) < - (mpfr_exp_t) (MPFR_PREC(y) / 2))
    {
      /* we use 2x/sqrt(Pi) (1 - x^2/3) <= erf(x) <= 2x/sqrt(Pi) for x > 0
         and 2x/sqrt(Pi) <= erf(x) <= 2x/sqrt(Pi) (1 - x^2/3) for x < 0.
         In both cases |2x/sqrt(Pi) (1 - x^2/3)| <= |erf(x)| <= |2x/sqrt(Pi)|.
         We will compute l and h such that l <= |2x/sqrt(Pi) (1 - x^2/3)|
         and |2x/sqrt(Pi)| <= h. If l and h round to the same value to
         precision PREC(y) and rounding rnd_mode, then we are done. */
      mpfr_t l, h; /* lower and upper bounds for erf(x) */
      int ok, inex2;

      mpfr_init2 (l, MPFR_PREC(y) + 17);
      mpfr_init2 (h, MPFR_PREC(y) + 17);
      /* first compute l */
      mpfr_mul (l, x, x, MPFR_RNDU);
      mpfr_div_ui (l, l, 3, MPFR_RNDU); /* upper bound on x^2/3 */
      mpfr_ui_sub (l, 1, l, MPFR_RNDZ); /* lower bound on 1 - x^2/3 */
      mpfr_const_pi (h, MPFR_RNDU); /* upper bound of Pi */
      mpfr_sqrt (h, h, MPFR_RNDU); /* upper bound on sqrt(Pi) */
      mpfr_div (l, l, h, MPFR_RNDZ); /* lower bound on 1/sqrt(Pi) (1 - x^2/3) */
      mpfr_mul_2ui (l, l, 1, MPFR_RNDZ); /* 2/sqrt(Pi) (1 - x^2/3) */
      mpfr_mul (l, l, x, MPFR_RNDZ); /* |l| is a lower bound on
                                       |2x/sqrt(Pi) (1 - x^2/3)| */
      /* now compute h */
      mpfr_const_pi (h, MPFR_RNDD); /* lower bound on Pi */
      mpfr_sqrt (h, h, MPFR_RNDD); /* lower bound on sqrt(Pi) */
      mpfr_div_2ui (h, h, 1, MPFR_RNDD); /* lower bound on sqrt(Pi)/2 */
      /* since sqrt(Pi)/2 < 1, the following should not underflow */
      mpfr_div (h, x, h, MPFR_IS_POS(x) ? MPFR_RNDU : MPFR_RNDD);
      /* round l and h to precision PREC(y) */
      inex = mpfr_prec_round (l, MPFR_PREC(y), rnd_mode);
      inex2 = mpfr_prec_round (h, MPFR_PREC(y), rnd_mode);
      /* Caution: we also need inex=inex2 (inex might be 0). */
      ok = SAME_SIGN (inex, inex2) && mpfr_cmp (l, h) == 0;
      if (ok)
        mpfr_set (y, h, rnd_mode);
      mpfr_clear (l);
      mpfr_clear (h);
      if (ok)
        goto end;
      /* this test can still fail for small precision, for example
         for x=-0.100E-2 with a target precision of 3 bits, since
         the error term x^2/3 is not that small. */
    }

  MPFR_TMP_INIT1(xf_limb, xf, 53);
  mpfr_div (xf, x, __gmpfr_const_log2_RNDU, MPFR_RNDZ); /* round to zero
                        ensures we get a lower bound of |x/log(2)| */
  mpfr_mul (xf, xf, x, MPFR_RNDZ);
  large = mpfr_cmp_ui (xf, MPFR_PREC (y) + 1) > 0;

  /* when x goes to infinity, we have erf(x) = 1 - 1/sqrt(Pi)/exp(x^2)/x + ...
     and |erf(x) - 1| <= exp(-x^2) is true for any x >= 0, thus if
     exp(-x^2) < 2^(-PREC(y)-1) the result is 1 or 1-epsilon.
     This rewrites as x^2/log(2) > p+1. */
  if (MPFR_UNLIKELY (large))
    /* |erf x| = 1 or 1- */
    {
      mpfr_rnd_t rnd2 = MPFR_IS_POS (x) ? rnd_mode : MPFR_INVERT_RND(rnd_mode);
      if (rnd2 == MPFR_RNDN || rnd2 == MPFR_RNDU || rnd2 == MPFR_RNDA)
        {
          inex = MPFR_INT_SIGN (x);
          mpfr_set_si (y, inex, rnd2);
        }
      else /* round to zero */
        {
          inex = -MPFR_INT_SIGN (x);
          mpfr_setmax (y, 0); /* warning: setmax keeps the old sign of y */
          MPFR_SET_SAME_SIGN (y, x);
        }
    }
  else  /* use Taylor */
    {
      double xf2;

      /* FIXME: get rid of doubles/mpfr_get_d here */
      xf2 = mpfr_get_d (x, MPFR_RNDN);
      xf2 = xf2 * xf2; /* xf2 ~ x^2 */
      inex = mpfr_erf_0 (y, x, xf2, rnd_mode);
    }

 end:
  MPFR_SAVE_EXPO_FREE (expo);
  return mpfr_check_range (y, inex, rnd_mode);
}
Exemple #16
0
static void
check_1minuseps (void)
{
    static mpfr_prec_t prec_a[] = {
        MPFR_PREC_MIN, 30, 31, 32, 33, 62, 63, 64, 65, 126, 127, 128, 129
    };
    static int supp_b[] = {
        0, 1, 2, 3, 4, 29, 30, 31, 32, 33, 34, 35, 61, 62, 63, 64, 65, 66, 67
    };
    mpfr_t a, b, c;
    unsigned int ia, ib, ic;

    mpfr_init2 (c, MPFR_PREC_MIN);

    for (ia = 0; ia < numberof (prec_a); ia++)
        for (ib = 0; ib < numberof(supp_b); ib++)
        {
            mpfr_prec_t prec_b;
            int rnd_mode;

            prec_b = prec_a[ia] + supp_b[ib];

            mpfr_init2 (a, prec_a[ia]);
            mpfr_init2 (b, prec_b);

            mpfr_set_ui (c, 1, MPFR_RNDN);
            mpfr_div_ui (b, c, prec_a[ia], MPFR_RNDN);
            mpfr_sub (b, c, b, MPFR_RNDN);  /* b = 1 - 2^(-prec_a) */

            for (ic = 0; ic < numberof(supp_b); ic++)
                for (rnd_mode = 0; rnd_mode < MPFR_RND_MAX; rnd_mode++)
                {
                    mpfr_t s;
                    int inex_a, inex_s;

                    mpfr_set_ui (c, 1, MPFR_RNDN);
                    mpfr_div_ui (c, c, prec_a[ia] + supp_b[ic], MPFR_RNDN);
                    inex_a = test_add (a, b, c, (mpfr_rnd_t) rnd_mode);
                    mpfr_init2 (s, 256);
                    inex_s = test_add (s, b, c, MPFR_RNDN); /* exact */
                    if (inex_s)
                    {
                        printf ("check_1minuseps: result should have been exact "
                                "(ia = %u, ib = %u, ic = %u)\n", ia, ib, ic);
                        exit (1);
                    }
                    inex_s = mpfr_prec_round (s, prec_a[ia], (mpfr_rnd_t) rnd_mode);
                    if ((inex_a < 0 && inex_s >= 0) ||
                            (inex_a == 0 && inex_s != 0) ||
                            (inex_a > 0 && inex_s <= 0) ||
                            !mpfr_equal_p (a, s))
                    {
                        printf ("check_1minuseps: results are different.\n");
                        printf ("ia = %u, ib = %u, ic = %u\n", ia, ib, ic);
                        exit (1);
                    }
                    mpfr_clear (s);
                }

            mpfr_clear (a);
            mpfr_clear (b);
        }

    mpfr_clear (c);
}
void
_arith_cos_minpoly(fmpz * coeffs, slong d, ulong n)
{
    slong i, j;
    fmpz * alpha;
    fmpz_t half;
    mpfr_t t, u;
    mp_bitcnt_t prec;
    slong exp;

    if (n <= MAX_32BIT)
    {
        for (i = 0; i <= d; i++)
            fmpz_set_si(coeffs + i, lookup_table[n - 1][i]);
        return;
    }

