| /* |
| $License: |
| Copyright (C) 2011-2012 InvenSense Corporation, All Rights Reserved. |
| See included License.txt for License information. |
| $ |
| */ |
| |
| /******************************************************************************* |
| * |
| * $Id:$ |
| * |
| ******************************************************************************/ |
| |
| /** |
| * @defgroup ML_MATH_FUNC ml_math_func |
| * @brief Motion Library - Math Functions |
| * Common math functions the Motion Library |
| * |
| * @{ |
| * @file ml_math_func.c |
| * @brief Math Functions. |
| */ |
| |
| #include "mlmath.h" |
| #include "ml_math_func.h" |
| #include "mlinclude.h" |
| #include <string.h> |
| |
| /** @internal |
| * Does the cross product of compass by gravity, then converts that |
| * to the world frame using the quaternion, then computes the angle that |
| * is made. |
| * |
| * @param[in] compass Compass Vector (Body Frame), length 3 |
| * @param[in] grav Gravity Vector (Body Frame), length 3 |
| * @param[in] quat Quaternion, Length 4 |
| * @return Angle Cross Product makes after quaternion rotation. |
| */ |
| float inv_compass_angle(const long *compass, const long *grav, const float *quat) |
| { |
| float cgcross[4], q1[4], q2[4], qi[4]; |
| float angW; |
| |
| // Compass cross Gravity |
| cgcross[0] = 0.f; |
| cgcross[1] = (float)compass[1] * grav[2] - (float)compass[2] * grav[1]; |
| cgcross[2] = (float)compass[2] * grav[0] - (float)compass[0] * grav[2]; |
| cgcross[3] = (float)compass[0] * grav[1] - (float)compass[1] * grav[0]; |
| |
| // Now convert cross product into world frame |
| inv_q_multf(quat, cgcross, q1); |
| inv_q_invertf(quat, qi); |
| inv_q_multf(q1, qi, q2); |
| |
| // Protect against atan2 of 0,0 |
| if ((q2[2] == 0.f) && (q2[1] == 0.f)) |
| return 0.f; |
| |
| // This is the unfiltered heading correction |
| angW = -atan2f(q2[2], q2[1]); |
| return angW; |
| } |
| |
| /** |
| * @brief The gyro data magnitude squared : |
| * (1 degree per second)^2 = 2^6 = 2^GYRO_MAG_SQR_SHIFT. |
| * @param[in] gyro Gyro data scaled with 1 dps = 2^16 |
| * @return the computed magnitude squared output of the gyroscope. |
| */ |
| unsigned long inv_get_gyro_sum_of_sqr(const long *gyro) |
| { |
| unsigned long gmag = 0; |
| long temp; |
| int kk; |
| |
| for (kk = 0; kk < 3; ++kk) { |
| temp = gyro[kk] >> (16 - (GYRO_MAG_SQR_SHIFT / 2)); |
| gmag += temp * temp; |
| } |
| |
| return gmag; |
| } |
| |
| /** Performs a multiply and shift by 29. These are good functions to write in assembly on |
| * with devices with small memory where you want to get rid of the long long which some |
| * assemblers don't handle well |
| * @param[in] a |
| * @param[in] b |
| * @return ((long long)a*b)>>29 |
| */ |
| long inv_q29_mult(long a, long b) |
| { |
| #ifdef UMPL_ELIMINATE_64BIT |
| long result; |
| result = (long)((float)a * b / (1L << 29)); |
| return result; |
| #else |
| long long temp; |
| long result; |
| temp = (long long)a * b; |
