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esphome/esphome/components/sgp40/sensirion_voc_algorithm.cpp
Otto Winter 360effcb72
Activate some clang-tidy checks (#1884)
2021-06-10 13:04:40 +02:00

628 lines
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#include "sensirion_voc_algorithm.h"
namespace esphome {
namespace sgp40 {
/* The VOC code were originally created by
* https://github.com/Sensirion/embedded-sgp
* The fixed point arithmetic parts of this code were originally created by
* https://github.com/PetteriAimonen/libfixmath
*/
/*!< the maximum value of fix16_t */
#define FIX16_MAXIMUM 0x7FFFFFFF
/*!< the minimum value of fix16_t */
static const uint32_t FIX16_MINIMUM = 0x80000000;
/*!< the value used to indicate overflows when FIXMATH_NO_OVERFLOW is not
* specified */
static const uint32_t FIX16_OVERFLOW = 0x80000000;
/*!< fix16_t value of 1 */
const uint32_t FIX16_ONE = 0x00010000;
inline fix16_t fix16_from_int(int32_t a) { return a * FIX16_ONE; }
inline int32_t fix16_cast_to_int(fix16_t a) { return (a >> 16); }
/*! Multiplies the two given fix16_t's and returns the result. */
static fix16_t fix16_mul(fix16_t in_arg0, fix16_t in_arg1);
/*! Divides the first given fix16_t by the second and returns the result. */
static fix16_t fix16_div(fix16_t a, fix16_t b);
/*! Returns the square root of the given fix16_t. */
static fix16_t fix16_sqrt(fix16_t in_value);
/*! Returns the exponent (e^) of the given fix16_t. */
static fix16_t fix16_exp(fix16_t in_value);
static fix16_t fix16_mul(fix16_t in_arg0, fix16_t in_arg1) {
// Each argument is divided to 16-bit parts.
// AB
// * CD
// -----------
// BD 16 * 16 -> 32 bit products
// CB
// AD
// AC
// |----| 64 bit product
int32_t a = (in_arg0 >> 16), c = (in_arg1 >> 16);
uint32_t b = (in_arg0 & 0xFFFF), d = (in_arg1 & 0xFFFF);
int32_t ac = a * c;
int32_t ad_cb = a * d + c * b;
uint32_t bd = b * d;
int32_t product_hi = ac + (ad_cb >> 16); // NOLINT
// Handle carry from lower 32 bits to upper part of result.
uint32_t ad_cb_temp = ad_cb << 16; // NOLINT
uint32_t product_lo = bd + ad_cb_temp;
if (product_lo < bd)
product_hi++;
#ifndef FIXMATH_NO_OVERFLOW
// The upper 17 bits should all be the same (the sign).
if (product_hi >> 31 != product_hi >> 15)
return FIX16_OVERFLOW;
#endif
#ifdef FIXMATH_NO_ROUNDING
return (product_hi << 16) | (product_lo >> 16);
#else
// Subtracting 0x8000 (= 0.5) and then using signed right shift
// achieves proper rounding to result-1, except in the corner
// case of negative numbers and lowest word = 0x8000.
// To handle that, we also have to subtract 1 for negative numbers.
uint32_t product_lo_tmp = product_lo;
product_lo -= 0x8000;
product_lo -= (uint32_t) product_hi >> 31;
if (product_lo > product_lo_tmp)
product_hi--;
// Discard the lowest 16 bits. Note that this is not exactly the same
// as dividing by 0x10000. For example if product = -1, result will
// also be -1 and not 0. This is compensated by adding +1 to the result
// and compensating this in turn in the rounding above.
fix16_t result = (product_hi << 16) | (product_lo >> 16); // NOLINT
result += 1;
return result;
#endif
}
static fix16_t fix16_div(fix16_t a, fix16_t b) {
// This uses the basic binary restoring division algorithm.