    /* Direct formula for odd primes > 3 */
    if (n_is_prime(n))
    {
        slong s = (n - 1) / 2;

        switch (s % 4)
        {
            case 0:
                fmpz_set_si(coeffs, WORD(1));
                fmpz_set_si(coeffs + 1, -s);
                break;
            case 1:
                fmpz_set_si(coeffs, WORD(1));
                fmpz_set_si(coeffs + 1, s + 1);
                break;
            case 2:
                fmpz_set_si(coeffs, WORD(-1));
                fmpz_set_si(coeffs + 1, s);
                break;
            case 3:
                fmpz_set_si(coeffs, WORD(-1));
                fmpz_set_si(coeffs + 1, -s - 1);
                break;
        }

        for (i = 2; i <= s; i++)
        {
            slong b = (s - i) % 2;
            fmpz_mul2_uiui(coeffs + i, coeffs + i - 2, s+i-b, s+2-b-i);
            fmpz_divexact2_uiui(coeffs + i, coeffs + i, i, i-1);
            fmpz_neg(coeffs + i, coeffs + i);
        }

        return;
    }

    prec = magnitude_bound(d) + 5 + FLINT_BIT_COUNT(d);

    alpha = _fmpz_vec_init(d);
    fmpz_init(half);
    mpfr_init2(t, prec);
    mpfr_init2(u, prec);

    fmpz_one(half);
    fmpz_mul_2exp(half, half, prec - 1);
    mpfr_const_pi(t, prec);
    mpfr_div_ui(t, t, n, MPFR_RNDN);

    for (i = j = 0; j < d; i++)
    {
        if (n_gcd(n, i) == 1)
        {
            mpfr_mul_ui(u, t, 2 * i, MPFR_RNDN);
            mpfr_cos(u, u, MPFR_RNDN);
            mpfr_neg(u, u, MPFR_RNDN);
            exp = mpfr_get_z_2exp(_fmpz_promote(alpha + j), u);
            _fmpz_demote_val(alpha + j);
            fmpz_mul_or_div_2exp(alpha + j, alpha + j, exp + prec);
            j++;
        }
    }

    balanced_product(coeffs, alpha, d, prec);

    /* Scale and round */
    for (i = 0; i < d + 1; i++)
    {
        slong r = d;
        if ((n & (n - 1)) == 0)
            r--;
        fmpz_mul_2exp(coeffs + i, coeffs + i, r);
        fmpz_add(coeffs + i, coeffs + i, half);
        fmpz_fdiv_q_2exp(coeffs + i, coeffs + i, prec);
    }

    fmpz_clear(half);
    mpfr_clear(t);
    mpfr_clear(u);
    _fmpz_vec_clear(alpha, d);
}
Exemple #18
0
int
main (void)
{
  mpfr_t  x;

  mpfr_init (x);

  /* check +infinity gives non-zero for mpfr_inf_p only */
  mpfr_set_ui (x, 1L, GMP_RNDZ);
  mpfr_div_ui (x, x, 0L, GMP_RNDZ);
  if (mpfr_nan_p (x)) {
    fprintf (stderr, "Error: mpfr_nan_p(+Inf) gives non-zero\n");
    exit (1);
  }
  if (mpfr_inf_p (x) == 0) {
    fprintf (stderr, "Error: mpfr_inf_p(+Inf) gives zero\n");
    exit (1);
  }
  if (mpfr_number_p (x)) {
    fprintf (stderr, "Error: mpfr_number_p(+Inf) gives non-zero\n");
    exit (1);
  }

  /* same for -Inf */
  mpfr_neg (x, x, GMP_RNDN);
  if (mpfr_nan_p (x)) {
    fprintf (stderr, "Error: mpfr_nan_p(-Inf) gives non-zero\n");
    exit (1);
  }
  if (mpfr_inf_p (x) == 0) {
    fprintf (stderr, "Error: mpfr_inf_p(-Inf) gives zero\n");
    exit (1);
  }
  if (mpfr_number_p (x)) {
    fprintf (stderr, "Error: mpfr_number_p(-Inf) gives non-zero\n");
    exit (1);
  }

  /* same for NaN */
  mpfr_sub (x, x, x, GMP_RNDN);
  if (mpfr_nan_p (x) == 0) {
    fprintf (stderr, "Error: mpfr_nan_p(NaN) gives zero\n");
    exit (1);
  }
  if (mpfr_inf_p (x)) {
    fprintf (stderr, "Error: mpfr_inf_p(NaN) gives non-zero\n");
    exit (1);
  }
  if (mpfr_number_p (x)) {
    fprintf (stderr, "Error: mpfr_number_p(NaN) gives non-zero\n");
    exit (1);
  }

  /* same for an ordinary number */
  mpfr_set_ui (x, 1, GMP_RNDN);
  if (mpfr_nan_p (x)) {
    fprintf (stderr, "Error: mpfr_nan_p(1) gives non-zero\n");
    exit (1);
  }
  if (mpfr_inf_p (x)) {
    fprintf (stderr, "Error: mpfr_inf_p(1) gives non-zero\n");
    exit (1);
  }
  if (mpfr_number_p (x) == 0) {
    fprintf (stderr, "Error: mpfr_number_p(1) gives zero\n");
    exit (1);
  }

  mpfr_clear (x);

  return 0;
}
Exemple #19
0
/* compute in y an approximation of sum(x^k/k/k!, k=1..infinity),
   and return e such that the absolute error is bound by 2^e ulp(y) */
static mp_exp_t
mpfr_eint_aux (mpfr_t y, mpfr_srcptr x)
{
  mpfr_t eps; /* dynamic (absolute) error bound on t */
  mpfr_t erru, errs;
  mpz_t m, s, t, u;
  mp_exp_t e, sizeinbase;
  mp_prec_t w = MPFR_PREC(y);
  unsigned long k;
  MPFR_GROUP_DECL (group);

  /* for |x| <= 1, we have S := sum(x^k/k/k!, k=1..infinity) = x + R(x)
     where |R(x)| <= (x/2)^2/(1-x/2) <= 2*(x/2)^2
     thus |R(x)/x| <= |x|/2
     thus if |x| <= 2^(-PREC(y)) we have |S - o(x)| <= ulp(y) */

  if (MPFR_GET_EXP(x) <= - (mp_exp_t) w)
    {
      mpfr_set (y, x, GMP_RNDN);
      return 0;
    }

