src/main/common/pwl.h

   1 /*
   2  * This file is part of Betaflight.
   3  *
   4  * Betaflight is free software. You can redistribute this software
   5  * and/or modify this software under the terms of the GNU General
   6  * Public License as published by the Free Software Foundation,
   7  * either version 3 of the License, or (at your option) any later
   8  * version.
   9  *
  10  * Betaflight is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  *
  14  * See the GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public
  17  * License along with this software.
  18  *
  19  * If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #pragma once
  23
  24 #include "utils.h"
  25
  26 #define PWL_DECLARE(name, size, xMinV, xMaxV)                           \
  27     STATIC_ASSERT((xMinV) < (xMaxV), "xMinV must be less than xMaxV");  \
  28     STATIC_ASSERT((size) > 1, "size must be more than 1");              \
  29     STATIC_ASSERT((size) < 33, "size must be less than 33");            \
  30     float name##_yValues[(size)];                                       \
  31     pwl_t name = {                                                      \
  32         .yValues = name##_yValues,                                      \
  33         .numPoints = (size),                                            \
  34         .xMin = (xMinV),                                                \
  35         .xMax = (xMaxV),                                                \
  36         .dx = ((xMaxV) - (xMinV)) / ((size) - 1)                        \
  37     }
  38
  39 typedef struct pwl_s {
  40     float *yValues;
  41     int numPoints;
  42     float xMin;
  43     float xMax;
  44     float dx;
  45 } pwl_t;
  46
  47 void pwlInitialize(pwl_t *pwl, float *yValues, int numPoints, float xMin, float xMax);
  48 void pwlFill(pwl_t *pwl, float (*function)(float, void*), void *arg);
  49 float pwlInterpolate(const pwl_t *pwl, float x);