GD32F303之最小二乘法

static void leastSquareLinearFit(float32_t x[], float32_t y[], const int num, float32_t *a, float32_t *b)

{

        float32_t sum_x2 = 0.0;

        float32_t sum_y  = 0.0;

        float32_t sum_x  = 0.0;

        float32_t sum_xy = 0.0;

        

        {

                for (int i = 0; i < num; ++i) 

                {

                         sum_x2 += x[i]*x[i];

                         sum_y += y[i];

                         sum_x += x[i];

                         sum_xy += x[i]*y[i];

                 }

        }

        *a = (num*sum_xy - sum_x*sum_y)/(num*sum_x2 - sum_x*sum_x);

        *b = (sum_x2*sum_y - sum_x*sum_xy)/(num*sum_x2-sum_x*sum_x);

}

void lsm_test(void)

{

        float32_t a,b;

        static float32_t tempx[96] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1.46667, 11.4667,

                31.6, 52.7333, 80.3333, 116.333, 156.6, 199.4, 242.2, 283.4,

                329.2, 379.333, 431.333, 482.6, 541, 594.4, 643.533, 692.133,

                736.267, 772.667, 810.133, 841.867, 868.2, 892.4, 917.667, 

                939.8, 954.667, 969, 976.8, 983.4, 987.467, 994.933, 1023.67, 

                875.2, 873.933, 758.8, 678.2, 515.867, 782.533, 908.8, 779.2, 

                831.4, 645.533, 734.067, 679.533, 610.267, 565.067, 512.467, 

                462, 405.2, 354.133, 302, 247.8, 191.533, 140, 94.2667, 57.5333, 

                25.9333, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; // x

        

        static float32_t tempy[96] = {0.595, 0.595, 0.595, 0.595, 0.595, 0.595,

                0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 

                0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595,

                0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 0.595, 1.785, 2.57833, 3.927, 

                5.79233, 7.379, 9.48133, 11.1473, 12.4167, 13.6627, 16.193701, 18.248699, 

                19.042, 19.042, 19.105301, 16.6383, 17.240999, 14.631, 11.8217, 11.663, 

                12.155, 15.488, 21.859301, 19.32, 19.042, 19.6133, 21.105, 22.9937, 

                20.827299, 23.858299, 23.0333, 19.2883, 15.6937, 21.5893, 23.802999, 

                20.518299, 21.5893, 17.907301, 17.971001, 17.574301, 16.781, 15.5513, 

                12.3773, 10.2747, 8.60867, 6.86333, 5.39567, 3.88767, 2.856, 2.142, 

                2.142, 0.952, 0.952, 0.952, 0.952, 0.952, 0.952, 0.952, 0.952, 0.952, 0.952,

                0.952, 0.952, 0.952, 0.952 }; // y

        leastSquareLinearFit(tempx,tempy,96,&a,&b);

                printf("a=%f        b=%f",a,b);

}

/*

    昆明电器科学研究所 张恩寿 2019年5月3日

        

        

*/

#include "bitband.h"

#include "led_config.h"

#include "systick.h"

#include "usart.h"

#include "spi_flash.h"

#include "tft.h"

#include "key_lookup.h"

#include "lsm.h"









int main(void)

{                        

        systick_config(120);

        nvic_priority_group_set(NVIC_PRIGROUP_PRE2_SUB2);

        usart0_init(115200);

    led_init();

        lsm_test();

        

        while(1)

        {

                led_on();

                delay_nms(600);

                led_off();

                delay_nms(600);

        }

                

}