  mpz_init (s); /* initializes to 0 */
  mpz_init (t);
  mpz_init (u);
  mpz_init (m);
  MPFR_GROUP_INIT_3 (group, 31, eps, erru, errs);
  e = mpfr_get_z_exp (m, x); /* x = m * 2^e */
  MPFR_ASSERTD (mpz_sizeinbase (m, 2) == MPFR_PREC (x));
  if (MPFR_PREC (x) > w)
    {
      e += MPFR_PREC (x) - w;
      mpz_tdiv_q_2exp (m, m, MPFR_PREC (x) - w);
    }
  /* remove trailing zeroes from m: this will speed up much cases where
     x is a small integer divided by a power of 2 */
  k = mpz_scan1 (m, 0);
  mpz_tdiv_q_2exp (m, m, k);
  e += k;
  /* initialize t to 2^w */
  mpz_set_ui (t, 1);
  mpz_mul_2exp (t, t, w);
  mpfr_set_ui (eps, 0, GMP_RNDN); /* eps[0] = 0 */
  mpfr_set_ui (errs, 0, GMP_RNDN);
  for (k = 1;; k++)
    {
      /* let eps[k] be the absolute error on t[k]:
         since t[k] = trunc(t[k-1]*m*2^e/k), we have
         eps[k+1] <= 1 + eps[k-1]*m*2^e/k + t[k-1]*m*2^(1-w)*2^e/k
                  =  1 + (eps[k-1] + t[k-1]*2^(1-w))*m*2^e/k
                  = 1 + (eps[k-1]*2^(w-1) + t[k-1])*2^(1-w)*m*2^e/k */
      mpfr_mul_2ui (eps, eps, w - 1, GMP_RNDU);
      mpfr_add_z (eps, eps, t, GMP_RNDU);
      MPFR_MPZ_SIZEINBASE2 (sizeinbase, m);
      mpfr_mul_2si (eps, eps, sizeinbase - (w - 1) + e, GMP_RNDU);
      mpfr_div_ui (eps, eps, k, GMP_RNDU);
      mpfr_add_ui (eps, eps, 1, GMP_RNDU);
      mpz_mul (t, t, m);
      if (e < 0)
        mpz_tdiv_q_2exp (t, t, -e);
      else
        mpz_mul_2exp (t, t, e);
      mpz_tdiv_q_ui (t, t, k);
      mpz_tdiv_q_ui (u, t, k);
      mpz_add (s, s, u);
      /* the absolute error on u is <= 1 + eps[k]/k */
      mpfr_div_ui (erru, eps, k, GMP_RNDU);
      mpfr_add_ui (erru, erru, 1, GMP_RNDU);
      /* and that on s is the sum of all errors on u */
      mpfr_add (errs, errs, erru, GMP_RNDU);
      /* we are done when t is smaller than errs */
      if (mpz_sgn (t) == 0)
        sizeinbase = 0;
      else
        MPFR_MPZ_SIZEINBASE2 (sizeinbase, t);
      if (sizeinbase < MPFR_GET_EXP (errs))
        break;
    }
  /* the truncation error is bounded by (|t|+eps)/k*(|x|/k + |x|^2/k^2 + ...)
     <= (|t|+eps)/k*|x|/(k-|x|) */
  mpz_abs (t, t);
  mpfr_add_z (eps, eps, t, GMP_RNDU);
  mpfr_div_ui (eps, eps, k, GMP_RNDU);
  mpfr_abs (erru, x, GMP_RNDU); /* |x| */
  mpfr_mul (eps, eps, erru, GMP_RNDU);
  mpfr_ui_sub (erru, k, erru, GMP_RNDD);
  if (MPFR_IS_NEG (erru))
    {
      /* the truncated series does not converge, return fail */
      e = w;
    }
  else
    {
      mpfr_div (eps, eps, erru, GMP_RNDU);
      mpfr_add (errs, errs, eps, GMP_RNDU);
      mpfr_set_z (y, s, GMP_RNDN);
      mpfr_div_2ui (y, y, w, GMP_RNDN);
      /* errs was an absolute error bound on s. We must convert it to an error
         in terms of ulp(y). Since ulp(y) = 2^(EXP(y)-PREC(y)), we must
         divide the error by 2^(EXP(y)-PREC(y)), but since we divided also
         y by 2^w = 2^PREC(y), we must simply divide by 2^EXP(y). */
      e = MPFR_GET_EXP (errs) - MPFR_GET_EXP (y);
    }
  MPFR_GROUP_CLEAR (group);
  mpz_clear (s);
  mpz_clear (t);
  mpz_clear (u);
  mpz_clear (m);
  return e;
}
void generate_2D_sample (FILE *output, struct speed_params2D param)
{
  mpfr_t temp;
  double incr_prec;
  mpfr_t incr_x;
  mpfr_t x, x2;
  double prec;
  struct speed_params s;
  int i;
  int test;
  int nb_functions;
  double *t; /* store the timing of each implementation */

  /* We first determine how many implementations we have */
  nb_functions = 0;
  while (param.speed_funcs[nb_functions] != NULL)
    nb_functions++;

  t = malloc (nb_functions * sizeof (double));
  if (t == NULL)
    {
      fprintf (stderr, "Can't allocate memory.\n");
      abort ();
    }


  mpfr_init2 (temp, MPFR_SMALL_PRECISION);

  /* The precision is sampled from min_prec to max_prec with        */
  /* approximately nb_points_prec points. If logarithmic_scale_prec */
  /* is true, the precision is multiplied by incr_prec at each      */
  /* step. Otherwise, incr_prec is added at each step.              */
  if (param.logarithmic_scale_prec)
    {
      mpfr_set_ui (temp, (unsigned long int)param.max_prec, MPFR_RNDU);
      mpfr_div_ui (temp, temp, (unsigned long int)param.min_prec, MPFR_RNDU);
      mpfr_root (temp, temp,
                 (unsigned long int)param.nb_points_prec, MPFR_RNDU);
      incr_prec = mpfr_get_d (temp, MPFR_RNDU);
    }
  else
    {
      incr_prec = (double)param.max_prec - (double)param.min_prec;
      incr_prec = incr_prec/((double)param.nb_points_prec);
    }

  /* The points x are sampled according to the following rule:             */
  /* If logarithmic_scale_x = 0:                                           */
  /*    nb_points_x points are equally distributed between min_x and max_x */
  /* If logarithmic_scale_x = 1:                                           */
  /*    nb_points_x points are sampled from 2^(min_x) to 2^(max_x). At     */
  /*    each step, the current point is multiplied by incr_x.              */
  /* If logarithmic_scale_x = -1:                                          */
  /*    nb_points_x/2 points are sampled from -2^(max_x) to -2^(min_x)     */
  /*    (at each step, the current point is divided by incr_x);  and       */
  /*    nb_points_x/2 points are sampled from 2^(min_x) to 2^(max_x)       */
  /*    (at each step, the current point is multiplied by incr_x).         */
  mpfr_init2 (incr_x, param.max_prec);
  if (param.logarithmic_scale_x == 0)
    {
      mpfr_set_d (incr_x,
                  (param.max_x - param.min_x)/(double)param.nb_points_x,
                  MPFR_RNDU);
    }
  else if (param.logarithmic_scale_x == -1)
    {
      mpfr_set_d (incr_x,
                  2.*(param.max_x - param.min_x)/(double)param.nb_points_x,
                  MPFR_RNDU);
      mpfr_exp2 (incr_x, incr_x, MPFR_RNDU);
    }
  else
    { /* other values of param.logarithmic_scale_x are considered as 1 */
      mpfr_set_d (incr_x,
                  (param.max_x - param.min_x)/(double)param.nb_points_x,
                  MPFR_RNDU);
      mpfr_exp2 (incr_x, incr_x, MPFR_RNDU);
    }

  /* Main loop */
  mpfr_init2 (x, param.max_prec);
  mpfr_init2 (x2, param.max_prec);
  prec = (double)param.min_prec;
  while (prec <= param.max_prec)
    {
      printf ("prec = %d\n", (int)prec);
      if (param.logarithmic_scale_x == 0)
        mpfr_set_d (temp, param.min_x, MPFR_RNDU);
      else if (param.logarithmic_scale_x == -1)
        {
          mpfr_set_d (temp, param.max_x, MPFR_RNDD);
          mpfr_exp2 (temp, temp, MPFR_RNDD);
          mpfr_neg (temp, temp, MPFR_RNDU);
        }
      else
        {
          mpfr_set_d (temp, param.min_x, MPFR_RNDD);
          mpfr_exp2 (temp, temp, MPFR_RNDD);
        }

