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| 2189 | - | 1 | #include "AP_Math.h" |
| 2 | #include <math.h> |
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| 3 | |||
| 4 | // a varient of asin() that checks the input ranges and ensures a |
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| 5 | // valid angle as output. If nan is given as input then zero is |
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| 6 | // returned. |
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| 7 | float safe_asin(float v) |
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| 8 | { |
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| 9 | if (isnan(v)) { |
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| 10 | return 0.0; |
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| 11 | } |
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| 12 | if (v >= 1.0) { |
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| 13 | return M_PI/2; |
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| 14 | } |
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| 15 | if (v <= -1.0) { |
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| 16 | return -M_PI/2; |
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| 17 | } |
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| 18 | return asin(v); |
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| 19 | } |
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| 20 | |||
| 21 | // a varient of sqrt() that checks the input ranges and ensures a |
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| 22 | // valid value as output. If a negative number is given then 0 is |
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| 23 | // returned. The reasoning is that a negative number for sqrt() in our |
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| 24 | // code is usually caused by small numerical rounding errors, so the |
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| 25 | // real input should have been zero |
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| 26 | float safe_sqrt(float v) |
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| 27 | { |
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| 28 | float ret = sqrt(v); |
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| 29 | if (isnan(ret)) { |
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| 30 | return 0; |
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| 31 | } |
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| 32 | return ret; |
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| 33 | } |
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| 34 | |||
| 35 | |||
| 36 | // find a rotation that is the combination of two other |
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| 37 | // rotations. This is used to allow us to add an overall board |
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| 38 | // rotation to an existing rotation of a sensor such as the compass |
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| 39 | // Note that this relies the set of rotations being complete. The |
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| 40 | // optional 'found' parameter is for the test suite to ensure that it is. |
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| 41 | enum Rotation rotation_combination(enum Rotation r1, enum Rotation r2, bool *found) |
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| 42 | { |
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| 43 | Vector3f tv1, tv2; |
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| 44 | enum Rotation r; |
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| 45 | tv1(1,2,3); |
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| 46 | tv1.rotate(r1); |
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| 47 | tv1.rotate(r2); |
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| 48 | |||
| 49 | for (r=ROTATION_NONE; r<ROTATION_MAX; |
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| 50 | r = (enum Rotation)((uint8_t)r+1)) { |
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| 51 | Vector3f diff; |
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| 52 | tv2(1,2,3); |
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| 53 | tv2.rotate(r); |
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| 54 | diff = tv1 - tv2; |
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| 55 | if (diff.length() < 1.0e-6) { |
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| 56 | // we found a match |
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| 57 | if (found) { |
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| 58 | *found = true; |
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| 59 | } |
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| 60 | return r; |
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| 61 | } |
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| 62 | } |
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| 63 | |||
| 64 | // we found no matching rotation. Someone has edited the |
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| 65 | // rotations list and broken its completeness property ... |
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| 66 | if (found) { |
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| 67 | *found = false; |
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| 68 | } |
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| 69 | return ROTATION_NONE; |
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| 70 | } |