comparison xtract/libxtract.h @ 146:baaa9d8b4d10

switched from single to double precision througout. closes #9

   *
   * Hopefully this not only makes the library more efficient when computing large numbers of features, but also makes it more flexible because extraction functions can be combined arbitrarily (one can take the irregularility of the Mel Frequency Cepstral Coefficients for example). 
   *
   * All feature extraction functions follow the same prototype:
   *
-int xtract_function_name(const float *data, const int N, const void *argv, float *result){
-  *
-  * \param const float *data points to an array of floats representing the input data
+int xtract_function_name(const double *data, const int N, const void *argv, double *result){
+  *
+  * \param const double *data points to an array of doubles representing the input data
   * \param const int N represents the number of elementes from *data to be considered in the calculation
   * \param const void *argv represents an arbitrary list of arguments. Used to pass in values required by the feature calculation
-  * \param float *result points to an array of floats, or a single float represnting the result of the calculation
+  * \param double *result points to an array of doubles, or a single double represnting the result of the calculation
   *
   *
   * It is up to the calling function to allocate enough memory for the *data, *argv, and *result, and to free it when required. Some feature extraction functions may also require an _init() function to be called in order to perform some initialisation. The struct xtract_function_descriptor_t is used to give an indication of recommended default values, and argc for the *argv array.
   *
   * LibXtract can be downloaded from http://www.sf.net/projects/libxtract

 
     int argc;
 
     struct {
 	xtract_type_t type; /* type of the array/value pointed to by argv */
-	float min[XTRACT_MAXARGS];
-	float max[XTRACT_MAXARGS];
-	float def[XTRACT_MAXARGS]; /* defaults */
+	double min[XTRACT_MAXARGS];
+	double max[XTRACT_MAXARGS];
+	double def[XTRACT_MAXARGS]; /* defaults */
 	xtract_unit_t unit[XTRACT_MAXARGS];
 	int donor[XTRACT_MAXARGS]; /* suggested donor functions for argv */
     } argv;
 
     xtract_bool_t is_scalar;

 
     /* The result.<> entries in descritors.c need to be checked */
     union {
 
 	struct {
-	    float min;
-	    float max;	   
+	    double min;
+	    double max;	   
 	    xtract_unit_t unit;
 	} scalar;
 
 	struct {
 	    xtract_vector_t format;

 #include <stdio.h>
 #define XTRACT
 #include "libxtract.h"
 
 main () {
-float values[] = {1.0, 2.0, 3.0, 4.0, 5.0};
+double values[] = {1.0, 2.0, 3.0, 4.0, 5.0};
 int N = 5;
-float mean;
+double mean;
 
 xtract[MEAN]((void *)values, N, NULL, &mean);
 
 printf("Mean = %.2f\n", mean);
 }
 \endverbatim
  * The calling function may additionally make some tests against the value returned by xtract
  * 
  */
 #ifdef XTRACT_H
-extern int(*xtract[XTRACT_FEATURES])(const float *data, const int N, const void *argv, float *result);
+extern int(*xtract[XTRACT_FEATURES])(const double *data, const int N, const void *argv, double *result);
 
 #endif
 
 /** \brief A structure to store a set of n_filters Mel filters */
 typedef struct xtract_mel_filter_ {
     int n_filters;
-    float **filters;
+    double **filters;
 } xtract_mel_filter;
 
 /** \brief A function to initialise a mel filter bank 
  * 
  * It is up to the caller to pass in a pointer to memory allocated for freq_bands arrays of length N. This function populates these arrays with magnitude coefficients representing the mel filterbank on a linear scale 
  */
-int xtract_init_mfcc(int N, float nyquist, int style, float freq_min, float freq_max, int freq_bands, float **fft_tables);
+int xtract_init_mfcc(int N, double nyquist, int style, double freq_min, double freq_max, int freq_bands, double **fft_tables);
 
 /** \brief A function to initialise bark filter bounds
  * 
  * A pointer to an array of BARK_BANDS ints most be passed in, and is populated with BARK_BANDS fft bin numbers representing the limits of each band 
  *
  * \param N: the audio block size
  * \param sr: The sample audio sample rate
  * \param *band_limits: a pointer to an array of BARK_BANDS ints
  */
-int xtract_init_bark(int N, float sr, int *band_limits);
+int xtract_init_bark(int N, double sr, int *band_limits);
 
 /** \brief An initialisation function for functions using FFT
  *
  * This function initialises global data structures used by functions requiring FFT functionality. It can be called multiple times with different feature names. Calling it more than once with the same feature name is not a valid operation and will result in a memory leak.
  *

  *
  * \param N: the size of the window
  * \param type: the type of the window as given in the enumeration window_types_
  *
  */
-float *xtract_init_window(const int N, const int type);
+double *xtract_init_window(const int N, const int type);
 
 /** \brief Free a window as allocated by xtract_make_window() 
  * 
- * \param *window: a pointer to an array of floats as allocated by xtract_make_window()
- *
- */
-void xtract_free_window(float *window);
+ * \param *window: a pointer to an array of doubles as allocated by xtract_make_window()
+ *
+ */
+void xtract_free_window(double *window);
 
 /* \brief A function to build an array of function descriptors */
 xtract_function_descriptor_t *xtract_make_descriptors();
 
 /* \brief A function to free an array of function descriptors */