| result = (long)(temp >> 29); |
| return result; |
| #endif |
| } |
| |
| /** Performs a multiply and shift by 30. These are good functions to write in assembly on |
| * with devices with small memory where you want to get rid of the long long which some |
| * assemblers don't handle well |
| * @param[in] a |
| * @param[in] b |
| * @return ((long long)a*b)>>30 |
| */ |
| long inv_q30_mult(long a, long b) |
| { |
| #ifdef UMPL_ELIMINATE_64BIT |
| long result; |
| result = (long)((float)a * b / (1L << 30)); |
| return result; |
| #else |
| long long temp; |
| long result; |
| temp = (long long)a * b; |
| result = (long)(temp >> 30); |
| return result; |
| #endif |
| } |
| |
| #ifndef UMPL_ELIMINATE_64BIT |
| long inv_q30_div(long a, long b) |
| { |
| long long temp; |
| long result; |
| temp = (((long long)a) << 30) / b; |
| result = (long)temp; |
| return result; |
| } |
| #endif |
| |
| /** Performs a multiply and shift by shift. These are good functions to write |
| * in assembly on with devices with small memory where you want to get rid of |
| * the long long which some assemblers don't handle well |
| * @param[in] a First multicand |
| * @param[in] b Second multicand |
| * @param[in] shift Shift amount after multiplying |
| * @return ((long long)a*b)<<shift |
| */ |
| #ifndef UMPL_ELIMINATE_64BIT |
| long inv_q_shift_mult(long a, long b, int shift) |
| { |
| long result; |
| result = (long)(((long long)a * b) >> shift); |
| return result; |
| } |
| #endif |
| |
| /** Performs a fixed point quaternion multiply. |
| * @param[in] q1 First Quaternion Multicand, length 4. 1.0 scaled |
| * to 2^30 |
| * @param[in] q2 Second Quaternion Multicand, length 4. 1.0 scaled |
| * to 2^30 |
| * @param[out] qProd Product after quaternion multiply. Length 4. |
| * 1.0 scaled to 2^30. |
| */ |
| void inv_q_mult(const long *q1, const long *q2, long *qProd) |
| { |
| INVENSENSE_FUNC_START; |
| qProd[0] = inv_q30_mult(q1[0], q2[0]) - inv_q30_mult(q1[1], q2[1]) - |
| inv_q30_mult(q1[2], q2[2]) - inv_q30_mult(q1[3], q2[3]); |
| |
| qProd[1] = inv_q30_mult(q1[0], q2[1]) + inv_q30_mult(q1[1], q2[0]) + |
| inv_q30_mult(q1[2], q2[3]) - inv_q30_mult(q1[3], q2[2]); |
| |
| qProd[2] = inv_q30_mult(q1[0], q2[2]) - inv_q30_mult(q1[1], q2[3]) + |
| inv_q30_mult(q1[2], q2[0]) + inv_q30_mult(q1[3], q2[1]); |
| |
| qProd[3] = inv_q30_mult(q1[0], q2[3]) + inv_q30_mult(q1[1], q2[2]) - |
| inv_q30_mult(q1[2], q2[1]) + inv_q30_mult(q1[3], q2[0]); |
| } |
| |
| /** Performs a fixed point quaternion addition. |
| * @param[in] q1 First Quaternion term, length 4. 1.0 scaled |
| * to 2^30 |
| * @param[in] q2 Second Quaternion term, length 4. 1.0 scaled |
| * to 2^30 |
| * @param[out] qSum Sum after quaternion summation. Length 4. |
| * 1.0 scaled to 2^30. |
| */ |
| void inv_q_add(long *q1, long *q2, long *qSum) |
| { |
| INVENSENSE_FUNC_START; |
| qSum[0] = q1[0] + q2[0]; |
| qSum[1] = q1[1] + q2[1]; |
| qSum[2] = q1[2] + q2[2]; |
