src/main/common/maths.h

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #pragma once
  22
  23 #include <stdint.h>
  24
  25 #ifndef sq
  26 #define sq(x) ((x)*(x))
  27 #endif
  28 #define power3(x) ((x)*(x)*(x))
  29
  30 // Undefine this for use libc sinf/cosf. Keep this defined to use fast sin/cos approximations
  31 #define FAST_MATH             // order 9 approximation
  32 #define VERY_FAST_MATH        // order 7 approximation
  33
  34 // Use floating point M_PI instead explicitly.
  35 #define M_PIf       3.14159265358979323846f
  36 #define M_EULERf    2.71828182845904523536f
  37
  38 #define RAD    (M_PIf / 180.0f)
  39 #define DEGREES_TO_DECIDEGREES(angle) ((angle) * 10)
  40 #define DECIDEGREES_TO_DEGREES(angle) ((angle) / 10)
  41 #define DECIDEGREES_TO_RADIANS(angle) ((angle) / 10.0f * 0.0174532925f)
  42 #define DEGREES_TO_RADIANS(angle) ((angle) * 0.0174532925f)
  43
  44 #define CM_S_TO_KM_H(centimetersPerSecond) ((centimetersPerSecond) * 36 / 1000)
  45 #define CM_S_TO_MPH(centimetersPerSecond) ((centimetersPerSecond) * 10000 / 5080 / 88)
  46
  47 #define MIN(a,b) \
  48   __extension__ ({ __typeof__ (a) _a = (a); \
  49   __typeof__ (b) _b = (b); \
  50   _a < _b ? _a : _b; })
  51 #define MAX(a,b) \
  52   __extension__ ({ __typeof__ (a) _a = (a); \
  53   __typeof__ (b) _b = (b); \
  54   _a > _b ? _a : _b; })
  55 #define ABS(x) \
  56   __extension__ ({ __typeof__ (x) _x = (x); \
  57   _x > 0 ? _x : -_x; })
  58
  59 #define Q12 (1 << 12)
  60
  61 #define HZ_TO_INTERVAL(x) (1.0f / (x))
  62 #define HZ_TO_INTERVAL_US(x) (1000000 / (x))
  63
  64 typedef int32_t fix12_t;
  65
  66 typedef struct stdev_s
  67 {
  68     float m_oldM, m_newM, m_oldS, m_newS;
  69     int m_n;
  70 } stdev_t;
  71
  72 // Floating point 3 vector.
  73 typedef struct fp_vector {
  74     float X;
  75     float Y;
  76     float Z;
  77 } t_fp_vector_def;
  78
  79 typedef union u_fp_vector {
  80     float A[3];
  81     t_fp_vector_def V;
  82 } t_fp_vector;
  83
  84 // Floating point Euler angles.
  85 // Be carefull, could be either of degrees or radians.
  86 typedef struct fp_angles {
  87     float roll;
  88     float pitch;
  89     float yaw;
  90 } fp_angles_def;
  91
  92 typedef union {
  93     float raw[3];
  94     fp_angles_def angles;
  95 } fp_angles_t;
  96
  97 typedef struct fp_rotationMatrix_s {
  98     float m[3][3];              // matrix
  99 } fp_rotationMatrix_t;
 100
 101 int gcd(int num, int denom);
 102 int32_t applyDeadband(int32_t value, int32_t deadband);
 103 float fapplyDeadband(float value, float deadband);
 104
 105 void devClear(stdev_t *dev);
 106 void devPush(stdev_t *dev, float x);
 107 float devVariance(stdev_t *dev);
 108 float devStandardDeviation(stdev_t *dev);
 109 float degreesToRadians(int16_t degrees);
 110
 111 int scaleRange(int x, int srcFrom, int srcTo, int destFrom, int destTo);
 112 float scaleRangef(float x, float srcFrom, float srcTo, float destFrom, float destTo);
 113
 114 void buildRotationMatrix(fp_angles_t *delta, fp_rotationMatrix_t *rotation);
 115 void applyMatrixRotation(float *v, fp_rotationMatrix_t *rotationMatrix);
 116
 117 int32_t quickMedianFilter3(int32_t * v);
 118 int32_t quickMedianFilter5(int32_t * v);
 119 int32_t quickMedianFilter7(int32_t * v);
 120 int32_t quickMedianFilter9(int32_t * v);
 121
 122 float quickMedianFilter3f(float * v);
 123 float quickMedianFilter5f(float * v);
 124 float quickMedianFilter7f(float * v);
 125 float quickMedianFilter9f(float * v);
 126
 127 #if defined(FAST_MATH) || defined(VERY_FAST_MATH)
 128 float sin_approx(float x);
 129 float cos_approx(float x);
 130 float atan2_approx(float y, float x);
 131 float acos_approx(float x);
 132 #define tan_approx(x)       (sin_approx(x) / cos_approx(x))
 133 float exp_approx(float val);
 134 float log_approx(float val);
 135 float pow_approx(float a, float b);
 136 #else
 137 #define sin_approx(x)       sinf(x)
 138 #define cos_approx(x)       cosf(x)
 139 #define atan2_approx(y,x)   atan2f(y,x)
 140 #define acos_approx(x)      acosf(x)
 141 #define tan_approx(x)       tanf(x)
 142 #define exp_approx(x)       expf(x)
 143 #define log_approx(x)       logf(x)
 144 #define pow_approx(a, b)    powf(b, a)
 145 #endif
 146
 147 void arraySubInt32(int32_t *dest, int32_t *array1, int32_t *array2, int count);
 148
 149 int16_t qPercent(fix12_t q);
 150 int16_t qMultiply(fix12_t q, int16_t input);
 151 fix12_t qConstruct(int16_t num, int16_t den);
 152
 153 static inline int constrain(int amt, int low, int high)
 154 {
 155     if (amt < low)
 156         return low;
 157     else if (amt > high)
 158         return high;
 159     else
 160         return amt;
 161 }
 162
 163 static inline float constrainf(float amt, float low, float high)
 164 {
 165     if (amt < low)
 166         return low;
 167     else if (amt > high)
 168         return high;
 169     else
 170         return amt;
 171 }