tidy up float conversion functions

doc/source/fmpr.rst

@@ -192,6 +192,10 @@ Assignment, rounding and conversions
 
     Sets *x* to the exact value of the MPFR variable *y*.
 
+.. function:: double fmpr_get_d(const fmpr_t x, fmpr_rnd_t rnd)
+
+    Returns *x* rounded to a *double* in the direction specified by *rnd*.
+
 .. function:: void fmpr_set_ui(fmpr_t x, ulong c)
 
 .. function:: void fmpr_set_si(fmpr_t x, long c)

fmpr.h

@@ -41,6 +41,15 @@
 #define FMPR_RND_DOWN 3
 #define FMPR_RND_NEAR 4
 
+static __inline__ mpfr_rnd_t rnd_to_mpfr(fmpr_rnd_t rnd)
+{
+    if (rnd == FMPR_RND_DOWN) return MPFR_RNDZ;
+    else if (rnd == FMPR_RND_UP) return MPFR_RNDA;
+    else if (rnd == FMPR_RND_FLOOR) return MPFR_RNDD;
+    else if (rnd == FMPR_RND_CEIL) return MPFR_RNDU;
+    else return MPFR_RNDN;
+}
+
 typedef struct
 {
     fmpz man;
@@ -277,59 +286,11 @@ void fmpr_randtest_not_zero(fmpr_t x, flint_rand_t state, long bits, long exp_bi
 
 void fmpr_randtest_special(fmpr_t x, flint_rand_t state, long bits, long exp_bits);
 
-static __inline__ int
+int fmpr_get_mpfr(mpfr_t x, const fmpr_t y, mpfr_rnd_t rnd);
-fmpr_get_mpfr(mpfr_t x, const fmpr_t y, mpfr_rnd_t rnd)
-{
-    int r;
 
-    if (fmpr_is_special(y))
+void fmpr_set_mpfr(fmpr_t x, const mpfr_t y);
-    {
-        if (fmpr_is_zero(y)) mpfr_set_zero(x, 0);
-        else if (fmpr_is_pos_inf(y)) mpfr_set_inf(x, 1);
-        else if (fmpr_is_neg_inf(y)) mpfr_set_inf(x, -1);
-        else mpfr_set_nan(x);
-        r = 0;
-    }
-    else if (COEFF_IS_MPZ(*fmpr_expref(y)))
-    {
-        printf("exception: exponent too large to convert to mpfr");
-        abort();
-    }
-    else
-    {
-        if (!COEFF_IS_MPZ(*fmpr_manref(y)))
-            r = mpfr_set_si_2exp(x, *fmpr_manref(y), *fmpr_expref(y), rnd);
-        else
-            r = mpfr_set_z_2exp(x, COEFF_TO_PTR(*fmpr_manref(y)), *fmpr_expref(y), rnd);
 
-        if (!mpfr_regular_p(x))
+double fmpr_get_d(const fmpr_t x, fmpr_rnd_t rnd);
-        {
-            printf("exception: exponent too large to convert to mpfr");
-            abort();
-        }
-    }
-
-    return r;
-}
-
-static __inline__ void
-fmpr_set_mpfr(fmpr_t x, const mpfr_t y)
-{
-    if (!mpfr_regular_p(y))
-    {
-        if (mpfr_zero_p(y)) fmpr_zero(x);
-        else if (mpfr_inf_p(y) && mpfr_sgn(y) > 0) fmpr_pos_inf(x);
-        else if (mpfr_inf_p(y) && mpfr_sgn(y) < 0) fmpr_neg_inf(x);
-        else fmpr_nan(x);
-    }
-    else
-    {
-        __mpz_struct * z = _fmpz_promote(fmpr_manref(x));
-        fmpz_set_si(fmpr_expref(x), mpfr_get_z_2exp(z, y));
-        _fmpz_demote_val(fmpr_manref(x));
-        _fmpr_normalise(fmpr_manref(x), fmpr_expref(x), y->_mpfr_prec, FMPR_RND_DOWN);
-    }
-}
 
