diff options
Diffstat (limited to 'src/dpdk_lib18/librte_sched/rte_approx.c')
| -rwxr-xr-x | src/dpdk_lib18/librte_sched/rte_approx.c | 196 |
1 files changed, 0 insertions, 196 deletions
diff --git a/src/dpdk_lib18/librte_sched/rte_approx.c b/src/dpdk_lib18/librte_sched/rte_approx.c deleted file mode 100755 index 771c9518..00000000 --- a/src/dpdk_lib18/librte_sched/rte_approx.c +++ /dev/null @@ -1,196 +0,0 @@ -/*- - * BSD LICENSE - * - * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * * Neither the name of Intel Corporation nor the names of its - * contributors may be used to endorse or promote products derived - * from this software without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -#include <stdlib.h> - -#include "rte_approx.h" - -/* - * Based on paper "Approximating Rational Numbers by Fractions" by Michal - * Forisek forisek@dcs.fmph.uniba.sk - * - * Given a rational number alpha with 0 < alpha < 1 and a precision d, the goal - * is to find positive integers p, q such that alpha - d < p/q < alpha + d, and - * q is minimal. - * - * http://people.ksp.sk/~misof/publications/2007approx.pdf - */ - -/* fraction comparison: compare (a/b) and (c/d) */ -static inline uint32_t -less(uint32_t a, uint32_t b, uint32_t c, uint32_t d) -{ - return (a*d < b*c); -} - -static inline uint32_t -less_or_equal(uint32_t a, uint32_t b, uint32_t c, uint32_t d) -{ - return (a*d <= b*c); -} - -/* check whether a/b is a valid approximation */ -static inline uint32_t -matches(uint32_t a, uint32_t b, - uint32_t alpha_num, uint32_t d_num, uint32_t denum) -{ - if (less_or_equal(a, b, alpha_num - d_num, denum)) - return 0; - - if (less(a ,b, alpha_num + d_num, denum)) - return 1; - - return 0; -} - -static inline void -find_exact_solution_left(uint32_t p_a, uint32_t q_a, uint32_t p_b, uint32_t q_b, - uint32_t alpha_num, uint32_t d_num, uint32_t denum, uint32_t *p, uint32_t *q) -{ - uint32_t k_num = denum * p_b - (alpha_num + d_num) * q_b; - uint32_t k_denum = (alpha_num + d_num) * q_a - denum * p_a; - uint32_t k = (k_num / k_denum) + 1; - - *p = p_b + k * p_a; - *q = q_b + k * q_a; -} - -static inline void -find_exact_solution_right(uint32_t p_a, uint32_t q_a, uint32_t p_b, uint32_t q_b, - uint32_t alpha_num, uint32_t d_num, uint32_t denum, uint32_t *p, uint32_t *q) -{ - uint32_t k_num = - denum * p_b + (alpha_num - d_num) * q_b; - uint32_t k_denum = - (alpha_num - d_num) * q_a + denum * p_a; - uint32_t k = (k_num / k_denum) + 1; - - *p = p_b + k * p_a; - *q = q_b + k * q_a; -} - -static int -find_best_rational_approximation(uint32_t alpha_num, uint32_t d_num, uint32_t denum, uint32_t *p, uint32_t *q) -{ - uint32_t p_a, q_a, p_b, q_b; - - /* check assumptions on the inputs */ - if (!((0 < d_num) && (d_num < alpha_num) && (alpha_num < denum) && (d_num + alpha_num < denum))) { - return -1; - } - - /* set initial bounds for the search */ - p_a = 0; - q_a = 1; - p_b = 1; - q_b = 1; - - while (1) { - uint32_t new_p_a, new_q_a, new_p_b, new_q_b; - uint32_t x_num, x_denum, x; - int aa, bb; - - /* compute the number of steps to the left */ - x_num = denum * p_b - alpha_num * q_b; - x_denum = - denum * p_a + alpha_num * q_a; - x = (x_num + x_denum - 1) / x_denum; /* x = ceil(x_num / x_denum) */ - - /* check whether we have a valid approximation */ - aa = matches(p_b + x * p_a, q_b + x * q_a, alpha_num, d_num, denum); - bb = matches(p_b + (x-1) * p_a, q_b + (x - 1) * q_a, alpha_num, d_num, denum); - if (aa || bb) { - find_exact_solution_left(p_a, q_a, p_b, q_b, alpha_num, d_num, denum, p, q); - return 0; - } - - /* update the interval */ - new_p_a = p_b + (x - 1) * p_a ; - new_q_a = q_b + (x - 1) * q_a; - new_p_b = p_b + x * p_a ; - new_q_b = q_b + x * q_a; - - p_a = new_p_a ; - q_a = new_q_a; - p_b = new_p_b ; - q_b = new_q_b; - - /* compute the number of steps to the right */ - x_num = alpha_num * q_b - denum * p_b; - x_denum = - alpha_num * q_a + denum * p_a; - x = (x_num + x_denum - 1) / x_denum; /* x = ceil(x_num / x_denum) */ - - /* check whether we have a valid approximation */ - aa = matches(p_b + x * p_a, q_b + x * q_a, alpha_num, d_num, denum); - bb = matches(p_b + (x - 1) * p_a, q_b + (x - 1) * q_a, alpha_num, d_num, denum); - if (aa || bb) { - find_exact_solution_right(p_a, q_a, p_b, q_b, alpha_num, d_num, denum, p, q); - return 0; - } - - /* update the interval */ - new_p_a = p_b + (x - 1) * p_a; - new_q_a = q_b + (x - 1) * q_a; - new_p_b = p_b + x * p_a; - new_q_b = q_b + x * q_a; - - p_a = new_p_a; - q_a = new_q_a; - p_b = new_p_b; - q_b = new_q_b; - } -} - -int rte_approx(double alpha, double d, uint32_t *p, uint32_t *q) -{ - uint32_t alpha_num, d_num, denum; - - /* Check input arguments */ - if (!((0.0 < d) && (d < alpha) && (alpha < 1.0))) { - return -1; - } - - if ((p == NULL) || (q == NULL)) { - return -2; - } - - /* Compute alpha_num, d_num and denum */ - denum = 1; - while (d < 1) { - alpha *= 10; - d *= 10; - denum *= 10; - } - alpha_num = (uint32_t) alpha; - d_num = (uint32_t) d; - - /* Perform approximation */ - return find_best_rational_approximation(alpha_num, d_num, denum, p, q); -} |