// It appears to be faster to do the whole division manually than
// trying to compose a 64-bit divide out of 32-bit divisions on
// platforms without hardware divide.
if (b == 0)
return FIX16_MINIMUM;
uint32_t remainder = (a >= 0) ? a : (-a);
uint32_t divider = (b >= 0) ? b : (-b);
uint32_t quotient = 0;
uint32_t bit = 0x10000;
/* The algorithm requires D >= R */
while (divider < remainder) {
divider <<= 1;
bit <<= 1;
}
#ifndef FIXMATH_NO_OVERFLOW
if (!bit)
return FIX16_OVERFLOW;
#endif
if (divider & 0x80000000) {
// Perform one step manually to avoid overflows later.
// We know that divider's bottom bit is 0 here.
if (remainder >= divider) {
quotient |= bit;
remainder -= divider;
}
divider >>= 1;
bit >>= 1;
}
/* Main division loop */
while (bit && remainder) {
if (remainder >= divider) {
quotient |= bit;
remainder -= divider;
}
remainder <<= 1;
bit >>= 1;
}
#ifndef FIXMATH_NO_ROUNDING
if (remainder >= divider) {
quotient++;
}
#endif
fix16_t result = quotient;
/* Figure out the sign of result */
if ((a ^ b) & 0x80000000) {
#ifndef FIXMATH_NO_OVERFLOW
if (result == FIX16_MINIMUM)
return FIX16_OVERFLOW;
#endif
result = -result;
}
return result;
}
static fix16_t fix16_sqrt(fix16_t in_value) {
// It is assumed that x is not negative
uint32_t num = in_value;
uint32_t result = 0;
uint32_t bit;
uint8_t n;
bit = (uint32_t) 1 << 30;
while (bit > num)
bit >>= 2;
// The main part is executed twice, in order to avoid
// using 64 bit values in computations.
for (n = 0; n < 2; n++) {
// First we get the top 24 bits of the answer.
while (bit) {
if (num >= result + bit) {
num -= result + bit;
result = (result >> 1) + bit;
} else {
result = (result >> 1);
}
bit >>= 2;
}
if (n == 0) {
// Then process it again to get the lowest 8 bits.
if (num > 65535) {
// The remainder 'num' is too large to be shifted left
// by 16, so we have to add 1 to result manually and
// adjust 'num' accordingly.
// num = a - (result + 0.5)^2
// = num + result^2 - (result + 0.5)^2
// = num - result - 0.5
num -= result;
num = (num << 16) - 0x8000;
result = (result << 16) + 0x8000;
} else {
num <<= 16;
result <<= 16;
}
bit = 1 << 14;
}
}
#ifndef FIXMATH_NO_ROUNDING
// Finally, if next bit would have been 1, round the result upwards.
if (num > result) {
result++;
}
#endif
return (fix16_t) result;
}
static fix16_t fix16_exp(fix16_t in_value) {
// Function to approximate exp(); optimized more for code size than speed
// exp(x) for x = +/- {1, 1/8, 1/64, 1/512}
fix16_t x = in_value;
static const uint8_t NUM_EXP_VALUES = 4;
static const fix16_t EXP_POS_VALUES[4] = {F16(2.7182818), F16(1.1331485), F16(1.0157477), F16(1.0019550)};
static const fix16_t EXP_NEG_VALUES[4] = {F16(0.3678794), F16(0.8824969), F16(0.9844964), F16(0.9980488)};
const fix16_t *exp_values;
fix16_t res, arg;
uint16_t i;
if (x >= F16(10.3972))
return FIX16_MAXIMUM;
if (x <= F16(-11.7835))
return 0;
if (x < 0) {
x = -x;
exp_values = EXP_NEG_VALUES;
} else {
exp_values = EXP_POS_VALUES;
}
res = FIX16_ONE;
arg = FIX16_ONE;
for (i = 0; i < NUM_EXP_VALUES; i++) {
while (x >= arg) {
res = fix16_mul(res, exp_values[i]);