 static __inline__ void fmpr_set_ui(fmpr_t x, ulong c)
 {
@@ -671,11 +632,7 @@ static __inline__ int fmpr_cmpabs_2exp_si(const fmpr_t x, long e)
     do { \
         mpfr_t __t, __u; \
         mpfr_rnd_t __rnd; \
-        if (rnd == FMPR_RND_DOWN) __rnd = MPFR_RNDZ; \
+        __rnd = rnd_to_mpfr(rnd); \
-        else if (rnd == FMPR_RND_UP) __rnd = MPFR_RNDA; \
-        else if (rnd == FMPR_RND_FLOOR) __rnd = MPFR_RNDD; \
-        else if (rnd == FMPR_RND_CEIL) __rnd = MPFR_RNDU; \
-        else __rnd = MPFR_RNDN; \
         mpfr_init2(__t, 2 + fmpz_bits(fmpr_manref(x))); \
         mpfr_init2(__u, FLINT_MAX(2, prec)); \
         fmpr_get_mpfr(__t, x, MPFR_RNDD); \
@@ -695,11 +652,7 @@ static __inline__ int fmpr_cmpabs_2exp_si(const fmpr_t x, long e)
     do { \
         mpfr_t __t, __u, __v; \
         mpfr_rnd_t __rnd; \
-        if (rnd == FMPR_RND_DOWN) __rnd = MPFR_RNDZ; \
+        __rnd = rnd_to_mpfr(rnd); \
-        else if (rnd == FMPR_RND_UP) __rnd = MPFR_RNDA; \
-        else if (rnd == FMPR_RND_FLOOR) __rnd = MPFR_RNDD; \
-        else if (rnd == FMPR_RND_CEIL) __rnd = MPFR_RNDU; \
-        else __rnd = MPFR_RNDN; \
         mpfr_init2(__t, 2 + fmpz_bits(fmpr_manref(x))); \
         mpfr_init2(__u, FLINT_MAX(2, prec)); \
         mpfr_init2(__v, FLINT_MAX(2, prec)); \

fmpr/get_d.c

@@ -0,0 +1,43 @@
+/*=============================================================================
+
+    This file is part of ARB.
+
+    ARB 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 2 of the License, or
+    (at your option) any later version.
+
+    ARB 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 ARB; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+=============================================================================*/
+/******************************************************************************
+
+    Copyright (C) 2012 Fredrik Johansson
+
+******************************************************************************/
+
+#include "fmpr.h"
+
+double
+fmpr_get_d(const fmpr_t x, fmpr_rnd_t rnd)
+{
+    double r;
+    mpfr_rnd_t mrnd;
+    mpfr_t t;
+
+    mrnd = rnd_to_mpfr(rnd);
+    mpfr_init2(t, 53);
+    fmpr_get_mpfr(t, x, mrnd);
+    r = mpfr_get_d(t, mrnd);
+
+    mpfr_clear(t);
+    return r;
+}
+

fmpr/get_mpfr.c

@@ -0,0 +1,62 @@
+/*=============================================================================
+
+    This file is part of ARB.
+
+    ARB 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 2 of the License, or
+    (at your option) any later version.
+
+    ARB 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 ARB; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+=============================================================================*/
+/******************************************************************************
+
+    Copyright (C) 2012 Fredrik Johansson
+
+******************************************************************************/
+
+#include "fmpr.h"
+
+int
+fmpr_get_mpfr(mpfr_t x, const fmpr_t y, mpfr_rnd_t rnd)
+{
+    int r;
+
+    if (fmpr_is_special(y))
+    {
+        if (fmpr_is_zero(y)) mpfr_set_zero(x, 0);
+        else if (fmpr_is_pos_inf(y)) mpfr_set_inf(x, 1);
+        else if (fmpr_is_neg_inf(y)) mpfr_set_inf(x, -1);
+        else mpfr_set_nan(x);
+        r = 0;
+    }
+    else if (COEFF_IS_MPZ(*fmpr_expref(y)))
+    {
+        printf("exception: exponent too large to convert to mpfr");
+        abort();
+    }
+    else
+    {
+        if (!COEFF_IS_MPZ(*fmpr_manref(y)))
+            r = mpfr_set_si_2exp(x, *fmpr_manref(y), *fmpr_expref(y), rnd);
+        else
+            r = mpfr_set_z_2exp(x, COEFF_TO_PTR(*fmpr_manref(y)), *fmpr_expref(y), rnd);
+
+        if (!mpfr_regular_p(x))
+        {
+            printf("exception: exponent too large to convert to mpfr");
+            abort();
+        }
+    }
+
+    return r;
+}
+

