C语言-查表法计算正余弦函数

#include "math_utility.h" #include "math.h" short sin_xita[512] = { 0,31,61,92,123,153,184,215,245,276,307, 337,368,399,429,460,491,521,552,583,613, 644,674,705,736,766,797,827,858,889,919, 950,980,1011,1041,1072,1102,1133,1163,1194,1224, 1255,1285,1315,1346,1376,1407,1437,1467,1498,1528, 1558,1589,1619,1649,1679,1710,1740,1770,1800,1830, 1861,1891,1921,1951,1981,2011,2041,2071,2101,2131, 2161,2191,2221,2251,2281,2311,2340,2370,2400,2430, 2460,2489,2519,2549,2578,2608,2638,2667,2697,2726, 2756,2785,2815,2844,2873,2903,2932,2962,2991,3020, 3049,3078,3108,3137,3166,3195,3224,3253,3282,3311, 3340,3369,3398,3427,3455,3484,3513,3542,3570,3599, 3628,3656,3685,3713,3742,3770,3798,3827,3855,3883, 3912,3940,3968,3996,4024,4052,4080,4108,4136,4164, 4192,4220,4248,4276,4303,4331,4359,4386,4414,4441, 4469,4496,4523,4551,4578,4605,4633,4660,4687,4714, 4741,4768,4795,4822,4849,4875,4902,4929,4956,4982, 5009,5035,5062,5088,5115,5141,5167,5194,5220,5246, 5272,5298,5324,5350,5376,5402,5428,5453,5479,5505, 5530,5556,5581,5607,5632,5657,5683,5708,5733,5758, 5783,5808,5833,5858,5883,5908,5932,5957,5982,6006, 6031,6055,6079,6104,6128,6152,6176,6201,6225,6249, 6273,6296,6320,6344,6368,6391,6415,6438,6462,6485, 6508,6532,6555,6578,6601,6624,6647,6670,6693,6716, 6738,6761,6783,6806,6828,6851,6873,6895,6918,6940, 6962,6984,7006,7028,7049,7071,7093,7114,7136,7157, 7179,7200,7221,7242,7264,7285,7306,7327,7347,7368, 7389,7410,7430,7451,7471,7491,7512,7532,7552,7572, 7592,7612,7632,7652,7671,7691,7711,7730,7750,7769, 7788,7807,7827,7846,7865,7883,7902,7921,7940,7958, 7977,7995,8014,8032,8050,8068,8087,8105,8123,8140, 8158,8176,8193,8211,8228,8246,8263,8280,8298,8315, 8332,8349,8365,8382,8399,8416,8432,8449,8465,8481, 8497,8514,8530,8546,8561,8577,8593,8609,8624,8640, 8655,8670,8686,8701,8716,8731,8746,8761,8775,8790, 8805,8819,8834,8848,8862,8876,8890,8904,8918,8932, 8946,8960,8973,8987,9000,9013,9027,9040,9053,9066, 9079,9092,9104,9117,9130,9142,9154,9167,9179,9191, 9203,9215,9227,9239,9250,9262,9274,9285,9296,9308, 9319,9330,9341,9352,9363,9373,9384,9395,9405,9415, 9426,9436,9446,9456,9466,9476,9486,9495,9505,9514, 9524,9533,9542,9551,9560,9569,9578,9587,9596,9604, 9613,9621,9630,9638,9646,9654,9662,9670,9678,9685, 9693,9700,9708,9715,9722,9729,9736,9743,9750,9757, 9764,9770,9777,9783,9789,9796,9802,9808,9814,9820, 9825,9831,9837,9842,9847,9853,9858,9863,9868,9873, 9878,9883,9887,9892,9896,9901,9905,9909,9913,9917, 9921,9925,9929,9932,9936,9939,9942,9946,9949,9952, 9955,9958,9960,9963,9966,9968,9971,9973,9975,9977, 9979,9981,9983,9985,9986,9988,9989,9991,9992,9993, 9994,9995,9996,9997,9998,9998,9999,9999,10000,10000,10000 }; //将弧度限制在2PI范围 float rad_limit(float rad) { float res = fmod(rad,_2PI); return res >= 0? res:(res+_2PI); } //注意 角度必须控制在0~2PI float sint(float rad) { float res=0; int rod=_round(325.949323f * rad); if ( rad < _PI_2 ) { if(rod > 511) rod = 511; res= 0.0001f * sin_xita[rod]; } else if ( rad < _PI ) { if(rod > 1023) rod = 1023; res= 0.0001f * sin_xita[1023 - rod]; } else if ( rad < _3PI_2 ) { if(rod > 1534) rod = 1534; res= -0.0001f * sin_xita[-1023 + rod]; } else { if(rod > 2047) rod = 2047; res= -0.0001f * sin_xita[2047 - rod]; } return res; } //注意 角度必须控制在0~2PI float cost(float rad) { float a_sin = rad + _PI_2; a_sin = a_sin > _2PI ? a_sin - _2PI : a_sin; return sint ( a_sin ); } float _sqrtApprox(float number) {//low in fat long i; float y; // float x; // const float f = 1.5F; // better precision // x = number * 0.5F; y = number; i = * ( long * ) &y; i = 0x5f375a86 - ( i >> 1 ); y = * ( float * ) &i; // y = y * ( f - ( x * y * y ) ); // better precision return number * y; }