x -= arg;
}
arg >>= 3;
}
return res;
}
static void voc_algorithm_init_instances(VocAlgorithmParams *params);
static void voc_algorithm_mean_variance_estimator_init(VocAlgorithmParams *params);
static void voc_algorithm_mean_variance_estimator_init_instances(VocAlgorithmParams *params);
static void voc_algorithm_mean_variance_estimator_set_parameters(VocAlgorithmParams *params, fix16_t std_initial,
fix16_t tau_mean_variance_hours,
fix16_t gating_max_duration_minutes);
static void voc_algorithm_mean_variance_estimator_set_states(VocAlgorithmParams *params, fix16_t mean, fix16_t std,
fix16_t uptime_gamma);
static fix16_t voc_algorithm_mean_variance_estimator_get_std(VocAlgorithmParams *params);
static fix16_t voc_algorithm_mean_variance_estimator_get_mean(VocAlgorithmParams *params);
static void voc_algorithm_mean_variance_estimator_calculate_gamma(VocAlgorithmParams *params,
fix16_t voc_index_from_prior);
static void voc_algorithm_mean_variance_estimator_process(VocAlgorithmParams *params, fix16_t sraw,
fix16_t voc_index_from_prior);
static void voc_algorithm_mean_variance_estimator_sigmoid_init(VocAlgorithmParams *params);
static void voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(VocAlgorithmParams *params, fix16_t l,
fix16_t x0, fix16_t k);
static fix16_t voc_algorithm_mean_variance_estimator_sigmoid_process(VocAlgorithmParams *params, fix16_t sample);
static void voc_algorithm_mox_model_init(VocAlgorithmParams *params);
static void voc_algorithm_mox_model_set_parameters(VocAlgorithmParams *params, fix16_t sraw_std, fix16_t sraw_mean);
static fix16_t voc_algorithm_mox_model_process(VocAlgorithmParams *params, fix16_t sraw);
static void voc_algorithm_sigmoid_scaled_init(VocAlgorithmParams *params);
static void voc_algorithm_sigmoid_scaled_set_parameters(VocAlgorithmParams *params, fix16_t offset);
static fix16_t voc_algorithm_sigmoid_scaled_process(VocAlgorithmParams *params, fix16_t sample);
static void voc_algorithm_adaptive_lowpass_init(VocAlgorithmParams *params);
static void voc_algorithm_adaptive_lowpass_set_parameters(VocAlgorithmParams *params);
static fix16_t voc_algorithm_adaptive_lowpass_process(VocAlgorithmParams *params, fix16_t sample);
void voc_algorithm_init(VocAlgorithmParams *params) {
params->mVoc_Index_Offset = F16(VOC_ALGORITHM_VOC_INDEX_OFFSET_DEFAULT);
params->mTau_Mean_Variance_Hours = F16(VOC_ALGORITHM_TAU_MEAN_VARIANCE_HOURS);
params->mGating_Max_Duration_Minutes = F16(VOC_ALGORITHM_GATING_MAX_DURATION_MINUTES);
params->mSraw_Std_Initial = F16(VOC_ALGORITHM_SRAW_STD_INITIAL);
params->mUptime = F16(0.);
params->mSraw = F16(0.);
params->mVoc_Index = 0;
voc_algorithm_init_instances(params);
}
static void voc_algorithm_init_instances(VocAlgorithmParams *params) {
voc_algorithm_mean_variance_estimator_init(params);
voc_algorithm_mean_variance_estimator_set_parameters(
params, params->mSraw_Std_Initial, params->mTau_Mean_Variance_Hours, params->mGating_Max_Duration_Minutes);
voc_algorithm_mox_model_init(params);
voc_algorithm_mox_model_set_parameters(params, voc_algorithm_mean_variance_estimator_get_std(params),