      /* We perturb x a little bit, in order to avoid trailing zeros that */
      /* might change the behavior of algorithms.                         */
      mpfr_const_pi (x, MPFR_RNDN);
      mpfr_div_2ui (x, x, 7, MPFR_RNDN);
      mpfr_add_ui (x, x, 1, MPFR_RNDN);
      mpfr_mul (x, x, temp, MPFR_RNDN);

      test = 1;
      while (test)
        {
          mpfr_fprintf (output, "%e\t", mpfr_get_d (x, MPFR_RNDN));
          mpfr_fprintf (output, "%Pu\t", (mpfr_prec_t)prec);

          s.r = (mp_limb_t)mpfr_get_exp (x);
          s.size = (mpfr_prec_t)prec;
          s.align_xp = (mpfr_sgn (x) > 0)?1:2;
          mpfr_set_prec (x2, (mpfr_prec_t)prec);
          mpfr_set (x2, x, MPFR_RNDU);
          s.xp = x2->_mpfr_d;

          for (i=0; i<nb_functions; i++)
            {
              t[i] = speed_measure (param.speed_funcs[i], &s);
              mpfr_fprintf (output, "%e\t", t[i]);
            }
          fprintf (output, "%d\n", 1 + find_best (t, nb_functions));

          if (param.logarithmic_scale_x == 0)
            {
              mpfr_add (x, x, incr_x, MPFR_RNDU);
              if (mpfr_cmp_d (x, param.max_x) > 0)
                test=0;
            }
          else
            {
              if (mpfr_sgn (x) < 0 )
                { /* if x<0, it means that logarithmic_scale_x=-1 */
                  mpfr_div (x, x, incr_x, MPFR_RNDU);
                  mpfr_abs (temp, x, MPFR_RNDD);
                  mpfr_log2 (temp, temp, MPFR_RNDD);
                  if (mpfr_cmp_d (temp, param.min_x) < 0)
                    mpfr_neg (x, x, MPFR_RNDN);
                }
              else
                {
                  mpfr_mul (x, x, incr_x, MPFR_RNDU);
                  mpfr_set (temp, x, MPFR_RNDD);
                  mpfr_log2 (temp, temp, MPFR_RNDD);
                  if (mpfr_cmp_d (temp, param.max_x) > 0)
                    test=0;
                }
            }
        }

      prec = ( (param.logarithmic_scale_prec) ? (prec * incr_prec)
               : (prec + incr_prec) );
      fprintf (output, "\n");
    }

  free (t);
  mpfr_clear (incr_x);
  mpfr_clear (x);
  mpfr_clear (x2);
  mpfr_clear (temp);

  return;
}
Exemple #21
0
int
main (void)
{
    mpfr_t  x;

    tests_start_mpfr ();

    mpfr_init (x);

    /* check +infinity gives non-zero for mpfr_inf_p only */
    mpfr_set_ui (x, 1L, MPFR_RNDZ);
    mpfr_div_ui (x, x, 0L, MPFR_RNDZ);
    if (mpfr_nan_p (x) || (mpfr_nan_p) (x) )
    {
        printf ("Error: mpfr_nan_p(+Inf) gives non-zero\n");
        exit (1);
    }
    if (mpfr_inf_p (x) == 0)
    {
        printf ("Error: mpfr_inf_p(+Inf) gives zero\n");
        exit (1);
    }
    if (mpfr_number_p (x) || (mpfr_number_p) (x) )
    {
        printf ("Error: mpfr_number_p(+Inf) gives non-zero\n");
        exit (1);
    }
    if (mpfr_zero_p (x) || (mpfr_zero_p) (x) )
    {
        printf ("Error: mpfr_zero_p(+Inf) gives non-zero\n");
        exit (1);
    }
    if (mpfr_regular_p (x) || (mpfr_regular_p) (x) )
    {
        printf ("Error: mpfr_regular_p(+Inf) gives non-zero\n");
        exit (1);
    }

    /* same for -Inf */
    mpfr_neg (x, x, MPFR_RNDN);
    if (mpfr_nan_p (x) || (mpfr_nan_p(x)))
    {
        printf ("Error: mpfr_nan_p(-Inf) gives non-zero\n");
        exit (1);
    }
    if (mpfr_inf_p (x) == 0)
    {
        printf ("Error: mpfr_inf_p(-Inf) gives zero\n");
        exit (1);
    }
    if (mpfr_number_p (x) || (mpfr_number_p)(x) )
    {
        printf ("Error: mpfr_number_p(-Inf) gives non-zero\n");
        exit (1);
    }
    if (mpfr_zero_p (x) || (mpfr_zero_p)(x) )
    {
        printf ("Error: mpfr_zero_p(-Inf) gives non-zero\n");
        exit (1);
    }
    if (mpfr_regular_p (x) || (mpfr_regular_p) (x) )
    {
        printf ("Error: mpfr_regular_p(-Inf) gives non-zero\n");
        exit (1);
    }

    /* same for NaN */
    mpfr_sub (x, x, x, MPFR_RNDN);
    if (mpfr_nan_p (x) == 0)
    {
        printf ("Error: mpfr_nan_p(NaN) gives zero\n");
        exit (1);
    }
    if (mpfr_inf_p (x) || (mpfr_inf_p)(x) )
    {
        printf ("Error: mpfr_inf_p(NaN) gives non-zero\n");
        exit (1);
    }
    if (mpfr_number_p (x) || (mpfr_number_p) (x) )
    {
        printf ("Error: mpfr_number_p(NaN) gives non-zero\n");
        exit (1);
    }
    if (mpfr_zero_p (x) || (mpfr_zero_p)(x) )
    {
        printf ("Error: mpfr_number_p(NaN) gives non-zero\n");
        exit (1);
    }
    if (mpfr_regular_p (x) || (mpfr_regular_p) (x) )
    {
        printf ("Error: mpfr_regular_p(NaN) gives non-zero\n");
        exit (1);
    }

    /* same for a regular number */
    mpfr_set_ui (x, 1, MPFR_RNDN);
    if (mpfr_nan_p (x) || (mpfr_nan_p)(x))
    {
        printf ("Error: mpfr_nan_p(1) gives non-zero\n");
        exit (1);
    }
    if (mpfr_inf_p (x) || (mpfr_inf_p)(x) )
    {
        printf ("Error: mpfr_inf_p(1) gives non-zero\n");
        exit (1);
    }
    if (mpfr_number_p (x) == 0)
    {
        printf ("Error: mpfr_number_p(1) gives zero\n");
        exit (1);
    }
    if (mpfr_zero_p (x) || (mpfr_zero_p) (x) )
    {
        printf ("Error: mpfr_zero_p(1) gives non-zero\n");
        exit (1);
    }
    if (mpfr_regular_p (x) == 0 || (mpfr_regular_p) (x) == 0)
    {
        printf ("Error: mpfr_regular_p(1) gives zero\n");
        exit (1);
    }

    /* Same for +0 */
    mpfr_set_ui (x, 0, MPFR_RNDN);
    if (mpfr_nan_p (x) || (mpfr_nan_p)(x))
    {
        printf ("Error: mpfr_nan_p(+0) gives non-zero\n");
        exit (1);
    }
    if (mpfr_inf_p (x) || (mpfr_inf_p)(x) )
    {
        printf ("Error: mpfr_inf_p(+0) gives non-zero\n");
        exit (1);
    }
    if (mpfr_number_p (x) == 0)
    {
        printf ("Error: mpfr_number_p(+0) gives zero\n");
        exit (1);
    }
    if (mpfr_zero_p (x) == 0 )
    {
        printf ("Error: mpfr_zero_p(+0) gives zero\n");
        exit (1);
    }
    if (mpfr_regular_p (x) || (mpfr_regular_p) (x) )
    {
        printf ("Error: mpfr_regular_p(+0) gives non-zero\n");
        exit (1);
    }

