more documentation and test code

This commit is contained in:
Fredrik Johansson 2014-06-20 09:27:47 +02:00
parent 32763c5a2e
commit 9a4b57ec91
6 changed files with 244 additions and 31 deletions

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@ -124,7 +124,7 @@ Computation of single Bernoulli numbers
of the Bernoulli number `B_n`.
This function computes the denominator `d` using von Staudt-Clausen
theorem, numerically approximates `B_n` using :func:`bernoulli_fmprb_ui_zeta`,
theorem, numerically approximates `B_n` using :func:`arb_bernoulli_ui_zeta`,
and then rounds `d B_n` to the correct numerator.
If the working precision is insufficient to determine the numerator,
the function prints a warning message and retries with increased

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@ -137,7 +137,7 @@ Memory management
Error bounding
-------------------------------------------------------------------------------
.. function:: long hypgeom_estimate_terms(const fmpr_t z, int r, long d)
.. function:: long hypgeom_estimate_terms(const mag_t z, int r, long d)
Computes an approximation of the largest `n` such
that `|z|^n/(n!)^r = 2^{-d}`, giving a first-order estimate of the
@ -154,7 +154,7 @@ Error bounding
The function aborts if the computed value of `n` is greater
than or equal to LONG_MAX / 2.
.. function:: long hypgeom_bound(fmpr_t error, int r, long C, long D, long K, const fmpr_t TK, const fmpr_t z, long prec)
.. function:: long hypgeom_bound(mag_t error, int r, long C, long D, long K, const mag_t TK, const mag_t z, long prec)
Computes a truncation parameter sufficient to achieve *prec* bits
of absolute accuracy, according to the strategy described above.
@ -179,13 +179,29 @@ Error bounding
Summation
-------------------------------------------------------------------------------
.. function:: void hypgeom_fmprb_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, const long n, long prec)
.. function:: void fmprb_hypgeom_sum(fmprb_t P, fmprb_t Q, const hypgeom_t hyp, const long n, long prec)
Computes `P, Q` such that `P / Q = \sum_{k=0}^{n-1} T(k)` where `T(k)`
is defined by *hyp*,
using binary splitting and a working precision of *prec* bits.
.. function:: void hypgeom_fmprb_infsum(fmprb_t P, fmprb_t Q, hypgeom_t hyp, long tol, long prec)
.. function:: void fmprb_hypgeom_infsum(fmprb_t P, fmprb_t Q, hypgeom_t hyp, long tol, long prec)
Computes `P, Q` such that `P / Q = \sum_{k=0}^{\infty} T(k)` where `T(k)`
is defined by *hyp*, using binary splitting and
working precision of *prec* bits.
The number of terms is chosen automatically to bound the
truncation error by at most `2^{-\mathrm{tol}}`.
The bound for the truncation error is included in the output
as part of *P*.
.. function:: void arb_hypgeom_sum(arb_t P, arb_t Q, const hypgeom_t hyp, const long n, long prec)
Computes `P, Q` such that `P / Q = \sum_{k=0}^{n-1} T(k)` where `T(k)`
is defined by *hyp*,
using binary splitting and a working precision of *prec* bits.
.. function:: void arb_hypgeom_infsum(arb_t P, arb_t Q, hypgeom_t hyp, long tol, long prec)
Computes `P, Q` such that `P / Q = \sum_{k=0}^{\infty} T(k)` where `T(k)`
is defined by *hyp*, using binary splitting and