voc_algorithm_mean_variance_estimator_get_mean(params));
voc_algorithm_sigmoid_scaled_init(params);
voc_algorithm_sigmoid_scaled_set_parameters(params, params->mVoc_Index_Offset);
voc_algorithm_adaptive_lowpass_init(params);
voc_algorithm_adaptive_lowpass_set_parameters(params);
}
void voc_algorithm_get_states(VocAlgorithmParams *params, int32_t *state0, int32_t *state1) {
*state0 = voc_algorithm_mean_variance_estimator_get_mean(params);
*state1 = voc_algorithm_mean_variance_estimator_get_std(params);
}
void voc_algorithm_set_states(VocAlgorithmParams *params, int32_t state0, int32_t state1) {
voc_algorithm_mean_variance_estimator_set_states(params, state0, state1, F16(VOC_ALGORITHM_PERSISTENCE_UPTIME_GAMMA));
params->mSraw = state0;
}
void voc_algorithm_set_tuning_parameters(VocAlgorithmParams *params, int32_t voc_index_offset,
int32_t learning_time_hours, int32_t gating_max_duration_minutes,
int32_t std_initial) {
params->mVoc_Index_Offset = (fix16_from_int(voc_index_offset));
params->mTau_Mean_Variance_Hours = (fix16_from_int(learning_time_hours));
params->mGating_Max_Duration_Minutes = (fix16_from_int(gating_max_duration_minutes));
params->mSraw_Std_Initial = (fix16_from_int(std_initial));
voc_algorithm_init_instances(params);
}
void voc_algorithm_process(VocAlgorithmParams *params, int32_t sraw, int32_t *voc_index) {
if ((params->mUptime <= F16(VOC_ALGORITHM_INITIAL_BLACKOUT))) {
params->mUptime = (params->mUptime + F16(VOC_ALGORITHM_SAMPLING_INTERVAL));
} else {
if (((sraw > 0) && (sraw < 65000))) {
if ((sraw < 20001)) {
sraw = 20001;
} else if ((sraw > 52767)) {
sraw = 52767;
}
params->mSraw = (fix16_from_int((sraw - 20000)));
}
params->mVoc_Index = voc_algorithm_mox_model_process(params, params->mSraw);
params->mVoc_Index = voc_algorithm_sigmoid_scaled_process(params, params->mVoc_Index);
params->mVoc_Index = voc_algorithm_adaptive_lowpass_process(params, params->mVoc_Index);
if ((params->mVoc_Index < F16(0.5))) {
params->mVoc_Index = F16(0.5);
}
if ((params->mSraw > F16(0.))) {
voc_algorithm_mean_variance_estimator_process(params, params->mSraw, params->mVoc_Index);
voc_algorithm_mox_model_set_parameters(params, voc_algorithm_mean_variance_estimator_get_std(params),
voc_algorithm_mean_variance_estimator_get_mean(params));
}
}
*voc_index = (fix16_cast_to_int((params->mVoc_Index + F16(0.5))));
}
static void voc_algorithm_mean_variance_estimator_init(VocAlgorithmParams *params) {
voc_algorithm_mean_variance_estimator_set_parameters(params, F16(0.), F16(0.), F16(0.));
voc_algorithm_mean_variance_estimator_init_instances(params);
}
static void voc_algorithm_mean_variance_estimator_init_instances(VocAlgorithmParams *params) {
voc_algorithm_mean_variance_estimator_sigmoid_init(params);
}
static void voc_algorithm_mean_variance_estimator_set_parameters(VocAlgorithmParams *params, fix16_t std_initial,
fix16_t tau_mean_variance_hours,
fix16_t gating_max_duration_minutes) {
params->m_Mean_Variance_Estimator_Gating_Max_Duration_Minutes = gating_max_duration_minutes;
