三角函数快速算法

三角函数快速算法(反正切，正余弦，开平方)

2010-09-08 09:14:27| 分类：| 标签：|字号订阅

#define REAL float

#define TAN_MAP_RES 0.003921569 /* (smallest non-zero value in table) */

#define RAD_PER_DEG 0.017453293

#define TAN_MAP_SIZE 256

#define MY_PPPIII 3.14159

#define MY_PPPIII_HALF 1.570796

float fast_atan_table[257] = {

0.000000e+00, 3.921549e-03, 7.842976e-03, 1.176416e-02,

1.568499e-02, 1.960533e-02,

2.352507e-02, 2.744409e-02,

3.136226e-02, 3.527947e-02, 3.919560e-02,

4.311053e-02,

4.702413e-02,

5.093629e-02, 5.484690e-02, 5.875582e-02,

6.266295e-02, 6.656816e-02,

7.047134e-02, 7.437238e-02,

7.827114e-02, 8.216752e-02, 8.606141e-02, 8.995267e-02,

9.384121e-02, 9.772691e-02, 1.016096e-01, 1.054893e-01,

1.093658e-01, 1.132390e-01, 1.171087e-01, 1.209750e-01,

1.248376e-01, 1.286965e-01, 1.325515e-01, 1.364026e-01,

1.402496e-01, 1.440924e-01, 1.479310e-01, 1.517652e-01,

1.555948e-01, 1.594199e-01, 1.632403e-01, 1.670559e-01,

1.708665e-01, 1.746722e-01, 1.784728e-01, 1.822681e-01,

1.860582e-01, 1.898428e-01, 1.936220e-01, 1.973956e-01,

2.011634e-01, 2.049255e-01, 2.086818e-01, 2.124320e-01,

2.161762e-01, 2.199143e-01, 2.236461e-01, 2.273716e-01,

2.310907e-01, 2.348033e-01, 2.385093e-01, 2.422086e-01,

2.459012e-01, 2.495869e-01, 2.532658e-01, 2.569376e-01,

2.606024e-01, 2.642600e-01, 2.679104e-01, 2.715535e-01,

2.751892e-01, 2.788175e-01, 2.824383e-01, 2.860514e-01,

2.896569e-01, 2.932547e-01, 2.968447e-01,

3.004268e-01,

3.040009e-01, 3.075671e-01, 3.111252e-01, 3.146752e-01,

3.182170e-01, 3.217506e-01, 3.252758e-01, 3.287927e-01,

3.323012e-01, 3.358012e-01, 3.392926e-01, 3.427755e-01,

3.462497e-01, 3.497153e-01, 3.531721e-01, 3.566201e-01,

3.600593e-01, 3.634896e-01, 3.669110e-01, 3.703234e-01,

3.737268e-01, 3.771211e-01, 3.805064e-01, 3.838825e-01,

3.872494e-01, 3.906070e-01, 3.939555e-01, 3.972946e-01,

4.006244e-01, 4.039448e-01, 4.072558e-01, 4.105574e-01,

4.138496e-01, 4.171322e-01, 4.204054e-01, 4.236689e-01,

4.269229e-01, 4.301673e-01, 4.334021e-01, 4.366272e-01,

4.398426e-01, 4.430483e-01, 4.462443e-01, 4.494306e-01,

4.526070e-01, 4.557738e-01, 4.589307e-01, 4.620778e-01,

4.652150e-01, 4.683424e-01, 4.714600e-01, 4.745676e-01,4.776654e-01, 4.807532e-01, 4.838312e-01,

4.868992e-01,

4.899573e-01, 4.930055e-01, 4.960437e-01, 4.990719e-01,

5.020902e-01, 5.050985e-01, 5.080968e-01, 5.110852e-01, 5.140636e-01, 5.170320e-01, 5.199904e-01, 5.229388e-01, 5.258772e-01, 5.288056e-01, 5.317241e-01, 5.346325e-01, 5.375310e-01, 5.404195e-01, 5.432980e-01, 5.461666e-01, 5.490251e-01, 5.518738e-01, 5.547124e-01, 5.575411e-01, 5.603599e-01, 5.631687e-01, 5.659676e-01, 5.687566e-01, 5.715357e-01, 5.743048e-01, 5.770641e-01, 5.798135e-01, 5.825531e-01, 5.852828e-01, 5.880026e-01, 5.907126e-01,

5.934128e-01, 5.961032e-01, 5.987839e-01,

6.014547e-01,

6.041158e-01, 6.067672e-01, 6.094088e-01, 6.120407e-01, 6.146630e-01, 6.172755e-01, 6.198784e-01, 6.224717e-01, 6.250554e-01, 6.276294e-01, 6.301939e-01, 6.327488e-01, 6.352942e-01, 6.378301e-01, 6.403565e-01, 6.428734e-01, 6.453808e-01, 6.478788e-01, 6.503674e-01, 6.528466e-01, 6.553165e-01, 6.577770e-01, 6.602282e-01, 6.626701e-01, 6.651027e-01, 6.675261e-01, 6.699402e-01, 6.723452e-01, 6.747409e-01, 6.771276e-01, 6.795051e-01, 6.818735e-01, 6.842328e-01, 6.865831e-01, 6.889244e-01, 6.912567e-01,

6.935800e-01, 6.958943e-01, 6.981998e-01,

7.004964e-01,

7.027841e-01, 7.050630e-01, 7.073330e-01, 7.095943e-01, 7.118469e-01, 7.140907e-01, 7.163258e-01, 7.185523e-01, 7.207701e-01, 7.229794e-01, 7.251800e-01, 7.273721e-01, 7.295557e-01, 7.317307e-01, 7.338974e-01, 7.360555e-01, 7.382053e-01, 7.403467e-01, 7.424797e-01, 7.446045e-01, 7.467209e-01, 7.488291e-01, 7.509291e-01, 7.530208e-01, 7.551044e-01, 7.571798e-01, 7.592472e-01, 7.613064e-01, 7.633576e-01, 7.654008e-01, 7.674360e-01, 7.694633e-01, 7.714826e-01, 7.734940e-01, 7.754975e-01, 7.774932e-01, 7.794811e-01, 7.814612e-01, 7.834335e-01, 7.853983e-01, 7.853983e-01

};

floatmy_abs(float f)

{

if (f >= 0.0)

{

return f;

}

return -f;

}

REAL fast_atan2(REAL y, REAL x) {

REAL x_abs, y_abs, z;REAL alpha, angle, base_angle;int index;