    /* Same for -0 */
    mpfr_set_ui (x, 0, MPFR_RNDN);
    mpfr_neg (x, x, MPFR_RNDN);
    if (mpfr_nan_p (x) || (mpfr_nan_p)(x))
    {
        printf ("Error: mpfr_nan_p(-0) gives non-zero\n");
        exit (1);
    }
    if (mpfr_inf_p (x) || (mpfr_inf_p)(x) )
    {
        printf ("Error: mpfr_inf_p(-0) gives non-zero\n");
        exit (1);
    }
    if (mpfr_number_p (x) == 0)
    {
        printf ("Error: mpfr_number_p(-0) gives zero\n");
        exit (1);
    }
    if (mpfr_zero_p (x) == 0 )
    {
        printf ("Error: mpfr_zero_p(-0) gives zero\n");
        exit (1);
    }
    if (mpfr_regular_p (x) || (mpfr_regular_p) (x) )
    {
        printf ("Error: mpfr_regular_p(-0) gives non-zero\n");
        exit (1);
    }

    mpfr_clear (x);

    tests_end_mpfr ();
    return 0;
}
Exemple #22
0
int
main (int argc, char *argv[])
{
  mpfr_t x;
  unsigned int i;
  unsigned int prec[10] = {14, 15, 19, 22, 23, 24, 25, 40, 41, 52};
  unsigned int prec2[10] = {4, 5, 6, 19, 70, 95, 100, 106, 107, 108};

  tests_start_mpfr ();

  check_nans ();

  mpfr_init (x);

  mpfr_set_prec (x, 2);
  mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
  mpfr_tan (x, x, MPFR_RNDD);
  if (mpfr_cmp_ui_2exp(x, 1, -1))
    {
      printf ("mpfr_tan(0.5, MPFR_RNDD) failed\n"
              "expected 0.5, got");
      mpfr_print_binary(x);
      putchar('\n');
      exit (1);
    }

  /* check that tan(3*Pi/4) ~ -1 */
  for (i=0; i<10; i++)
    {
      mpfr_set_prec (x, prec[i]);
      mpfr_const_pi (x, MPFR_RNDN);
      mpfr_mul_ui (x, x, 3, MPFR_RNDN);
      mpfr_div_ui (x, x, 4, MPFR_RNDN);
      mpfr_tan (x, x, MPFR_RNDN);
      if (mpfr_cmp_si (x, -1))
        {
          printf ("tan(3*Pi/4) fails for prec=%u\n", prec[i]);
          exit (1);
        }
    }

  /* check that tan(7*Pi/4) ~ -1 */
  for (i=0; i<10; i++)
    {
      mpfr_set_prec (x, prec2[i]);
      mpfr_const_pi (x, MPFR_RNDN);
      mpfr_mul_ui (x, x, 7, MPFR_RNDN);
      mpfr_div_ui (x, x, 4, MPFR_RNDN);
      mpfr_tan (x, x, MPFR_RNDN);
      if (mpfr_cmp_si (x, -1))
        {
          printf ("tan(3*Pi/4) fails for prec=%u\n", prec2[i]);
          exit (1);
        }
    }

  mpfr_clear (x);

  test_generic (2, 100, 10);

  data_check ("data/tan", mpfr_tan, "mpfr_tan");
  bad_cases (mpfr_tan, mpfr_atan, "mpfr_tan", 256, -256, 255, 4, 128, 800, 40);

  tests_end_mpfr ();
  return 0;
}
Exemple #23
0
static void
special (void)
{
  mpfr_t x, y;
  unsigned xprec, yprec;

  mpfr_init (x);
  mpfr_init (y);

  mpfr_set_prec (x, 32);
  mpfr_set_prec (y, 32);
  mpfr_set_ui (x, 1, MPFR_RNDN);
  mpfr_div_ui (y, x, 3, MPFR_RNDN);

  mpfr_set_prec (x, 100);
  mpfr_set_prec (y, 100);
  mpfr_urandomb (x, RANDS);
  mpfr_div_ui (y, x, 123456, MPFR_RNDN);
  mpfr_set_ui (x, 0, MPFR_RNDN);
  mpfr_div_ui (y, x, 123456789, MPFR_RNDN);
  if (mpfr_cmp_ui (y, 0))
    {
      printf ("mpfr_div_ui gives non-zero for 0/ui\n");
      exit (1);
    }

  /* bug found by Norbert Mueller, 21 Aug 2001 */
  mpfr_set_prec (x, 110);
  mpfr_set_prec (y, 60);
  mpfr_set_str_binary (x, "0.110101110011111110011111001110011001110111000000111110001000111011000011E-44");
  mpfr_div_ui (y, x, 17, MPFR_RNDN);
  mpfr_set_str_binary (x, "0.11001010100101100011101110000001100001010110101001010011011E-48");
  if (mpfr_cmp (x, y))
    {
      printf ("Error in x/17 for x=1/16!\n");
      printf ("Expected ");
      mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
      printf ("\nGot      ");
      mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
      printf ("\n");
      exit (1);
    }

  /* corner case */
  mpfr_set_prec (x, 2 * mp_bits_per_limb);
  mpfr_set_prec (y, 2);
  mpfr_set_ui (x, 4, MPFR_RNDN);
  mpfr_nextabove (x);
  mpfr_div_ui (y, x, 2, MPFR_RNDN); /* exactly in the middle */
  MPFR_ASSERTN(mpfr_cmp_ui (y, 2) == 0);

  mpfr_set_prec (x, 3 * mp_bits_per_limb);
  mpfr_set_prec (y, 2);
  mpfr_set_ui (x, 2, MPFR_RNDN);
  mpfr_nextabove (x);
  mpfr_div_ui (y, x, 2, MPFR_RNDN);
  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0);

  mpfr_set_prec (x, 3 * mp_bits_per_limb);
  mpfr_set_prec (y, 2);
  mpfr_set_si (x, -4, MPFR_RNDN);
  mpfr_nextbelow (x);
  mpfr_div_ui (y, x, 2, MPFR_RNDD);
  MPFR_ASSERTN(mpfr_cmp_si (y, -3) == 0);

  for (xprec = 53; xprec <= 128; xprec++)
    {
      mpfr_set_prec (x, xprec);
      mpfr_set_str_binary (x, "0.1100100100001111110011111000000011011100001100110111E2");
      for (yprec = 53; yprec <= 128; yprec++)
        {
          mpfr_set_prec (y, yprec);
          mpfr_div_ui (y, x, 1, MPFR_RNDN);
          if (mpfr_cmp(x,y))
            {
              printf ("division by 1.0 fails for xprec=%u, yprec=%u\n", xprec, yprec);
              printf ("expected "); mpfr_print_binary (x); puts ("");
              printf ("got      "); mpfr_print_binary (y); puts ("");
              exit (1);
            }
        }
    }

  /* Bug reported by Mark Dickinson, 6 Nov 2007 */
  mpfr_set_si (x, 0, MPFR_RNDN);
  mpfr_set_si (y, -1, MPFR_RNDN);
  mpfr_div_ui (y, x, 4, MPFR_RNDN);
  MPFR_ASSERTN(MPFR_IS_ZERO(y) && MPFR_IS_POS(y));

  mpfr_clear (x);
  mpfr_clear (y);
}
Exemple #24
0
int main (int argc, char *argv[]){

	mpfr_t *lambda, *kappa;
	
	char f_out_name[BUFSIZ];
	int d,iters,n, k, nk,nf,na,nb;
	double *lambdas, *kappas, *f,*a,*b;
		
	param_file_type param[Nparam] = 
    {{"d:"     , "%d", &d,       NULL, sizeof(int)},
     {"iter:"  , "%d", &iters,   NULL, sizeof(int)},
	 {"lambda:", "DATA_FILE", &lambdas, &n , sizeof(double)},
	 {"kappa:", "DATA_FILE", &kappas, &nk , sizeof(double)},  /*psi*/
	 {"h:", "DATA_FILE", &f, &nf , sizeof(double)},           /*odf*/
	 {"a:", "DATA_FILE", &a, &na , sizeof(double)},          /*pdf a*/
	 {"bc:", "DATA_FILE", &b, &nb , sizeof(double)},          /*pdf sqrt(b^2 + c^2)*/
	 {"res1:","%s ", &f_out_name,NULL, 0}};
    
	FILE *f_param;
	FILE *f_out;

	if (argc<2) {
		printf("Error! Missing parameter - parameter_file.\n");
		printf("%s\n",argv[0]);
		abort();
	}
	  
	/* read parameter file */
	f_param = check_fopen(argv[1],"r");
	if (read_param_file(f_param,param,Nparam,argc==2)<Nparam){	
		/*printf("Some parameters not found!");*/
		/*abort();*/
	}
	fclose(f_param);
	
