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| Rev | Author | Line No. | Line |
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| 1702 | - | 1 | #include "AP_Math.h" |
| 2 | |||
| 3 | // a varient of asin() that checks the input ranges and ensures a |
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| 4 | // valid angle as output. If nan is given as input then zero is |
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| 5 | // returned. |
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| 6 | float safe_asin(float v) |
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| 7 | { |
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| 8 | if (isnan(v)) { |
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| 9 | return 0.0; |
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| 10 | } |
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| 11 | if (v >= 1.0) { |
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| 12 | return PI/2; |
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| 13 | } |
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| 14 | if (v <= -1.0) { |
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| 15 | return -PI/2; |
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| 16 | } |
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| 17 | return asin(v); |
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| 18 | } |
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| 19 | |||
| 20 | // a varient of sqrt() that checks the input ranges and ensures a |
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| 21 | // valid value as output. If a negative number is given then 0 is |
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| 22 | // returned. The reasoning is that a negative number for sqrt() in our |
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| 23 | // code is usually caused by small numerical rounding errors, so the |
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| 24 | // real input should have been zero |
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| 25 | float safe_sqrt(float v) |
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| 26 | { |
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| 27 | float ret = sqrt(v); |
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| 28 | if (isnan(ret)) { |
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| 29 | return 0; |
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| 30 | } |
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| 31 | return ret; |
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| 32 | } |
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| 33 | |||
| 34 | |||
| 35 | // find a rotation that is the combination of two other |
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| 36 | // rotations. This is used to allow us to add an overall board |
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| 37 | // rotation to an existing rotation of a sensor such as the compass |
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| 38 | // Note that this relies the set of rotations being complete. The |
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| 39 | // optional 'found' parameter is for the test suite to ensure that it is. |
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| 40 | enum Rotation rotation_combination(enum Rotation r1, enum Rotation r2, bool *found) |
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| 41 | { |
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| 42 | Vector3f tv1, tv2; |
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| 43 | enum Rotation r; |
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| 44 | tv1(1,2,3); |
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| 45 | tv1.rotate(r1); |
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| 46 | tv1.rotate(r2); |
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| 47 | |||
| 48 | for (r=ROTATION_NONE; r<ROTATION_MAX; |
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| 49 | r = (enum Rotation)((uint8_t)r+1)) { |
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| 50 | Vector3f diff; |
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| 51 | tv2(1,2,3); |
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| 52 | tv2.rotate(r); |
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| 53 | diff = tv1 - tv2; |
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| 54 | if (diff.length() < 1.0e-6) { |
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| 55 | // we found a match |
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| 56 | if (found) { |
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| 57 | *found = true; |
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| 58 | } |
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| 59 | return r; |
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| 60 | } |
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| 61 | } |
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| 62 | |||
| 63 | // we found no matching rotation. Someone has edited the |
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| 64 | // rotations list and broken its completeness property ... |
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| 65 | if (found) { |
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| 66 | *found = false; |
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| 67 | } |
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| 68 | return ROTATION_NONE; |
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| 69 | } |