| qSum[3] = q1[3] + q2[3]; |
| } |
| |
| void inv_vector_normalize(long *vec, int length) |
| { |
| INVENSENSE_FUNC_START; |
| double normSF = 0; |
| int ii; |
| for (ii = 0; ii < length; ii++) { |
| normSF += |
| inv_q30_to_double(vec[ii]) * inv_q30_to_double(vec[ii]); |
| } |
| if (normSF > 0) { |
| normSF = 1 / sqrt(normSF); |
| for (ii = 0; ii < length; ii++) { |
| vec[ii] = (int)((double)vec[ii] * normSF); |
| } |
| } else { |
| vec[0] = 1073741824L; |
| for (ii = 1; ii < length; ii++) { |
| vec[ii] = 0; |
| } |
| } |
| } |
| |
| void inv_q_normalize(long *q) |
| { |
| INVENSENSE_FUNC_START; |
| inv_vector_normalize(q, 4); |
| } |
| |
| void inv_q_invert(const long *q, long *qInverted) |
| { |
| INVENSENSE_FUNC_START; |
| qInverted[0] = q[0]; |
| qInverted[1] = -q[1]; |
| qInverted[2] = -q[2]; |
| qInverted[3] = -q[3]; |
| } |
| |
| double quaternion_to_rotation_angle(const long *quat) { |
| double quat0 = (double )quat[0] / 1073741824; |
| if (quat0 > 1.0f) { |
| quat0 = 1.0; |
| } else if (quat0 < -1.0f) { |
| quat0 = -1.0; |
| } |
| |
| return acos(quat0)*2*180/M_PI; |
| } |
| |
| /** Rotates a 3-element vector by Rotation defined by Q |
| */ |
| void inv_q_rotate(const long *q, const long *in, long *out) |
| { |
| long q_temp1[4], q_temp2[4]; |
| long in4[4], out4[4]; |
| |
| // Fixme optimize |
| in4[0] = 0; |
| memcpy(&in4[1], in, 3 * sizeof(long)); |
| inv_q_mult(q, in4, q_temp1); |
| inv_q_invert(q, q_temp2); |
| inv_q_mult(q_temp1, q_temp2, out4); |
| memcpy(out, &out4[1], 3 * sizeof(long)); |
| } |
| |
| void inv_q_multf(const float *q1, const float *q2, float *qProd) |
| { |
| INVENSENSE_FUNC_START; |
| qProd[0] = |
| (q1[0] * q2[0] - q1[1] * q2[1] - q1[2] * q2[2] - q1[3] * q2[3]); |
| qProd[1] = |
| (q1[0] * q2[1] + q1[1] * q2[0] + q1[2] * q2[3] - q1[3] * q2[2]); |
| qProd[2] = |
| (q1[0] * q2[2] - q1[1] * q2[3] + q1[2] * q2[0] + q1[3] * q2[1]); |
| qProd[3] = |
| (q1[0] * q2[3] + q1[1] * q2[2] - q1[2] * q2[1] + q1[3] * q2[0]); |
| } |
| |
| void inv_q_addf(const float *q1, const float *q2, float *qSum) |
| { |
| INVENSENSE_FUNC_START; |
| qSum[0] = q1[0] + q2[0]; |
| qSum[1] = q1[1] + q2[1]; |
| qSum[2] = q1[2] + q2[2]; |
| qSum[3] = q1[3] + q2[3]; |
| } |
| |
| void inv_q_normalizef(float *q) |
| { |
| INVENSENSE_FUNC_START; |
| float normSF = 0; |
| float xHalf = 0; |
| normSF = (q[0] * q[0] + q[1] * q[1] + q[2] * q[2] + q[3] * q[3]); |
| if (normSF < 2) { |
| xHalf = 0.5f * normSF; |
| normSF = normSF * (1.5f - xHalf * normSF * normSF); |
| normSF = normSF * (1.5f - xHalf * normSF * normSF); |
| normSF = normSF * (1.5f - xHalf * normSF * normSF); |
| normSF = normSF * (1.5f - xHalf * normSF * normSF); |
| q[0] *= normSF; |
| q[1] *= normSF; |
| q[2] *= normSF; |
| q[3] *= normSF; |
| } else { |
| q[0] = 1.0; |
| q[1] = 0.0; |
| q[2] = 0.0; |
| q[3] = 0.0; |
| } |
| normSF = (q[0] * q[0] + q[1] * q[1] + q[2] * q[2] + q[3] * q[3]); |
| } |
| |
| /** Performs a length 4 vector normalization with a square root. |