	/* precission & delta */
	init_prec(d);
	
	long int prec = d;
	
	
	if (nk>0) {   /* kappas given*/
		mpfr_t C;
		
		kappa = (mpfr_t*) malloc (nk*sizeof(mpfr_t));
		
		for(k=0;k<nk;k++){ 
			mpfr_init2(kappa[k],prec);
			mpfr_init_set_d(kappa[k], kappas[k],prec);
		}
		
		mhyper(C, kappa, nk);
		
		/* gmp_printf("C: %.*Fe \n ", 20, C);	*/
		
		if (nf>0) /* eval odf values*/
		{
			eval_exp_Ah(C,f,nf);
			
			f_out = check_fopen(f_out_name,"wb");
			fwrite(f,sizeof(double),nf,f_out);
			fclose(f_out);
		} 
		if ( na > 0) {/* eval pdf values*/
		
		/* testing BesselI[0,a]
			mpfr_t in, out;					
						
			for(k=0;k<na;k++){
			
				mpfr_init2(in, prec);
				mpfr_set_d(in,	a[k],prec);
				mpfr_init2(out, prec);
				
				mpfr_i0(out, in, prec);
				
				
				mpfr_printf ("%.1028RNf\ndd", out);
				
				a[k] = mpfr_get_d(out,prec);
				
			}
				
			f_out = check_fopen(f_out_name,"wb");
			fwrite(a,sizeof(double),na,f_out);
			fclose(f_out);
		*/
		
			
			eval_exp_besseli(a,b,C,na);
				
			f_out = check_fopen(f_out_name,"wb");
			fwrite(a,sizeof(double),na,f_out);
			fclose(f_out);
		}
		
		if (nf == 0 && na == 0) { /* only return constant */
	
			double CC = mpfr_get_d(C,prec);
			
			f_out = check_fopen(f_out_name,"wb");
			fwrite(&CC,sizeof(double),1,f_out);
			fclose(f_out);
		
		}
	
	} else {	/* solve kappas */
		/* copy input variables */	
		lambda = (mpfr_t*) malloc (n*sizeof(mpfr_t));
		kappa = (mpfr_t*) malloc (n*sizeof(mpfr_t));	
		
		for(k=0;k<n;k++){ 
				mpfr_init_set_ui(kappa[k],0,prec);
				mpfr_init_set_d(lambda[k],lambdas[k],prec);
			}
			
				
		if(iters>0){		
			/* check input */
			mpfr_t tmp;
			mpfr_init(tmp);
			mpfr_set_d(tmp,0,prec);
			
			for(k=0;k<n;k++){
				mpfr_add(tmp,tmp,lambda[k],prec);
			}
			
			mpfr_ui_sub(tmp,1,tmp,prec);
			mpfr_div_ui(tmp,tmp,n,prec);
			
			for(k=0;k<n;k++){ 		
				mpfr_add(lambda[k],lambda[k],tmp,prec);
			}
			
			mpfr_init2(tmp,prec);
			for(k=0;k<n;k++){
				mpfr_add(tmp,tmp,lambda[k],prec);
			}
			
			mpfr_init2(tmp,prec);
			if( mpfr_cmp(lambda[min_N(lambda,n)],tmp) < 0 ){
				printf("not well formed! sum should be exactly 1 and no lambda negativ");
				exit(0);
			}
			
			
			/* solve the problem */	
			newton(iters,kappa, lambda, n);

		} else {
			guessinitial(kappa, lambda, n);
		}
		
				
		for(k=0;k<n;k++){
			lambdas[k] = mpfr_get_d(kappa[k],GMP_RNDN);	/* something wents wront in matlab for 473.66316276431799;*/
								/* % bug:   lambda= [0.97 0.01 0.001];*/
		}
			
		f_out = check_fopen(f_out_name,"wb");
		fwrite(lambdas,sizeof(double),n,f_out);
		fclose(f_out);
		
		free_N(lambda,n);
		free_N(kappa,n);
		
	}
	
	
	

	
  
	return EXIT_SUCCESS;
}
Exemple #25
0
int main(int argc, char **argv) {
    mpfr_t tmp1;
    mpfr_t tmp2;
    mpfr_t tmp3;
    mpfr_t s1;
    mpfr_t s2;
    mpfr_t r;
    mpfr_t a1;
    mpfr_t a2;

    time_t start_time;
    time_t end_time;

    // Parse command line opts
    int hide_pi = 0;
    if(argc == 2) {
        if(strcmp(argv[1], "--hide-pi") == 0) {
            hide_pi = 1;
        } else if((precision = atoi(argv[1])) == 0) {
            fprintf(stderr, "Invalid precision specified. Aborting.\n");
            return 1;
        }
    } else if(argc == 3) {
        if(strcmp(argv[1], "--hide-pi") == 0) {
            hide_pi = 1;
        }

        if((precision = atoi(argv[2])) == 0) {
            fprintf(stderr, "Invalid precision specified. Aborting.\n");
            return 1;
        }
    }

    // If the precision was not specified, default it
    if(precision == 0) {
        precision = DEFAULT_PRECISION;
    }


    // Actual number of correct digits is roughly 3.35 times the requested precision
    precision *= 3.35;

    mpfr_set_default_prec(precision);

    mpfr_inits(tmp1, tmp2, tmp3, s1, s2, r, a1, a2, NULL);

    start_time = time(NULL);

    // a0 = 1/3
    mpfr_set_ui(a1, 1, MPFR_RNDN);
    mpfr_div_ui(a1, a1, 3, MPFR_RNDN);

    // s0 = (3^.5 - 1) / 2
    mpfr_sqrt_ui(s1, 3, MPFR_RNDN);
    mpfr_sub_ui(s1, s1, 1, MPFR_RNDN);
    mpfr_div_ui(s1, s1, 2, MPFR_RNDN);

    unsigned long i = 0;
    while(i < MAX_ITERS) {
        // r = 3 / (1 + 2(1-s^3)^(1/3))
        mpfr_pow_ui(tmp1, s1, 3, MPFR_RNDN);
        mpfr_ui_sub(r, 1, tmp1, MPFR_RNDN);
        mpfr_root(r, r, 3, MPFR_RNDN);
        mpfr_mul_ui(r, r, 2, MPFR_RNDN);
        mpfr_add_ui(r, r, 1, MPFR_RNDN);
        mpfr_ui_div(r, 3, r, MPFR_RNDN);

        // s = (r - 1) / 2
        mpfr_sub_ui(s2, r, 1, MPFR_RNDN);
        mpfr_div_ui(s2, s2, 2, MPFR_RNDN);

        // a = r^2 * a - 3^i(r^2-1)
        mpfr_pow_ui(tmp1, r, 2, MPFR_RNDN);
        mpfr_mul(a2, tmp1, a1, MPFR_RNDN);
        mpfr_sub_ui(tmp1, tmp1, 1, MPFR_RNDN);
        mpfr_ui_pow_ui(tmp2, 3UL, i, MPFR_RNDN);
        mpfr_mul(tmp1, tmp1, tmp2, MPFR_RNDN);        
        mpfr_sub(a2, a2, tmp1, MPFR_RNDN);
        
        // s1 = s2
        mpfr_set(s1, s2, MPFR_RNDN);
        // a1 = a2
        mpfr_set(a1, a2, MPFR_RNDN);

        i++;
    }

    // pi = 1/a
    mpfr_ui_div(a2, 1, a2, MPFR_RNDN);

    end_time = time(NULL);

    mpfr_clears(tmp1, tmp2, tmp3, s1, s2, r, a1, NULL);

    // Write the digits to a string for accuracy comparison
    char *pi = malloc(precision + 100);
    if(pi == NULL) {
        fprintf(stderr, "Failed to allocated memory for output string.\n");
        return 1;
    }

    mpfr_sprintf(pi, "%.*R*f", precision, MPFR_RNDN, a2);

    // Check out accurate we are
    unsigned long accuracy = check_digits(pi);