params->m_Mean_Variance_Estimator_Initialized = false;
params->m_Mean_Variance_Estimator_Mean = F16(0.);
params->m_Mean_Variance_Estimator_Sraw_Offset = F16(0.);
params->m_Mean_Variance_Estimator_Std = std_initial;
params->m_Mean_Variance_Estimator_Gamma =
(fix16_div(F16((VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_GAMMA_SCALING * (VOC_ALGORITHM_SAMPLING_INTERVAL / 3600.))),
(tau_mean_variance_hours + F16((VOC_ALGORITHM_SAMPLING_INTERVAL / 3600.)))));
params->m_Mean_Variance_Estimator_Gamma_Initial_Mean =
F16(((VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_GAMMA_SCALING * VOC_ALGORITHM_SAMPLING_INTERVAL) /
(VOC_ALGORITHM_TAU_INITIAL_MEAN + VOC_ALGORITHM_SAMPLING_INTERVAL)));
params->m_Mean_Variance_Estimator_Gamma_Initial_Variance =
F16(((VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_GAMMA_SCALING * VOC_ALGORITHM_SAMPLING_INTERVAL) /
(VOC_ALGORITHM_TAU_INITIAL_VARIANCE + VOC_ALGORITHM_SAMPLING_INTERVAL)));
params->m_Mean_Variance_Estimator_Gamma_Mean = F16(0.);
params->m_Mean_Variance_Estimator_Gamma_Variance = F16(0.);
params->m_Mean_Variance_Estimator_Uptime_Gamma = F16(0.);
params->m_Mean_Variance_Estimator_Uptime_Gating = F16(0.);
params->m_Mean_Variance_Estimator_Gating_Duration_Minutes = F16(0.);
}
static void voc_algorithm_mean_variance_estimator_set_states(VocAlgorithmParams *params, fix16_t mean, fix16_t std,
fix16_t uptime_gamma) {
params->m_Mean_Variance_Estimator_Mean = mean;
params->m_Mean_Variance_Estimator_Std = std;
params->m_Mean_Variance_Estimator_Uptime_Gamma = uptime_gamma;
params->m_Mean_Variance_Estimator_Initialized = true;
}
static fix16_t voc_algorithm_mean_variance_estimator_get_std(VocAlgorithmParams *params) {
return params->m_Mean_Variance_Estimator_Std;
}
static fix16_t voc_algorithm_mean_variance_estimator_get_mean(VocAlgorithmParams *params) {
return (params->m_Mean_Variance_Estimator_Mean + params->m_Mean_Variance_Estimator_Sraw_Offset);
}
static void voc_algorithm_mean_variance_estimator_calculate_gamma(VocAlgorithmParams *params,
fix16_t voc_index_from_prior) {
fix16_t uptime_limit;
fix16_t sigmoid_gamma_mean;
fix16_t gamma_mean;
fix16_t gating_threshold_mean;
fix16_t sigmoid_gating_mean;
fix16_t sigmoid_gamma_variance;
fix16_t gamma_variance;
fix16_t gating_threshold_variance;
fix16_t sigmoid_gating_variance;
uptime_limit = F16((VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_FI_X16_MAX - VOC_ALGORITHM_SAMPLING_INTERVAL));
if ((params->m_Mean_Variance_Estimator_Uptime_Gamma < uptime_limit)) {
params->m_Mean_Variance_Estimator_Uptime_Gamma =
(params->m_Mean_Variance_Estimator_Uptime_Gamma + F16(VOC_ALGORITHM_SAMPLING_INTERVAL));
}
if ((params->m_Mean_Variance_Estimator_Uptime_Gating < uptime_limit)) {
params->m_Mean_Variance_Estimator_Uptime_Gating =
(params->m_Mean_Variance_Estimator_Uptime_Gating + F16(VOC_ALGORITHM_SAMPLING_INTERVAL));
}
voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(params, F16(1.), F16(VOC_ALGORITHM_INIT_DURATION_MEAN),
F16(VOC_ALGORITHM_INIT_TRANSITION_MEAN));
sigmoid_gamma_mean =
voc_algorithm_mean_variance_estimator_sigmoid_process(params, params->m_Mean_Variance_Estimator_Uptime_Gamma);