| * @param[in,out] q vector to normalize. Returns [1,0,0,0] is magnitude is zero. |
| */ |
| void inv_q_norm4(float *q) |
| { |
| float mag; |
| mag = sqrtf(q[0] * q[0] + q[1] * q[1] + q[2] * q[2] + q[3] * q[3]); |
| if (mag) { |
| q[0] /= mag; |
| q[1] /= mag; |
| q[2] /= mag; |
| q[3] /= mag; |
| } else { |
| q[0] = 1.f; |
| q[1] = 0.f; |
| q[2] = 0.f; |
| q[3] = 0.f; |
| } |
| } |
| |
| void inv_q_invertf(const float *q, float *qInverted) |
| { |
| INVENSENSE_FUNC_START; |
| qInverted[0] = q[0]; |
| qInverted[1] = -q[1]; |
| qInverted[2] = -q[2]; |
| qInverted[3] = -q[3]; |
| } |
| |
| /** |
| * Converts a quaternion to a rotation matrix. |
| * @param[in] quat 4-element quaternion in fixed point. One is 2^30. |
| * @param[out] rot Rotation matrix in fixed point. One is 2^30. The |
| * First 3 elements of the rotation matrix, represent |
| * the first row of the matrix. Rotation matrix multiplied |
| * by a 3 element column vector transform a vector from Body |
| * to World. |
| */ |
| void inv_quaternion_to_rotation(const long *quat, long *rot) |
| { |
| rot[0] = |
| inv_q29_mult(quat[1], quat[1]) + inv_q29_mult(quat[0], |
| quat[0]) - |
| 1073741824L; |
| rot[1] = |
| inv_q29_mult(quat[1], quat[2]) - inv_q29_mult(quat[3], quat[0]); |
| rot[2] = |
| inv_q29_mult(quat[1], quat[3]) + inv_q29_mult(quat[2], quat[0]); |
| rot[3] = |
| inv_q29_mult(quat[1], quat[2]) + inv_q29_mult(quat[3], quat[0]); |
| rot[4] = |
| inv_q29_mult(quat[2], quat[2]) + inv_q29_mult(quat[0], |
| quat[0]) - |
| 1073741824L; |
| rot[5] = |
| inv_q29_mult(quat[2], quat[3]) - inv_q29_mult(quat[1], quat[0]); |
| rot[6] = |
| inv_q29_mult(quat[1], quat[3]) - inv_q29_mult(quat[2], quat[0]); |
| rot[7] = |
| inv_q29_mult(quat[2], quat[3]) + inv_q29_mult(quat[1], quat[0]); |
| rot[8] = |
| inv_q29_mult(quat[3], quat[3]) + inv_q29_mult(quat[0], |
| quat[0]) - |
| 1073741824L; |
| } |
| |
| /** |
| * Converts a quaternion to a rotation vector. A rotation vector is |
| * a method to represent a 4-element quaternion vector in 3-elements. |
| * To get the quaternion from the 3-elements, The last 3-elements of |
| * the quaternion will be the given rotation vector. The first element |
| * of the quaternion will be the positive value that will be required |
| * to make the magnitude of the quaternion 1.0 or 2^30 in fixed point units. |
| * @param[in] quat 4-element quaternion in fixed point. One is 2^30. |
| * @param[out] rot Rotation vector in fixed point. One is 2^30. |
| */ |
| void inv_quaternion_to_rotation_vector(const long *quat, long *rot) |
| { |
| rot[0] = quat[1]; |
| rot[1] = quat[2]; |
| rot[2] = quat[3]; |
| |
| if (quat[0] < 0.0) { |
| rot[0] = -rot[0]; |
| rot[1] = -rot[1]; |
| rot[2] = -rot[2]; |
| } |
| } |
| |
| /** Converts a 32-bit long to a big endian byte stream */ |
| unsigned char *inv_int32_to_big8(long x, unsigned char *big8) |
| { |
| big8[0] = (unsigned char)((x >> 24) & 0xff); |