    // Print the results (only print the digits that are accurate)
    if(!hide_pi) {
        // Plus two for the "3." at the beginning
        for(unsigned long i=0; i<(unsigned long)(precision/3.35)+2; i++) {
            printf("%c", pi[i]);
        }
        printf("\n");
    }    // Send the time and accuracy to stderr so pi can be redirected to a file if necessary
    fprintf(stderr, "Time: %d seconds\nAccuracy: %lu digits\n", (int)(end_time - start_time), accuracy);

    mpfr_clear(a2);
    free(pi);
    pi = NULL;

    return 0;
}
Exemple #26
0
static int
mpfr_all_div (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t r)
{
  mpfr_t a2;
  unsigned int oldflags, newflags;
  int inex, inex2;

  oldflags = __gmpfr_flags;
  inex = mpfr_div (a, b, c, r);

  if (a == b || a == c)
    return inex;

  newflags = __gmpfr_flags;

  mpfr_init2 (a2, MPFR_PREC (a));

  if (mpfr_integer_p (b) && ! (MPFR_IS_ZERO (b) && MPFR_IS_NEG (b)))
    {
      /* b is an integer, but not -0 (-0 is rejected as
         it becomes +0 when converted to an integer). */
      if (mpfr_fits_ulong_p (b, MPFR_RNDA))
        {
          __gmpfr_flags = oldflags;
          inex2 = mpfr_ui_div (a2, mpfr_get_ui (b, MPFR_RNDN), c, r);
          MPFR_ASSERTN (SAME_SIGN (inex2, inex));
          MPFR_ASSERTN (__gmpfr_flags == newflags);
          check_equal (a, a2, "mpfr_ui_div", b, c, r);
        }
      if (mpfr_fits_slong_p (b, MPFR_RNDA))
        {
          __gmpfr_flags = oldflags;
          inex2 = mpfr_si_div (a2, mpfr_get_si (b, MPFR_RNDN), c, r);
          MPFR_ASSERTN (SAME_SIGN (inex2, inex));
          MPFR_ASSERTN (__gmpfr_flags == newflags);
          check_equal (a, a2, "mpfr_si_div", b, c, r);
        }
    }

  if (mpfr_integer_p (c) && ! (MPFR_IS_ZERO (c) && MPFR_IS_NEG (c)))
    {
      /* c is an integer, but not -0 (-0 is rejected as
         it becomes +0 when converted to an integer). */
      if (mpfr_fits_ulong_p (c, MPFR_RNDA))
        {
          __gmpfr_flags = oldflags;
          inex2 = mpfr_div_ui (a2, b, mpfr_get_ui (c, MPFR_RNDN), r);
          MPFR_ASSERTN (SAME_SIGN (inex2, inex));
          MPFR_ASSERTN (__gmpfr_flags == newflags);
          check_equal (a, a2, "mpfr_div_ui", b, c, r);
        }
      if (mpfr_fits_slong_p (c, MPFR_RNDA))
        {
          __gmpfr_flags = oldflags;
          inex2 = mpfr_div_si (a2, b, mpfr_get_si (c, MPFR_RNDN), r);
          MPFR_ASSERTN (SAME_SIGN (inex2, inex));
          MPFR_ASSERTN (__gmpfr_flags == newflags);
          check_equal (a, a2, "mpfr_div_si", b, c, r);
        }
    }

  mpfr_clear (a2);

  return inex;
}
Exemple #27
0
/* Put in s an approximation of digamma(x).
   Assumes x >= 2.
   Assumes s does not overlap with x.
   Returns an integer e such that the error is bounded by 2^e ulps
   of the result s.
*/
static mpfr_exp_t
mpfr_digamma_approx (mpfr_ptr s, mpfr_srcptr x)
{
  mpfr_prec_t p = MPFR_PREC (s);
  mpfr_t t, u, invxx;
  mpfr_exp_t e, exps, f, expu;
  mpz_t *INITIALIZED(B);  /* variable B declared as initialized */
  unsigned long n0, n; /* number of allocated B[] */

  MPFR_ASSERTN(MPFR_IS_POS(x) && (MPFR_EXP(x) >= 2));

  mpfr_init2 (t, p);
  mpfr_init2 (u, p);
  mpfr_init2 (invxx, p);

  mpfr_log (s, x, MPFR_RNDN);         /* error <= 1/2 ulp */
  mpfr_ui_div (t, 1, x, MPFR_RNDN);   /* error <= 1/2 ulp */
  mpfr_div_2exp (t, t, 1, MPFR_RNDN); /* exact */
  mpfr_sub (s, s, t, MPFR_RNDN);
  /* error <= 1/2 + 1/2*2^(EXP(olds)-EXP(s)) + 1/2*2^(EXP(t)-EXP(s)).
     For x >= 2, log(x) >= 2*(1/(2x)), thus olds >= 2t, and olds - t >= olds/2,
     thus 0 <= EXP(olds)-EXP(s) <= 1, and EXP(t)-EXP(s) <= 0, thus
     error <= 1/2 + 1/2*2 + 1/2 <= 2 ulps. */
  e = 2; /* initial error */
  mpfr_mul (invxx, x, x, MPFR_RNDZ);     /* invxx = x^2 * (1 + theta)
                                            for |theta| <= 2^(-p) */
  mpfr_ui_div (invxx, 1, invxx, MPFR_RNDU); /* invxx = 1/x^2 * (1 + theta)^2 */

  /* in the following we note err=xxx when the ratio between the approximation
     and the exact result can be written (1 + theta)^xxx for |theta| <= 2^(-p),
     following Higham's method */
  B = mpfr_bernoulli_internal ((mpz_t *) 0, 0);
  mpfr_set_ui (t, 1, MPFR_RNDN); /* err = 0 */
  for (n = 1;; n++)
    {
      /* compute next Bernoulli number */
      B = mpfr_bernoulli_internal (B, n);
      /* The main term is Bernoulli[2n]/(2n)/x^(2n) = B[n]/(2n+1)!(2n)/x^(2n)
         = B[n]*t[n]/(2n) where t[n]/t[n-1] = 1/(2n)/(2n+1)/x^2. */
      mpfr_mul (t, t, invxx, MPFR_RNDU);        /* err = err + 3 */
      mpfr_div_ui (t, t, 2 * n, MPFR_RNDU);     /* err = err + 1 */
      mpfr_div_ui (t, t, 2 * n + 1, MPFR_RNDU); /* err = err + 1 */
      /* we thus have err = 5n here */
      mpfr_div_ui (u, t, 2 * n, MPFR_RNDU);     /* err = 5n+1 */
      mpfr_mul_z (u, u, B[n], MPFR_RNDU);       /* err = 5n+2, and the
                                                   absolute error is bounded
                                                   by 10n+4 ulp(u) [Rule 11] */
      /* if the terms 'u' are decreasing by a factor two at least,
         then the error coming from those is bounded by
         sum((10n+4)/2^n, n=1..infinity) = 24 */
      exps = mpfr_get_exp (s);
      expu = mpfr_get_exp (u);
      if (expu < exps - (mpfr_exp_t) p)
        break;
      mpfr_sub (s, s, u, MPFR_RNDN); /* error <= 24 + n/2 */
      if (mpfr_get_exp (s) < exps)
        e <<= exps - mpfr_get_exp (s);
      e ++; /* error in mpfr_sub */
      f = 10 * n + 4;
      while (expu < exps)
        {
          f = (1 + f) / 2;
          expu ++;
        }
      e += f; /* total rouding error coming from 'u' term */
    }

  n0 = ++n;
  while (n--)
    mpz_clear (B[n]);
  (*__gmp_free_func) (B, n0 * sizeof (mpz_t));

  mpfr_clear (t);
  mpfr_clear (u);
  mpfr_clear (invxx);