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@ -40,10 +40,24 @@ Memory management
.. function:: void mag_init_set(mag_t x, const mag_t y)
Initializes *x* and sets it to the value of *y*.
.. function:: void mag_swap(mag_t x, mag_t y)
Swaps *x* and *y* efficiently.
.. function:: void mag_set(mag_t x, const mag_t y)
Sets *x* to the value of *y*.
.. function:: mag_ptr _mag_vec_init(long n)
Allocates a vector of length *n*. All entries are set to zero.
.. function:: void _mag_vec_clear(mag_ptr v, long n)
Clears a vector of length *n*.
Special values
-------------------------------------------------------------------------------
@ -100,25 +114,57 @@ Arithmetic
.. function:: void mag_mul_2exp_fmpz(mag_t z, const mag_t x, const fmpz_t y)
Sets `z` to `x \times 2^y`. This operation is exact.
Sets *z* to `x \times 2^y`. This operation is exact.
.. function:: void mag_mul(mag_t z, const mag_t x, const mag_t y)
Sets `z` to an upper bound for `xy`.
.. function:: void mag_mul_ui(mag_t z, const mag_t x, ulong y)
.. function:: void mag_mul_fmpz(mag_t z, const mag_t x, const fmpz_t y)
Sets *z* to an upper bound for `xy`.
.. function:: void mag_add(mag_t z, const mag_t x, const mag_t y)
Sets *z* to an upper bound for `x + y`.
.. function:: void mag_addmul(mag_t z, const mag_t x, const mag_t y)
Sets `z` to an upper bound for `z + xy`.
Sets *z* to an upper bound for `z + xy`.
.. function:: void mag_add_2exp_fmpz(mag_t z, const mag_t x, const fmpz_t e)
Sets `z` to an upper bound for `x + 2^e`.
Sets *z* to an upper bound for `x + 2^e`.
.. function:: void mag_div(mag_t z, const mag_t x, const mag_t y)
Sets `z` to an upper bound for `x / y`.
.. function:: void mag_div_ui(mag_t z, const mag_t x, ulong y)
Fast versions
.. function:: void mag_div_fmpz(mag_t z, const mag_t x, const fmpz_t y)
Sets *z* to an upper bound for `x / y`.
.. function:: void mag_mul_lower(mag_t z, const mag_t x, const mag_t y)
.. function:: void mag_mul_ui_lower(mag_t z, const mag_t x, ulong y)
.. function:: void mag_mul_fmpz_lower(mag_t z, const mag_t x, const fmpz_t y)
Sets *z* to a lower bound for `xy`.
.. function:: void mag_add_lower(mag_t z, const mag_t x, const mag_t y)
Sets *z* to a lower bound for `x + y`.
.. function:: void mag_pow_ui(mag_t z, const mag_t x, ulong e)
Sets *z* to an upper bound for `x^e`.
.. function:: void mag_pow_ui_lower(mag_t z, const mag_t x, ulong e)
Sets *z* to a lower bound for `x^e`.
Fast, unsafe versions
-------------------------------------------------------------------------------
The following methods assume that all inputs are finite and that all exponents
@ -140,15 +186,15 @@ as they will be overwritten directly (thus leaking memory).
.. function:: void mag_fast_mul(mag_t z, const mag_t x, const mag_t y)
Sets `z` to an upper bound for `xy`.
Sets *z* to an upper bound for `xy`.
.. function:: void mag_fast_addmul(mag_t z, const mag_t x, const mag_t y)
Sets `z` to an upper bound for `z + xy`.
Sets *z* to an upper bound for `z + xy`.
.. function:: void mag_fast_add_2exp_si(mag_t z, const mag_t x, long e)
Sets `z` to an upper bound for `x + 2^e`.
Sets *z* to an upper bound for `x + 2^e`.
Input and output
-------------------------------------------------------------------------------
@ -172,15 +218,23 @@ Random generation
Conversions
-------------------------------------------------------------------------------
.. function:: void mag_set_d(mag_t y, double x)
.. function:: void mag_set_fmpr(mag_t y, const fmpr_t x)
.. function:: void mag_set_ui(mag_t y, ulong x)
.. function:: void mag_set_fmpz(mag_t y, const fmpz_t x)
Sets *y* to an upper bound for `|x|`.
.. function:: void mag_set_d_2exp_fmpz(mag_t z, double x, const fmpz_t y)
.. function:: void mag_set_fmpz_2exp_fmpz(mag_t z, const fmpz_t x, const fmpz_t y)
Sets *z* to an upper bound for `x \times 2^y`.
.. function:: void mag_set_ui_2exp_si(mag_t z, ulong x, long y)
.. function:: void mag_set_fmpr(mag_t y, const fmpr_t x)
Sets *y* to an upper bound for *x*.
Sets *z* to an upper bound for `|x| \times 2^y`.
.. function:: void mag_get_fmpr(fmpr_t y, const mag_t x)
@ -190,3 +244,34 @@ Conversions
Sets *y* exactly to *x*. Assumes that no overflow occurs.
.. function:: void mag_set_ui_lower(mag_t z, ulong x)
.. function:: void mag_set_fmpz_lower(mag_t z, const fmpz_t x)
Sets *y* to a lower bound for `|x|`.
.. function:: void mag_set_fmpz_2exp_fmpz_lower(mag_t z, const fmpz_t x, const fmpz_t y)
Sets *z* to a lower bound for `|x| \times 2^y`.
Special functions
-------------------------------------------------------------------------------
.. function:: void mag_log1p(mag_t z, const mag_t x)
Sets *z* to an upper bound for `\log(1+x)`. The bound is computed
accurately for small *x*.
.. function:: void mag_fac_ui(mag_t z, ulong n)
Sets *z* to an upper bound for `n!`.
.. function:: void mag_rfac_ui(mag_t z, ulong n)
Sets *z* to an upper bound for `1/n!`.
.. function:: void mag_bernoulli_div_fac_ui(mag_t z, ulong n)
Sets *z* to an upper bound for `|B_n| / n!` where `B_n` denotes
a Bernoulli number.

