/* ----------------------------------------------------------------------
* Copyright (C) 2019-2020 ARM Limited. All rights reserved.
*
* $Date:         09. December 2019
* $Revision:     V1.0.0
*
* Project:       CMSIS DSP Library
* Title:         arm_bayes_example_f32.c
*
* Description:   Example code demonstrating how to use Bayes functions.
*
* Target Processor: Cortex-M/Cortex-A
*
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/**
 * @addtogroup groupExamples Examples
 * @{
 *
 * @defgroup BayesExample Bayes Example
 *
 * \par Description:
 * \par
 * Demonstrates the use of Bayesian classifier functions. It is complementing the tutorial
 * about classical ML with CMSIS-DSP and python scikit-learn:
 * https://developer.arm.com/solutions/machine-learning-on-arm/developer-material/how-to-guides/implement-classical-ml-with-arm-cmsis-dsp-libraries
 *
 * \example arm_bayes_example_f32.c
 *
 * @} */

#include <math.h>
#include <stdio.h>
#include "arm_math.h"

/* 
Those parameters can be generated with the python library scikit-learn.
*/
arm_gaussian_naive_bayes_instance_f32 S;

#define NB_OF_CLASSES 3
#define VECTOR_DIMENSION 2

const float32_t theta[NB_OF_CLASSES*VECTOR_DIMENSION] = {
  1.4539529436590528f, 0.8722776016801852f, 
  -1.5267934452462473f, 0.903204577814203f, 
  -0.15338006360932258f, -2.9997913665803964f
}; /**< Mean values for the Gaussians */

const float32_t sigma[NB_OF_CLASSES*VECTOR_DIMENSION] = {
  1.0063470889514925f, 0.9038018246524426f, 
  1.0224479953244736f, 0.7768764290432544f, 
  1.1217662403241206f, 1.2303890106020325f
}; /**< Variances for the Gaussians */

const float32_t classPriors[NB_OF_CLASSES] = {
  0.3333333333333333f, 0.3333333333333333f, 0.3333333333333333f
}; /**< Class prior probabilities */

int32_t main(void)
{
  /* Array of input data */
  float32_t in[2];

  /* Result of the classifier */
  float32_t result[NB_OF_CLASSES];
  float32_t temp[NB_OF_CLASSES];
  float32_t maxProba;
  uint32_t index;
  
  S.vectorDimension = VECTOR_DIMENSION; 
  S.numberOfClasses = NB_OF_CLASSES; 
  S.theta = theta;          
  S.sigma = sigma;         
  S.classPriors = classPriors;    
  S.epsilon=4.328939296523643e-09f; 

  in[0] = 1.5f;
  in[1] = 1.0f;

  index = arm_gaussian_naive_bayes_predict_f32(&S, in, result,temp);

  maxProba = result[index];

#if defined(SEMIHOSTING)
  printf("Class = %d\n", index);
  printf("Max proba = %f\n", (double)maxProba);
#endif

  in[0] = -1.5f;
  in[1] = 1.0f;

  index = arm_gaussian_naive_bayes_predict_f32(&S, in, result,temp);

  maxProba = result[index];

#if defined(SEMIHOSTING)
  printf("Class = %d\n", index);
  printf("Max proba = %f\n", (double)maxProba);
#endif

  in[0] = 0.0f;
  in[1] = -3.0f;

  index = arm_gaussian_naive_bayes_predict_f32(&S, in, result,temp);

  maxProba = result[index];

#if defined(SEMIHOSTING)
  printf("Class = %d\n", index);
  printf("Max proba = %f\n", (double)maxProba);
#endif

#if !defined(SEMIHOSTING)
  while (1); /* main function does not return */
#endif
}