gamma_mean =
(params->m_Mean_Variance_Estimator_Gamma +
(fix16_mul((params->m_Mean_Variance_Estimator_Gamma_Initial_Mean - params->m_Mean_Variance_Estimator_Gamma),
sigmoid_gamma_mean)));
gating_threshold_mean = (F16(VOC_ALGORITHM_GATING_THRESHOLD) +
(fix16_mul(F16((VOC_ALGORITHM_GATING_THRESHOLD_INITIAL - VOC_ALGORITHM_GATING_THRESHOLD)),
voc_algorithm_mean_variance_estimator_sigmoid_process(
params, params->m_Mean_Variance_Estimator_Uptime_Gating))));
voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(params, F16(1.), gating_threshold_mean,
F16(VOC_ALGORITHM_GATING_THRESHOLD_TRANSITION));
sigmoid_gating_mean = voc_algorithm_mean_variance_estimator_sigmoid_process(params, voc_index_from_prior);
params->m_Mean_Variance_Estimator_Gamma_Mean = (fix16_mul(sigmoid_gating_mean, gamma_mean));
voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(
params, F16(1.), F16(VOC_ALGORITHM_INIT_DURATION_VARIANCE), F16(VOC_ALGORITHM_INIT_TRANSITION_VARIANCE));
sigmoid_gamma_variance =
voc_algorithm_mean_variance_estimator_sigmoid_process(params, params->m_Mean_Variance_Estimator_Uptime_Gamma);
gamma_variance =
(params->m_Mean_Variance_Estimator_Gamma +
(fix16_mul((params->m_Mean_Variance_Estimator_Gamma_Initial_Variance - params->m_Mean_Variance_Estimator_Gamma),
(sigmoid_gamma_variance - sigmoid_gamma_mean))));
gating_threshold_variance =
(F16(VOC_ALGORITHM_GATING_THRESHOLD) +
(fix16_mul(F16((VOC_ALGORITHM_GATING_THRESHOLD_INITIAL - VOC_ALGORITHM_GATING_THRESHOLD)),
voc_algorithm_mean_variance_estimator_sigmoid_process(
params, params->m_Mean_Variance_Estimator_Uptime_Gating))));
voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(params, F16(1.), gating_threshold_variance,
F16(VOC_ALGORITHM_GATING_THRESHOLD_TRANSITION));
sigmoid_gating_variance = voc_algorithm_mean_variance_estimator_sigmoid_process(params, voc_index_from_prior);
params->m_Mean_Variance_Estimator_Gamma_Variance = (fix16_mul(sigmoid_gating_variance, gamma_variance));
params->m_Mean_Variance_Estimator_Gating_Duration_Minutes =
(params->m_Mean_Variance_Estimator_Gating_Duration_Minutes +
(fix16_mul(F16((VOC_ALGORITHM_SAMPLING_INTERVAL / 60.)),
((fix16_mul((F16(1.) - sigmoid_gating_mean), F16((1. + VOC_ALGORITHM_GATING_MAX_RATIO)))) -
F16(VOC_ALGORITHM_GATING_MAX_RATIO)))));
if ((params->m_Mean_Variance_Estimator_Gating_Duration_Minutes < F16(0.))) {
params->m_Mean_Variance_Estimator_Gating_Duration_Minutes = F16(0.);
}
if ((params->m_Mean_Variance_Estimator_Gating_Duration_Minutes >
params->m_Mean_Variance_Estimator_Gating_Max_Duration_Minutes)) {
params->m_Mean_Variance_Estimator_Uptime_Gating = F16(0.);
}
}
static void voc_algorithm_mean_variance_estimator_process(VocAlgorithmParams *params, fix16_t sraw,
fix16_t voc_index_from_prior) {
fix16_t delta_sgp;
fix16_t c;
fix16_t additional_scaling;
if ((!params->m_Mean_Variance_Estimator_Initialized)) {
params->m_Mean_Variance_Estimator_Initialized = true;
params->m_Mean_Variance_Estimator_Sraw_Offset = sraw;
params->m_Mean_Variance_Estimator_Mean = F16(0.);
