From aecb8f2dcca8420384ffd76d06de443cf82b6187 Mon Sep 17 00:00:00 2001 From: Bruno Haible Date: Sun, 11 Mar 2012 14:43:42 +0100 Subject: [PATCH] Tests for module 'log2'. * modules/log2-tests: New file. * tests/test-log2.c: New file. * tests/test-log2.h: New file. --- ChangeLog | 5 ++ modules/log2-tests | 17 ++++++ tests/test-log2.c | 53 ++++++++++++++++++ tests/test-log2.h | 131 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 206 insertions(+) create mode 100644 modules/log2-tests create mode 100644 tests/test-log2.c create mode 100644 tests/test-log2.h diff --git a/ChangeLog b/ChangeLog index dc323d7ac6..196cdeef8f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,10 @@ 2012-03-11 Bruno Haible + Tests for module 'log2'. + * modules/log2-tests: New file. + * tests/test-log2.c: New file. + * tests/test-log2.h: New file. + New module 'log2'. * lib/math.in.h (log2): New declaration. * lib/log2.c: New file. diff --git a/modules/log2-tests b/modules/log2-tests new file mode 100644 index 0000000000..2fc41fc6eb --- /dev/null +++ b/modules/log2-tests @@ -0,0 +1,17 @@ +Files: +tests/test-log2.c +tests/test-log2.h +tests/minus-zero.h +tests/signature.h +tests/macros.h +tests/randomd.c + +Depends-on: + +configure.ac: + +Makefile.am: +TESTS += test-log2 +check_PROGRAMS += test-log2 +test_log2_SOURCES = test-log2.c randomd.c +test_log2_LDADD = $(LDADD) @LOG2_LIBM@ diff --git a/tests/test-log2.c b/tests/test-log2.c new file mode 100644 index 0000000000..8c8ae8bdf0 --- /dev/null +++ b/tests/test-log2.c @@ -0,0 +1,53 @@ +/* Test of log2() function. + Copyright (C) 2010-2012 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +/* Written by Bruno Haible , 2012. */ + +#include + +#include + +#include "signature.h" +SIGNATURE_CHECK (log2, double, (double)); + +#include + +#include "minus-zero.h" +#include "macros.h" + +#define DOUBLE double +#define HUGEVAL HUGE_VAL +#define L_(literal) literal +#define MANT_DIG DBL_MANT_DIG +#define MAX_EXP DBL_MAX_EXP +#define MIN_EXP DBL_MIN_EXP +#define MINUS_ZERO minus_zerod +#define LOG2 log2 +#define RANDOM randomd +#include "test-log2.h" + +int +main () +{ + /* A particular value. */ + x = 0.6; + y = log2 (x); + ASSERT (y >= -0.7369655942 && y <= -0.7369655941); + + test_function (); + + return 0; +} diff --git a/tests/test-log2.h b/tests/test-log2.h new file mode 100644 index 0000000000..5872a790d7 --- /dev/null +++ b/tests/test-log2.h @@ -0,0 +1,131 @@ +/* Test of log2*() function family. + Copyright (C) 2012 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +static void +test_function (void) +{ + int i; + int j; + const DOUBLE TWO_MANT_DIG = + /* Assume MANT_DIG <= 5 * 31. + Use the identity + n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */ + (DOUBLE) (1U << ((MANT_DIG - 1) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5)); + + /* Pole. */ + ASSERT (LOG2 (L_(0.0)) == - HUGEVAL); + ASSERT (LOG2 (MINUS_ZERO) == - HUGEVAL); + + /* Integral values. */ + { + DOUBLE x = L_(1.0); + DOUBLE y = LOG2 (x); + ASSERT (y == L_(0.0)); + } + { + int e; + DOUBLE x; + DOUBLE y; + for (e = 0, x = L_(0.0), y = L_(1.0); + e <= MAX_EXP - 1; + e++, x = x + L_(1.0), y = y * L_(2.0)) + { + /* Invariant: x = e, y = 2^e. */ + DOUBLE z = LOG2 (y); + ASSERT (z == x); + } + } + { + int e; + DOUBLE x; + DOUBLE y; + for (e = 0, x = L_(0.0), y = L_(1.0); + e >= MIN_EXP - 1; + e--, x = x - L_(1.0), y = y * L_(0.5)) + { + /* Invariant: x = e, y = 2^e. */ + DOUBLE z = LOG2 (y); + ASSERT (z == x); + } + } + + /* Randomized tests. */ + { + /* Error bound, in ulps. */ + const DOUBLE err_bound = + (sizeof (DOUBLE) > sizeof (double) ? +#if defined __i386__ && defined __FreeBSD__ + /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of + precision in the compiler but 64 bits of precision at runtime. See + . + The compiler has truncated all 'long double' literals in log2l.c to + 53 bits of precision. */ + L_(8193.0) +#else + L_(5.0) +#endif + : L_(5.0)); + + for (i = 0; i < SIZEOF (RANDOM); i++) + { + DOUBLE x = L_(16.0) * RANDOM[i] + L_(1.0); /* 1.0 <= x <= 17.0 */ + DOUBLE y = LOG2 (x); + DOUBLE z = LOG2 (L_(1.0) / x); + DOUBLE err = y + z; + ASSERT (y >= L_(0.0)); + ASSERT (z <= L_(0.0)); + ASSERT (err > - err_bound / TWO_MANT_DIG + && err < err_bound / TWO_MANT_DIG); + } + } + + { + /* Error bound, in ulps. */ + const DOUBLE err_bound = + (sizeof (DOUBLE) > sizeof (double) ? +#if defined __i386__ && defined __FreeBSD__ + /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of + precision in the compiler but 64 bits of precision at runtime. See + . + The compiler has truncated all 'long double' literals in log2l.c to + 53 bits of precision. */ + L_(8193.0) +#else + L_(9.0) +#endif + : L_(9.0)); + + for (i = 0; i < SIZEOF (RANDOM) / 5; i++) + for (j = 0; j < SIZEOF (RANDOM) / 5; j++) + { + DOUBLE x = L_(17.0) / (L_(16.0) - L_(15.0) * RANDOM[i]) - L_(1.0); + DOUBLE y = L_(17.0) / (L_(16.0) - L_(15.0) * RANDOM[j]) - L_(1.0); + /* 1/16 <= x,y <= 16 */ + DOUBLE z = L_(1.0) / (x * y); + /* Approximately x * y * z = 1. */ + DOUBLE err = LOG2 (x) + LOG2 (y) + LOG2 (z); + ASSERT (err > - err_bound / TWO_MANT_DIG + && err < err_bound / TWO_MANT_DIG); + } + } +} + +volatile DOUBLE x; +DOUBLE y; -- 2.39.5