| big8[1] = (unsigned char)((x >> 16) & 0xff); |
| big8[2] = (unsigned char)((x >> 8) & 0xff); |
| big8[3] = (unsigned char)(x & 0xff); |
| return big8; |
| } |
| |
| /** Converts a big endian byte stream into a 32-bit long */ |
| long inv_big8_to_int32(const unsigned char *big8) |
| { |
| long x; |
| x = ((long)big8[0] << 24) | ((long)big8[1] << 16) | ((long)big8[2] << 8) |
| | ((long)big8[3]); |
| return x; |
| } |
| |
| /** Converts a big endian byte stream into a 16-bit integer (short) */ |
| short inv_big8_to_int16(const unsigned char *big8) |
| { |
| short x; |
| x = ((short)big8[0] << 8) | ((short)big8[1]); |
| return x; |
| } |
| |
| /** Converts a little endian byte stream into a 16-bit integer (short) */ |
| short inv_little8_to_int16(const unsigned char *little8) |
| { |
| short x; |
| x = ((short)little8[1] << 8) | ((short)little8[0]); |
| return x; |
| } |
| |
| /** Converts a 16-bit short to a big endian byte stream */ |
| unsigned char *inv_int16_to_big8(short x, unsigned char *big8) |
| { |
| big8[0] = (unsigned char)((x >> 8) & 0xff); |
| big8[1] = (unsigned char)(x & 0xff); |
| return big8; |
| } |
| |
| void inv_matrix_det_inc(float *a, float *b, int *n, int x, int y) |
| { |
| int k, l, i, j; |
| for (i = 0, k = 0; i < *n; i++, k++) { |
| for (j = 0, l = 0; j < *n; j++, l++) { |
| if (i == x) |
| i++; |
| if (j == y) |
| j++; |
| *(b + 6 * k + l) = *(a + 6 * i + j); |
| } |
| } |
| *n = *n - 1; |
| } |
| |
| void inv_matrix_det_incd(double *a, double *b, int *n, int x, int y) |
| { |
| int k, l, i, j; |
| for (i = 0, k = 0; i < *n; i++, k++) { |
| for (j = 0, l = 0; j < *n; j++, l++) { |
| if (i == x) |
| i++; |
| if (j == y) |
| j++; |
| *(b + 6 * k + l) = *(a + 6 * i + j); |
| } |
| } |
| *n = *n - 1; |
| } |
| |
| float inv_matrix_det(float *p, int *n) |
| { |
| float d[6][6], sum = 0; |
| int i, j, m; |
| m = *n; |
| if (*n == 2) |
| return (*p ** (p + 7) - *(p + 1) ** (p + 6)); |
| for (i = 0, j = 0; j < m; j++) { |
| *n = m; |
| inv_matrix_det_inc(p, &d[0][0], n, i, j); |
| sum = |
| sum + *(p + 6 * i + j) * SIGNM(i + |
| j) * |
| inv_matrix_det(&d[0][0], n); |
| } |
| |
| return (sum); |
| } |
| |
| double inv_matrix_detd(double *p, int *n) |
| { |
| double d[6][6], sum = 0; |
| int i, j, m; |
| m = *n; |
| if (*n == 2) |
| return (*p ** (p + 7) - *(p + 1) ** (p + 6)); |
| for (i = 0, j = 0; j < m; j++) { |
| *n = m; |
| inv_matrix_det_incd(p, &d[0][0], n, i, j); |
| sum = |
| sum + *(p + 6 * i + j) * SIGNM(i + |
| j) * |
| inv_matrix_detd(&d[0][0], n); |
| } |
| |
| return (sum); |
| } |
| |
| /** Wraps angle from (-M_PI,M_PI] |
| * @param[in] ang Angle in radians to wrap |
| * @return Wrapped angle from (-M_PI,M_PI] |
| */ |
| float inv_wrap_angle(float ang) |
| { |
| if (ang > M_PI) |
| return ang - 2 * (float)M_PI; |
| else if (ang <= -(float)M_PI) |
| return ang + 2 * (float)M_PI; |
| else |
| return ang; |
| } |
| |
| /** Finds the minimum angle difference ang1-ang2 such that difference |