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@ -19,7 +19,7 @@ a correct error bound for the numerical approximation of `p(n)`.
Optionally, hardware double arithmetic can be used for low-precision
terms. This gives a significant speedup for small (e.g. `n < 10^6`).
.. function:: void partitions_rademacher_bound(fmpr_t b, const fmpz_t n, ulong N)
.. function:: void partitions_rademacher_bound(arf_t b, const fmpz_t n, ulong N)
Sets `b` to an upper bound for
@ -33,7 +33,7 @@ terms. This gives a significant speedup for small (e.g. `n < 10^6`).
Hardy-Ramanujan-Rademacher formula when the series is taken up
to the term `t(n,N)` inclusive.
.. function:: partitions_hrr_sum_fmprb(fmprb_t x, const fmpz_t n, long N0, long N, int use_doubles)
.. function:: partitions_hrr_sum_arb(arb_t x, const fmpz_t n, long N0, long N, int use_doubles)
Evaluates the partial sum `\sum_{k=N_0}^N t(n,k)` of the
Hardy-Ramanujan-Rademacher series.
@ -57,7 +57,7 @@ terms. This gives a significant speedup for small (e.g. `n < 10^6`).
has been selected with :func:`flint_set_num_threads()`, the computation
time will be reduced by using two threads.
See :func:`partitions_hrr_sum_fmprb` for an explanation of the
See :func:`partitions_hrr_sum_arb` for an explanation of the
*use_doubles* option.
.. function:: void partitions_fmpz_ui(fmpz_t p, ulong n)
@ -71,5 +71,5 @@ terms. This gives a significant speedup for small (e.g. `n < 10^6`).
Computes the partition function `p(n)`, enabling the use of doubles
internally. This significantly speeds up evaluation for small `n`
(e.g. `n < 10^6`), but the error bounds are not certified
(see remarks for :func:`partitions_hrr_sum_fmprb`).
(see remarks for :func:`partitions_hrr_sum_arb`).