  f = 0;
  while (e > 1)
    {
      f++;
      e = (e + 1) / 2;
      /* Invariant: 2^f * e does not decrease */
    }
  return f;
}
Exemple #28
0
Fichier : yn.c Projet : Kirija/XPIR
/* compute in s an approximation of
   S3 = c*sum((h(k)+h(n+k))*y^k/k!/(n+k)!,k=0..infinity)
   where h(k) = 1 + 1/2 + ... + 1/k
   k=0: h(n)
   k=1: 1+h(n+1)
   k=2: 3/2+h(n+2)
   Returns e such that the error is bounded by 2^e ulp(s).
*/
static mpfr_exp_t
mpfr_yn_s3 (mpfr_ptr s, mpfr_srcptr y, mpfr_srcptr c, unsigned long n)
{
  unsigned long k, zz;
  mpfr_t t, u;
  mpz_t p, q; /* p/q will store h(k)+h(n+k) */
  mpfr_exp_t exps, expU;

  zz = mpfr_get_ui (y, MPFR_RNDU); /* y = z^2/4 */
  MPFR_ASSERTN (zz < ULONG_MAX - 2);
  zz += 2; /* z^2 <= 2^zz */
  mpz_init_set_ui (p, 0);
  mpz_init_set_ui (q, 1);
  /* initialize p/q to h(n) */
  for (k = 1; k <= n; k++)
    {
      /* p/q + 1/k = (k*p+q)/(q*k) */
      mpz_mul_ui (p, p, k);
      mpz_add (p, p, q);
      mpz_mul_ui (q, q, k);
    }
  mpfr_init2 (t, MPFR_PREC(s));
  mpfr_init2 (u, MPFR_PREC(s));
  mpfr_fac_ui (t, n, MPFR_RNDN);
  mpfr_div (t, c, t, MPFR_RNDN);    /* c/n! */
  mpfr_mul_z (u, t, p, MPFR_RNDN);
  mpfr_div_z (s, u, q, MPFR_RNDN);
  exps = MPFR_EXP (s);
  expU = exps;
  for (k = 1; ;k ++)
    {
      /* update t */
      mpfr_mul (t, t, y, MPFR_RNDN);
      mpfr_div_ui (t, t, k, MPFR_RNDN);
      mpfr_div_ui (t, t, n + k, MPFR_RNDN);
      /* update p/q:
         p/q + 1/k + 1/(n+k) = [p*k*(n+k) + q*(n+k) + q*k]/(q*k*(n+k)) */
      mpz_mul_ui (p, p, k);
      mpz_mul_ui (p, p, n + k);
      mpz_addmul_ui (p, q, n + 2 * k);
      mpz_mul_ui (q, q, k);
      mpz_mul_ui (q, q, n + k);
      mpfr_mul_z (u, t, p, MPFR_RNDN);
      mpfr_div_z (u, u, q, MPFR_RNDN);
      exps = MPFR_EXP (u);
      if (exps > expU)
        expU = exps;
      mpfr_add (s, s, u, MPFR_RNDN);
      exps = MPFR_EXP (s);
      if (exps > expU)
        expU = exps;
      if (MPFR_EXP (u) + (mpfr_exp_t) MPFR_PREC (u) < MPFR_EXP (s) &&
          zz / (2 * k) < k + n)
        break;
    }
  mpfr_clear (t);
  mpfr_clear (u);
  mpz_clear (p);
  mpz_clear (q);
  exps = expU - MPFR_EXP (s);
  /* the error is bounded by (6k^2+33/2k+11) 2^exps ulps
     <= 8*(k+2)^2 2^exps ulps */
  return 3 + 2 * MPFR_INT_CEIL_LOG2(k + 2) + exps;
}
Exemple #29
0
int
main (void)
{
  mpfr_prec_t prec;
  mpfr_t x, y;
  intmax_t s;
  uintmax_t u;

  tests_start_mpfr ();

  for (u = MPFR_UINTMAX_MAX, prec = 0; u != 0; u /= 2, prec++)
    { }

  mpfr_init2 (x, prec + 4);
  mpfr_init2 (y, prec + 4);

  mpfr_set_ui (x, 0, MPFR_RNDN);
  check_sj (0, x);
  check_uj (0, x);

  mpfr_set_ui (x, 1, MPFR_RNDN);
  check_sj (1, x);
  check_uj (1, x);

  mpfr_neg (x, x, MPFR_RNDN);
  check_sj (-1, x);

  mpfr_set_si_2exp (x, 1, prec, MPFR_RNDN);
  mpfr_sub_ui (x, x, 1, MPFR_RNDN); /* UINTMAX_MAX */

  mpfr_div_ui (y, x, 2, MPFR_RNDZ);
  mpfr_trunc (y, y); /* INTMAX_MAX */
  for (s = MPFR_INTMAX_MAX; s != 0; s /= 17)
    {
      check_sj (s, y);
      mpfr_div_ui (y, y, 17, MPFR_RNDZ);
      mpfr_trunc (y, y);
    }

  mpfr_div_ui (y, x, 2, MPFR_RNDZ);
  mpfr_trunc (y, y); /* INTMAX_MAX */
  mpfr_neg (y, y, MPFR_RNDN);
  if (MPFR_INTMAX_MIN + MPFR_INTMAX_MAX != 0)
    mpfr_sub_ui (y, y, 1, MPFR_RNDN); /* INTMAX_MIN */
  for (s = MPFR_INTMAX_MIN; s != 0; s /= 17)
    {
      check_sj (s, y);
      mpfr_div_ui (y, y, 17, MPFR_RNDZ);
      mpfr_trunc (y, y);
    }

  for (u = MPFR_UINTMAX_MAX; u != 0; u /= 17)
    {
      check_uj (u, x);
      mpfr_div_ui (x, x, 17, MPFR_RNDZ);
      mpfr_trunc (x, x);
    }

  mpfr_clear (x);
  mpfr_clear (y);

  check_erange ();

  tests_end_mpfr ();
  return 0;
}
Exemple #30
0
static void
test_grandom (long nbtests, mpfr_prec_t prec, mpfr_rnd_t rnd,
              int verbose)
{
  mpfr_t *t;
  mpfr_t av, va, tmp;
  int i, inexact;

  nbtests = (nbtests & 1) ? (nbtests + 1) : nbtests;
  t = (mpfr_t *) malloc (nbtests * sizeof (mpfr_t));
  if (t == NULL)
    {
      fprintf (stderr, "tgrandom: can't allocate memory in test_grandom\n");
      exit (1);
    }

  for (i = 0; i < nbtests; ++i)
    mpfr_init2 (t[i], prec);

  for (i = 0; i < nbtests; i += 2)
    {
      inexact = mpfr_grandom (t[i], t[i + 1], RANDS, MPFR_RNDN);
      if ((inexact & 3) == 0 || (inexact & (3 << 2)) == 0)
        {
          /* one call in the loop pretended to return an exact number! */
          printf ("Error: mpfr_grandom() returns a zero ternary value.\n");
          exit (1);
        }
    }

#ifdef HAVE_STDARG
  if (verbose)
    {
      mpfr_init2 (av, prec);
      mpfr_init2 (va, prec);
      mpfr_init2 (tmp, prec);

      mpfr_set_ui (av, 0, MPFR_RNDN);
      mpfr_set_ui (va, 0, MPFR_RNDN);
      for (i = 0; i < nbtests; ++i)
        {
          mpfr_add (av, av, t[i], MPFR_RNDN);
          mpfr_sqr (tmp, t[i], MPFR_RNDN);
          mpfr_add (va, va, tmp, MPFR_RNDN);
        }
      mpfr_div_ui (av, av, nbtests, MPFR_RNDN);
      mpfr_div_ui (va, va, nbtests, MPFR_RNDN);
      mpfr_sqr (tmp, av, MPFR_RNDN);
      mpfr_sub (va, va, av, MPFR_RNDN);

      mpfr_printf ("Average = %.5Rf\nVariance = %.5Rf\n", av, va);
      mpfr_clear (av);
      mpfr_clear (va);
      mpfr_clear (tmp);
    }
#endif /* HAVE_STDARG */

  for (i = 0; i < nbtests; ++i)
    mpfr_clear (t[i]);
  free (t);
  return;
}