ARM - DSP Tutorial $1 - Example Class Marks Calculation

/**   
 * @defgroup ClassMarks Class Marks Example 
 *
 * \par Description:
 * \par
 * Demonstrates the use the Maximum, Minimum, Mean, Standard Deviation, Variance
 * and Matrix functions to calculate statistical values of marks obtained in a class.
 *
 * \note This example also demonstrates the usage of static initialization.
 * 
 * \par Variables Description:
 * \par
 * \li \c testMarks_f32 points to the marks scored by 20 students in 4 subjects
 * \li \c max_marks     Maximum of all marks
 * \li \c min_marks     Minimum of all marks
 * \li \c mean          Mean of all marks
 * \li \c var           Variance of the marks
 * \li \c std           Standard deviation of the marks
 * \li \c numStudents   Total number of students in the class
 *
 * \par CMSIS DSP Software Library Functions Used:
 * \par
 * - arm_mat_init_f32()
 * - arm_mat_mult_f32()
 * - arm_max_f32()
 * - arm_min_f32()
 * - arm_mean_f32()
 * - arm_std_f32()
 * - arm_var_f32()
 *
 * <b> Refer  </b>
 * \link arm_class_marks_example_f32.c \endlink
 *
 */


/** \example arm_class_marks_example_f32.c
  */ 
#include "arm_math.h"

#define USE_STATIC_INIT

 /* ----------------------------------------------------------------------
** Global defines 
** ------------------------------------------------------------------- */

#define TEST_LENGTH_SAMPLES (20*4)

/* ----------------------------------------------------------------------
** List of Marks scored by 20 students for 4 subjects
** ------------------------------------------------------------------- */ 
const float32_t testMarks_f32[TEST_LENGTH_SAMPLES] = 
{   
42.000000, 37.000000, 81.000000, 28.000000,
83.000000, 72.000000, 36.000000, 38.000000,
32.000000, 51.000000, 63.000000, 64.000000,
97.000000, 82.000000, 95.000000, 90.000000,
66.000000, 51.000000, 54.000000, 42.000000,
67.000000, 56.000000, 45.000000, 57.000000,
67.000000, 69.000000, 35.000000, 52.000000,
29.000000, 81.000000, 58.000000, 47.000000,
38.000000, 76.000000, 100.000000, 29.000000,
33.000000, 47.000000, 29.000000, 50.000000,
34.000000, 41.000000, 61.000000, 46.000000,
52.000000, 50.000000, 48.000000, 36.000000,
47.000000, 55.000000, 44.000000, 40.000000,
100.000000, 94.000000, 84.000000, 37.000000,
32.000000, 71.000000, 47.000000, 77.000000,
31.000000, 50.000000, 49.000000, 35.000000,
63.000000, 67.000000, 40.000000, 31.000000,
29.000000, 68.000000, 61.000000, 38.000000,
31.000000, 28.000000, 28.000000, 76.000000,
55.000000, 33.000000, 29.000000, 39.000000
}; 


/* ----------------------------------------------------------------------
* Number of subjects X 1 
* ------------------------------------------------------------------- */ 
const float32_t testUnity_f32[4] = 
{   
1.000,  1.000, 1.000,  1.000
};


/* ----------------------------------------------------------------------
** f32 Output buffer
** ------------------------------------------------------------------- */ 
static float32_t testOutput[TEST_LENGTH_SAMPLES];


/* ------------------------------------------------------------------
* Global defines 
*------------------------------------------------------------------- */
#define NUMSTUDENTS  20
#define     NUMSUBJECTS  4

/* ------------------------------------------------------------------
* Global variables 
*------------------------------------------------------------------- */

uint32_t  numStudents = 20;
uint32_t  numSubjects = 4; 
float32_t max_marks, min_marks, mean, std, var;
uint32_t student_num;   

/* ----------------------------------------------------------------------------------
* Main f32 test function.  It returns maximum marks secured and student number
* ------------------------------------------------------------------------------- */

int32_t main()
{

#ifndef  USE_STATIC_INIT

  arm_matrix_instance_f32 srcA;
  arm_matrix_instance_f32 srcB;
  arm_matrix_instance_f32 dstC; 

/* Input and output matrices initializations */ 
arm_mat_init_f32(&srcA, numStudents, numSubjects, (float32_t *)testMarks_f32); 
arm_mat_init_f32(&srcB, numSubjects, 1, (float32_t *)testUnity_f32); 
arm_mat_init_f32(&dstC, numStudents, 1, testOutput); 

#else

/* Static Initializations of Input and output matrix sizes and array */
arm_matrix_instance_f32 srcA = {NUMSTUDENTS, NUMSUBJECTS, (float32_t *)testMarks_f32};
arm_matrix_instance_f32 srcB = {NUMSUBJECTS, 1, (float32_t *)testUnity_f32};
arm_matrix_instance_f32 dstC = {NUMSTUDENTS, 1, testOutput};

#endif


/* ----------------------------------------------------------------------
*Call the Matrix multiplication process function 
* ------------------------------------------------------------------- */
arm_mat_mult_f32(&srcA, &srcB, &dstC);

/* ----------------------------------------------------------------------
** Call the Max function to calculate max marks among numStudents
** ------------------------------------------------------------------- */
arm_max_f32(testOutput, numStudents, &max_marks, &student_num); 

/* ----------------------------------------------------------------------
** Call the Min function to calculate min marks among numStudents
** ------------------------------------------------------------------- */
arm_min_f32(testOutput, numStudents, &min_marks, &student_num); 

/* ----------------------------------------------------------------------
** Call the Mean function to calculate mean
** ------------------------------------------------------------------- */
arm_mean_f32(testOutput, numStudents, &mean);

/* ----------------------------------------------------------------------
** Call the std function to calculate standard deviation
** ------------------------------------------------------------------- */
arm_std_f32(testOutput, numStudents, &std);

/* ----------------------------------------------------------------------
** Call the var function to calculate variance
** ------------------------------------------------------------------- */
arm_var_f32(testOutput, numStudents, &var);

    while(1);                             /* main function does not return */
}