} else {
if (((params->m_Mean_Variance_Estimator_Mean >= F16(100.)) ||
(params->m_Mean_Variance_Estimator_Mean <= F16(-100.)))) {
params->m_Mean_Variance_Estimator_Sraw_Offset =
(params->m_Mean_Variance_Estimator_Sraw_Offset + params->m_Mean_Variance_Estimator_Mean);
params->m_Mean_Variance_Estimator_Mean = F16(0.);
}
sraw = (sraw - params->m_Mean_Variance_Estimator_Sraw_Offset);
voc_algorithm_mean_variance_estimator_calculate_gamma(params, voc_index_from_prior);
delta_sgp = (fix16_div((sraw - params->m_Mean_Variance_Estimator_Mean),
F16(VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_GAMMA_SCALING)));
if ((delta_sgp < F16(0.))) {
c = (params->m_Mean_Variance_Estimator_Std - delta_sgp);
} else {
c = (params->m_Mean_Variance_Estimator_Std + delta_sgp);
}
additional_scaling = F16(1.);
if ((c > F16(1440.))) {
additional_scaling = F16(4.);
}
params->m_Mean_Variance_Estimator_Std = (fix16_mul(
fix16_sqrt((fix16_mul(additional_scaling, (F16(VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_GAMMA_SCALING) -
params->m_Mean_Variance_Estimator_Gamma_Variance)))),
fix16_sqrt(((fix16_mul(params->m_Mean_Variance_Estimator_Std,
(fix16_div(params->m_Mean_Variance_Estimator_Std,
(fix16_mul(F16(VOC_ALGORITHM_MEAN_VARIANCE_ESTIMATOR_GAMMA_SCALING),
additional_scaling)))))) +
(fix16_mul((fix16_div((fix16_mul(params->m_Mean_Variance_Estimator_Gamma_Variance, delta_sgp)),
additional_scaling)),
delta_sgp))))));
params->m_Mean_Variance_Estimator_Mean =
(params->m_Mean_Variance_Estimator_Mean + (fix16_mul(params->m_Mean_Variance_Estimator_Gamma_Mean, delta_sgp)));
}
}
static void voc_algorithm_mean_variance_estimator_sigmoid_init(VocAlgorithmParams *params) {
voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(params, F16(0.), F16(0.), F16(0.));
}
static void voc_algorithm_mean_variance_estimator_sigmoid_set_parameters(VocAlgorithmParams *params, fix16_t l,
fix16_t x0, fix16_t k) {
params->m_Mean_Variance_Estimator_Sigmoid_L = l;
params->m_Mean_Variance_Estimator_Sigmoid_K = k;
params->m_Mean_Variance_Estimator_Sigmoid_X0 = x0;
}
static fix16_t voc_algorithm_mean_variance_estimator_sigmoid_process(VocAlgorithmParams *params, fix16_t sample) {
fix16_t x;
x = (fix16_mul(params->m_Mean_Variance_Estimator_Sigmoid_K, (sample - params->m_Mean_Variance_Estimator_Sigmoid_X0)));
if ((x < F16(-50.))) {
return params->m_Mean_Variance_Estimator_Sigmoid_L;
} else if ((x > F16(50.))) {
return F16(0.);
} else {
return (fix16_div(params->m_Mean_Variance_Estimator_Sigmoid_L, (F16(1.) + fix16_exp(x))));
}
}
static void voc_algorithm_mox_model_init(VocAlgorithmParams *params) {
voc_algorithm_mox_model_set_parameters(params, F16(1.), F16(0.));
}
static void voc_algorithm_mox_model_set_parameters(VocAlgorithmParams *params, fix16_t sraw_std, fix16_t sraw_mean) {
params->m_Mox_Model_Sraw_Std = sraw_std;
params->m_Mox_Model_Sraw_Mean = sraw_mean;
}
static fix16_t voc_algorithm_mox_model_process(VocAlgorithmParams *params, fix16_t sraw) {
return (fix16_mul((fix16_div((sraw - params->m_Mox_Model_Sraw_Mean),
(-(params->m_Mox_Model_Sraw_Std + F16(VOC_ALGORITHM_SRAW_STD_BONUS))))),