fmpr/set_mpfr.c

@@ -0,0 +1,46 @@
+/*=============================================================================
+
+    This file is part of ARB.
+
+    ARB 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 2 of the License, or
+    (at your option) any later version.
+
+    ARB 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 ARB; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+=============================================================================*/
+/******************************************************************************
+
+    Copyright (C) 2012 Fredrik Johansson
+
+******************************************************************************/
+
+#include "fmpr.h"
+
+void
+fmpr_set_mpfr(fmpr_t x, const mpfr_t y)
+{
+    if (!mpfr_regular_p(y))
+    {
+        if (mpfr_zero_p(y)) fmpr_zero(x);
+        else if (mpfr_inf_p(y) && mpfr_sgn(y) > 0) fmpr_pos_inf(x);
+        else if (mpfr_inf_p(y) && mpfr_sgn(y) < 0) fmpr_neg_inf(x);
+        else fmpr_nan(x);
+    }
+    else
+    {
+        __mpz_struct * z = _fmpz_promote(fmpr_manref(x));
+        fmpz_set_si(fmpr_expref(x), mpfr_get_z_2exp(z, y));
+        _fmpz_demote_val(fmpr_manref(x));
+        _fmpr_normalise(fmpr_manref(x), fmpr_expref(x), y->_mpfr_prec, FMPR_RND_DOWN);
+    }
+}
+

fmprb/gamma.c

@@ -39,18 +39,6 @@ fmprb_stirling_series_coeff(fmprb_t b, ulong k, long prec)
     fmpz_clear(d);
 }
 
-
-double fmpr_get_d(const fmpr_t x)
-{
-    double r;
-    mpfr_t t;
-    mpfr_init2(t, 53);
-    fmpr_get_mpfr(t, x, MPFR_RNDN);
-    r = mpfr_get_d(t, MPFR_RNDN);
-    mpfr_clear(t);
-    return r;
-}
-
 /*
 Heuristic: we use Stirling's series if abs(x) > beta * prec.
 
@@ -63,7 +51,7 @@ argument reduction.
 
 long stirling_choose_r(const fmprb_t x, long wp)
 {
-    double t = fmpr_get_d(fmprb_midref(x));
+    double t = fmpr_get_d(fmprb_midref(x), FMPR_RND_FLOOR);
     double want = FLINT_MAX(5, GAMMA_STIRLING_BETA * wp);
 
     return (long) FLINT_MAX(0, want - t + 1);
@@ -77,7 +65,7 @@ stirling_choose_nterms(const fmprb_t x, long r, double bits)
     double t, logt;
     double mag;
 
-    t = fmpr_get_d(fmprb_midref(x)) + r;
+    t = fmpr_get_d(fmprb_midref(x), FMPR_RND_FLOOR) + r;
     logt = log(t);
 
     for (i = 1; ; i++)
@@ -112,7 +100,7 @@ fmprb_gamma_log_stirling(fmprb_t s, const fmprb_t z, long nterms, long prec)
     {
         fmprb_ui_div(t, 1UL, z, prec);
         fmprb_mul(u, t, t, prec);
-        z_mag = fmpr_get_d(fmprb_midref(w)) * 1.44269504088896;
+        z_mag = fmpr_get_d(fmprb_midref(w), FMPR_RND_UP) * 1.44269504088896;
 
         for (k = nterms - 1; k >= 1; k--)
         {

hypgeom/bound.c

@@ -27,8 +27,6 @@
 #include "double_extras.h"
 #include "hypgeom.h"
 
-double fmpr_get_d(const fmpr_t x);
-
 static __inline__ double d_root(double x, int r)
 {
     if (r == 1)
@@ -124,7 +122,7 @@ long hypgeom_root_bound(const fmpr_t z, int r)
     else
     {
         double zd;
-        zd = fmpr_get_d(z);
+        zd = fmpr_get_d(z, FMPR_RND_UP);
         return d_root(zd, r) + 2;
     }
 }

hypgeom/estimate_terms_d.c

@@ -39,14 +39,12 @@ static __inline__ double d_root(double x, int r)
     return pow(x, 1. / r);
 }
 
-double fmpr_get_d(const fmpr_t x);
-
 long
 hypgeom_estimate_terms(const fmpr_t z, int r, long prec)
 {
     double y, t;
 
-    t = fmpr_get_d(z);
+    t = fmpr_get_d(z, FMPR_RND_UP);
     t = fabs(t);
 
     if (t == 0)