| * is between [-M_PI,M_PI] |
| * @param[in] ang1 |
| * @param[in] ang2 |
| * @return angle difference ang1-ang2 |
| */ |
| float inv_angle_diff(float ang1, float ang2) |
| { |
| float d; |
| ang1 = inv_wrap_angle(ang1); |
| ang2 = inv_wrap_angle(ang2); |
| d = ang1 - ang2; |
| if (d > M_PI) |
| d -= 2 * (float)M_PI; |
| else if (d < -(float)M_PI) |
| d += 2 * (float)M_PI; |
| return d; |
| } |
| |
| /** bernstein hash, derived from public domain source */ |
| uint32_t inv_checksum(const unsigned char *str, int len) |
| { |
| uint32_t hash = 5381; |
| int i, c; |
| |
| for (i = 0; i < len; i++) { |
| c = *(str + i); |
| hash = ((hash << 5) + hash) + c; /* hash * 33 + c */ |
| } |
| |
| return hash; |
| } |
| |
| static unsigned short inv_row_2_scale(const signed char *row) |
| { |
| unsigned short b; |
| |
| if (row[0] > 0) |
| b = 0; |
| else if (row[0] < 0) |
| b = 4; |
| else if (row[1] > 0) |
| b = 1; |
| else if (row[1] < 0) |
| b = 5; |
| else if (row[2] > 0) |
| b = 2; |
| else if (row[2] < 0) |
| b = 6; |
| else |
| b = 7; // error |
| return b; |
| } |
| |
| |
| /** Converts an orientation matrix made up of 0,+1,and -1 to a scalar representation. |
| * @param[in] mtx Orientation matrix to convert to a scalar. |
| * @return Description of orientation matrix. The lowest 2 bits (0 and 1) represent the column the one is on for the |
| * first row, with the bit number 2 being the sign. The next 2 bits (3 and 4) represent |
| * the column the one is on for the second row with bit number 5 being the sign. |
| * The next 2 bits (6 and 7) represent the column the one is on for the third row with |
| * bit number 8 being the sign. In binary the identity matrix would therefor be: |
| * 010_001_000 or 0x88 in hex. |
| */ |
| unsigned short inv_orientation_matrix_to_scalar(const signed char *mtx) |
| { |
| |
| unsigned short scalar; |
| |
| /* |
| XYZ 010_001_000 Identity Matrix |
| XZY 001_010_000 |
| YXZ 010_000_001 |
| YZX 000_010_001 |
| ZXY 001_000_010 |
| ZYX 000_001_010 |
| */ |
| |
| scalar = inv_row_2_scale(mtx); |
| scalar |= inv_row_2_scale(mtx + 3) << 3; |
| scalar |= inv_row_2_scale(mtx + 6) << 6; |
| |
| |
| return scalar; |
| } |
| |
| /** Uses the scalar orientation value to convert from chip frame to body frame |
| * @param[in] orientation A scalar that represent how to go from chip to body frame |
| * @param[in] input Input vector, length 3 |
| * @param[out] output Output vector, length 3 |
| */ |
| void inv_convert_to_body(unsigned short orientation, const long *input, long *output) |
| { |
| output[0] = input[orientation & 0x03] * SIGNSET(orientation & 0x004); |
| output[1] = input[(orientation>>3) & 0x03] * SIGNSET(orientation & 0x020); |
| output[2] = input[(orientation>>6) & 0x03] * SIGNSET(orientation & 0x100); |
| } |
| |
| /** Uses the scalar orientation value to convert from body frame to chip frame |
| * @param[in] orientation A scalar that represent how to go from chip to body frame |
