mirror of https://github.com/ArduPilot/ardupilot
129 lines
3.0 KiB
C++
129 lines
3.0 KiB
C++
#include "AP_Math.h"
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#include <float.h>
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// a varient of asin() that checks the input ranges and ensures a
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// valid angle as output. If nan is given as input then zero is
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// returned.
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float safe_asin(float v)
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{
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if (isnan(v)) {
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return 0.0f;
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}
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if (v >= 1.0f) {
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return PI/2;
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}
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if (v <= -1.0f) {
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return -PI/2;
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}
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return asinf(v);
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}
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// a varient of sqrt() that checks the input ranges and ensures a
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// valid value as output. If a negative number is given then 0 is
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// returned. The reasoning is that a negative number for sqrt() in our
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// code is usually caused by small numerical rounding errors, so the
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// real input should have been zero
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float safe_sqrt(float v)
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{
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float ret = sqrtf(v);
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if (isnan(ret)) {
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return 0;
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}
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return ret;
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}
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#if ROTATION_COMBINATION_SUPPORT
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// find a rotation that is the combination of two other
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// rotations. This is used to allow us to add an overall board
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// rotation to an existing rotation of a sensor such as the compass
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// Note that this relies the set of rotations being complete. The
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// optional 'found' parameter is for the test suite to ensure that it is.
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enum Rotation rotation_combination(enum Rotation r1, enum Rotation r2, bool *found)
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{
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Vector3f tv1, tv2;
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enum Rotation r;
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tv1(1,2,3);
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tv1.rotate(r1);
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tv1.rotate(r2);
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for (r=ROTATION_NONE; r<ROTATION_MAX;
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r = (enum Rotation)((uint8_t)r+1)) {
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Vector3f diff;
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tv2(1,2,3);
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tv2.rotate(r);
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diff = tv1 - tv2;
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if (diff.length() < 1.0e-6f) {
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// we found a match
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if (found) {
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*found = true;
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}
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return r;
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}
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}
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// we found no matching rotation. Someone has edited the
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// rotations list and broken its completeness property ...
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if (found) {
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*found = false;
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}
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return ROTATION_NONE;
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}
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#endif
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// constrain a value
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float constrain_float(float amt, float low, float high)
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{
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// the check for NaN as a float prevents propogation of
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// floating point errors through any function that uses
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// constrain_float(). The normal float semantics already handle -Inf
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// and +Inf
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if (isnan(amt)) {
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return (low+high)*0.5f;
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}
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return ((amt)<(low)?(low):((amt)>(high)?(high):(amt)));
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}
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// constrain a int16_t value
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int16_t constrain_int16(int16_t amt, int16_t low, int16_t high) {
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return ((amt)<(low)?(low):((amt)>(high)?(high):(amt)));
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}
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// constrain a int32_t value
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int32_t constrain_int32(int32_t amt, int32_t low, int32_t high) {
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return ((amt)<(low)?(low):((amt)>(high)?(high):(amt)));
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}
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// degrees -> radians
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float radians(float deg) {
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return deg * DEG_TO_RAD;
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}
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// radians -> degrees
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float degrees(float rad) {
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return rad * RAD_TO_DEG;
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}
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// square
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float sq(float v) {
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return v*v;
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}
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// 2D vector length
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float pythagorous2(float a, float b) {
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return sqrtf(sq(a)+sq(b));
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}
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// 3D vector length
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float pythagorous3(float a, float b, float c) {
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return sqrtf(sq(a)+sq(b)+sq(c));
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}
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float maxf(float a, float b)
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{
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return (a>b?a:b);
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}
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float minf(float a, float b)
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{
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return (a<b?a:b);
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}
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