F16(VOC_ALGORITHM_VOC_INDEX_GAIN)));
}
static void voc_algorithm_sigmoid_scaled_init(VocAlgorithmParams *params) {
voc_algorithm_sigmoid_scaled_set_parameters(params, F16(0.));
}
static void voc_algorithm_sigmoid_scaled_set_parameters(VocAlgorithmParams *params, fix16_t offset) {
params->m_Sigmoid_Scaled_Offset = offset;
}
static fix16_t voc_algorithm_sigmoid_scaled_process(VocAlgorithmParams *params, fix16_t sample) {
fix16_t x;
fix16_t shift;
x = (fix16_mul(F16(VOC_ALGORITHM_SIGMOID_K), (sample - F16(VOC_ALGORITHM_SIGMOID_X0))));
if ((x < F16(-50.))) {
return F16(VOC_ALGORITHM_SIGMOID_L);
} else if ((x > F16(50.))) {
return F16(0.);
} else {
if ((sample >= F16(0.))) {
shift =
(fix16_div((F16(VOC_ALGORITHM_SIGMOID_L) - (fix16_mul(F16(5.), params->m_Sigmoid_Scaled_Offset))), F16(4.)));
return ((fix16_div((F16(VOC_ALGORITHM_SIGMOID_L) + shift), (F16(1.) + fix16_exp(x)))) - shift);
} else {
return (fix16_mul((fix16_div(params->m_Sigmoid_Scaled_Offset, F16(VOC_ALGORITHM_VOC_INDEX_OFFSET_DEFAULT))),
(fix16_div(F16(VOC_ALGORITHM_SIGMOID_L), (F16(1.) + fix16_exp(x))))));
}
}
}
static void voc_algorithm_adaptive_lowpass_init(VocAlgorithmParams *params) {
voc_algorithm_adaptive_lowpass_set_parameters(params);
}
static void voc_algorithm_adaptive_lowpass_set_parameters(VocAlgorithmParams *params) {
params->m_Adaptive_Lowpass_A1 =
F16((VOC_ALGORITHM_SAMPLING_INTERVAL / (VOC_ALGORITHM_LP_TAU_FAST + VOC_ALGORITHM_SAMPLING_INTERVAL)));
params->m_Adaptive_Lowpass_A2 =
F16((VOC_ALGORITHM_SAMPLING_INTERVAL / (VOC_ALGORITHM_LP_TAU_SLOW + VOC_ALGORITHM_SAMPLING_INTERVAL)));
params->m_Adaptive_Lowpass_Initialized = false;
}
static fix16_t voc_algorithm_adaptive_lowpass_process(VocAlgorithmParams *params, fix16_t sample) {
fix16_t abs_delta;
fix16_t f1;
fix16_t tau_a;
fix16_t a3;
if ((!params->m_Adaptive_Lowpass_Initialized)) {
params->m_Adaptive_Lowpass_X1 = sample;
params->m_Adaptive_Lowpass_X2 = sample;
params->m_Adaptive_Lowpass_X3 = sample;
params->m_Adaptive_Lowpass_Initialized = true;
}
params->m_Adaptive_Lowpass_X1 =
((fix16_mul((F16(1.) - params->m_Adaptive_Lowpass_A1), params->m_Adaptive_Lowpass_X1)) +
(fix16_mul(params->m_Adaptive_Lowpass_A1, sample)));
params->m_Adaptive_Lowpass_X2 =
((fix16_mul((F16(1.) - params->m_Adaptive_Lowpass_A2), params->m_Adaptive_Lowpass_X2)) +
(fix16_mul(params->m_Adaptive_Lowpass_A2, sample)));
abs_delta = (params->m_Adaptive_Lowpass_X1 - params->m_Adaptive_Lowpass_X2);
if ((abs_delta < F16(0.))) {
abs_delta = (-abs_delta);
}
f1 = fix16_exp((fix16_mul(F16(VOC_ALGORITHM_LP_ALPHA), abs_delta)));
tau_a =
((fix16_mul(F16((VOC_ALGORITHM_LP_TAU_SLOW - VOC_ALGORITHM_LP_TAU_FAST)), f1)) + F16(VOC_ALGORITHM_LP_TAU_FAST));
a3 = (fix16_div(F16(VOC_ALGORITHM_SAMPLING_INTERVAL), (F16(VOC_ALGORITHM_SAMPLING_INTERVAL) + tau_a)));
params->m_Adaptive_Lowpass_X3 =
((fix16_mul((F16(1.) - a3), params->m_Adaptive_Lowpass_X3)) + (fix16_mul(a3, sample)));
return params->m_Adaptive_Lowpass_X3;
}
} // namespace sgp40
} // namespace esphome
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