14
mag.h
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@ -288,7 +288,6 @@ mag_equal(const mag_t x, const mag_t y)
void mag_mul(mag_t z, const mag_t x, const mag_t y);
/* TODO: document */
void mag_mul_lower(mag_t z, const mag_t x, const mag_t y);
void mag_addmul(mag_t z, const mag_t x, const mag_t y);
@ -297,7 +296,6 @@ void mag_add_2exp_fmpz(mag_t z, const mag_t x, const fmpz_t e);
void mag_add(mag_t z, const mag_t x, const mag_t y);
/* TODO: document */
void mag_add_lower(mag_t z, const mag_t x, const mag_t y);
void mag_div(mag_t z, const mag_t x, const mag_t y);
@ -616,7 +614,6 @@ mag_cmp_2exp_si(const mag_t x, long e)
return (fmpz_cmp_si(MAG_EXPREF(x), e) <= 0) ? -1 : 1;
}
/* TODO: document */
static __inline__ mag_ptr
_mag_vec_init(long n)
{
@ -638,7 +635,6 @@ _mag_vec_clear(mag_ptr v, long n)
flint_free(v);
}
/* TODO: document/test */
static __inline__ void mag_set_d(mag_t z, double x)
{
fmpz_t e;
@ -651,23 +647,23 @@ static __inline__ void mag_set_d(mag_t z, double x)
double mag_d_log_upper_bound(double x);
double mag_d_log_lower_bound(double x);
/* TODO: document */
void mag_log1p(mag_t z, const mag_t x);
/* TODO: document/test */
/* TODO: test */
void mag_pow_ui(mag_t z, const mag_t x, ulong e);
void mag_pow_ui_lower(mag_t z, const mag_t x, ulong e);
/* TODO: document/test */
/* TODO: test */
void mag_fac_ui(mag_t z, ulong n);
void mag_rfac_ui(mag_t z, ulong n);
/* TODO: document/test */
/* TODO: test */
void mag_bernoulli_div_fac_ui(mag_t z, ulong n);
/* TODO: document/test */
/* TODO: test */
void mag_set_fmpz_2exp_fmpz_lower(mag_t z, const fmpz_t man, const fmpz_t exp);
/* TODO: test functions below */
static __inline__ void
mag_set_ui(mag_t z, ulong x)
{

116
mag/test/t-set_d.c Normal file
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@ -0,0 +1,116 @@
/*=============================================================================
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) 2014 Fredrik Johansson
******************************************************************************/
#include "double_extras.h"
#include "mag.h"
/* XXX: d_randtest is not good enough */
#define EXP_MINUS_32 2.3283064365386962891e-10
#define EXP_MINUS_64 5.42101086242752217e-20
double
d_randtest2(flint_rand_t state)
{
mp_limb_t m1, m2;
double t;
if (FLINT_BITS == 64)
{
m1 = n_randtest(state) | (UWORD(1) << (FLINT_BITS - 1));
t = ((double) m1) * EXP_MINUS_64;
}
else
{
m1 = n_randtest(state) | (UWORD(1) << (FLINT_BITS - 1));
m2 = n_randtest(state);
t = ((double) m1) * EXP_MINUS_32 +
((double) m2) * EXP_MINUS_64;
}
return t;
}
int main()
{
long iter;
flint_rand_t state;
printf("set_d....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 100000; iter++)
{
fmpr_t a, b, c;
mag_t m;
double x;
fmpr_init(a);
fmpr_init(b);
fmpr_init(c);
mag_init(m);
x = d_randtest2(state);
x = ldexp(x, 100 - n_randint(state, 200));
if (n_randint(state, 100) == 0)
x = 0.0;
fmpr_set_d(a, x);
mag_set_d(m, x);
mag_get_fmpr(b, m);
fmpr_set(c, a);
fmpr_mul_ui(c, c, 1025, MAG_BITS, FMPR_RND_UP);
fmpr_mul_2exp_si(c, c, -10);
MAG_CHECK_BITS(m)
if (!(fmpr_cmpabs(a, b) <= 0 && fmpr_cmpabs(b, c) <= 0))
{
printf("FAIL\n\n");
printf("a = "); fmpr_print(a); printf("\n\n");
printf("b = "); fmpr_print(b); printf("\n\n");
printf("c = "); fmpr_print(c); printf("\n\n");
abort();
}
fmpr_clear(a);
fmpr_clear(b);
fmpr_clear(c);
mag_clear(m);
}
flint_randclear(state);
flint_cleanup();
printf("PASS\n");
return EXIT_SUCCESS;
}