| * @param[in] input Input vector, length 3 |
| * @param[out] output Output vector, length 3 |
| */ |
| void inv_convert_to_chip(unsigned short orientation, const long *input, long *output) |
| { |
| output[orientation & 0x03] = input[0] * SIGNSET(orientation & 0x004); |
| output[(orientation>>3) & 0x03] = input[1] * SIGNSET(orientation & 0x020); |
| output[(orientation>>6) & 0x03] = input[2] * SIGNSET(orientation & 0x100); |
| } |
| |
| |
| /** Uses the scalar orientation value to convert from chip frame to body frame and |
| * apply appropriate scaling. |
| * @param[in] orientation A scalar that represent how to go from chip to body frame |
| * @param[in] sensitivity Sensitivity scale |
| * @param[in] input Input vector, length 3 |
| * @param[out] output Output vector, length 3 |
| */ |
| void inv_convert_to_body_with_scale(unsigned short orientation, long sensitivity, const long *input, long *output) |
| { |
| output[0] = inv_q30_mult(input[orientation & 0x03] * |
| SIGNSET(orientation & 0x004), sensitivity); |
| output[1] = inv_q30_mult(input[(orientation>>3) & 0x03] * |
| SIGNSET(orientation & 0x020), sensitivity); |
| output[2] = inv_q30_mult(input[(orientation>>6) & 0x03] * |
| SIGNSET(orientation & 0x100), sensitivity); |
| } |
| |
| /** find a norm for a vector |
| * @param[in] x a vector [3x1] |
| * @return the normalize vector. |
| */ |
| double inv_vector_norm(const float *x) |
| { |
| return sqrt(x[0]*x[0]+x[1]*x[1]+x[2]*x[2]); |
| } |
| |
| void inv_init_biquad_filter(inv_biquad_filter_t *pFilter, float *pBiquadCoeff) { |
| int i; |
| // initial state to zero |
| pFilter->state[0] = 0; |
| pFilter->state[1] = 0; |
| |
| // set up coefficients |
| for (i=0; i<5; i++) { |
| pFilter->c[i] = pBiquadCoeff[i]; |
| } |
| } |
| |
| void inv_calc_state_to_match_output(inv_biquad_filter_t *pFilter, float input) |
| { |
| pFilter->input = input; |
| pFilter->output = input; |
| pFilter->state[0] = input / (1 + pFilter->c[2] + pFilter->c[3]); |
| pFilter->state[1] = pFilter->state[0]; |
| } |
| |
| float inv_biquad_filter_process(inv_biquad_filter_t *pFilter, float input) { |
| float stateZero; |
| |
| pFilter->input = input; |
| // calculate the new state; |
| stateZero = pFilter->input - pFilter->c[2]*pFilter->state[0] |
| - pFilter->c[3]*pFilter->state[1]; |
| |
| pFilter->output = stateZero + pFilter->c[0]*pFilter->state[0] |
| + pFilter->c[1]*pFilter->state[1]; |
| |
| // update the output and state |
| pFilter->output = pFilter->output * pFilter->c[4]; |
| pFilter->state[1] = pFilter->state[0]; |
| pFilter->state[0] = stateZero; |
| return pFilter->output; |
| } |
| |
| void inv_get_cross_product_vec(float *cgcross, float compass[3], float grav[3]) { |
| |
| cgcross[0] = (float)compass[1] * grav[2] - (float)compass[2] * grav[1]; |
| cgcross[1] = (float)compass[2] * grav[0] - (float)compass[0] * grav[2]; |
| cgcross[2] = (float)compass[0] * grav[1] - (float)compass[1] * grav[0]; |
| } |
| |
| /** |
| * @} |
| */ |
