---

Utilities Interface.
[libgnn]

---

Detailed Description

This module contains miscelaneous utilities, like vector operations not available in the original GSL specification, access to an application-wide random number generator, etc.

Defines
#define	GNN_MIN(x, y)   ( ((x) < (y))? (x) : (y) )
	gets the minimum of two values.
#define	GNN_MAX(x, y)   ( ((x) > (y))? (x) : (y) )
	gets the maximum of two values.
#define	GNN_SIGN(x)   ( ((x) > 0)? 1 : -1 )
	gets the sign of a value.
#define	GNN_SHIFT2(a, b, c)   (a)=(b);(b)=(c);
	shifts two to the left.
#define	GNN_SHIFT3(a, b, c, d)   (a)=(b);(b)=(c);(c)=(d);
	shifts three to the left.
#define	GNN_USE_SIGN(a, b)   ( (b) >= 0.0 ? fabs(a) : -fabs(a) )
	use b's sign for a.
Functions
gsl_rng *	gnn_get_rng ()
	Get the global random number generator.
int	gnn_vector_resize (gsl_vector **vector, int new_size)
	Resize a vector.
int	gnn_vector_sum_elements (gsl_vector *v)
	Compute the sum of the vector's elements.
double	gnn_vector_euclidian_dist (const gsl_vector *v, const gsl_vector *u)
	Compute the euclidian distance between to vectors.
int	gnn_matrix_check_sizes_from_stream (FILE *stream, size_t *m, size_t *n)
	Compute matrix size from a stream.
gsl_vector *	gnn_vector_load (const char *filename)
	Load a vector from a file.
int	gnn_vector_save (const char *filename, gsl_vector *v)
	Saves a vector to a file.
gsl_matrix *	gnn_matrix_load (const char *filename)
	Load a matrix from a file.
int	gnn_matrix_save (const char *filename, gsl_matrix *A)
	Saves a matrix to a file.

---

Define Documentation

#define GNN_MAX (  x, y    )     ( ((x) > (y))? (x) : (y) )

Definition at line 50 of file gnn_utilities.h.

#define GNN_MIN (  x, y    )     ( ((x) < (y))? (x) : (y) )

Definition at line 44 of file gnn_utilities.h.

#define GNN_SHIFT2 (  a, b, c    )     (a)=(b);(b)=(c);

Definition at line 62 of file gnn_utilities.h.

#define GNN_SHIFT3 (  a, b, c, d    )     (a)=(b);(b)=(c);(c)=(d);

Definition at line 68 of file gnn_utilities.h.

#define GNN_SIGN (  x    )     ( ((x) > 0)? 1 : -1 )

Definition at line 56 of file gnn_utilities.h.

#define GNN_USE_SIGN (  a, b    )     ( (b) >= 0.0 ? fabs(a) : -fabs(a) )

Definition at line 74 of file gnn_utilities.h.

---

Function Documentation

gsl_rng* gnn_get_rng (    )

This function returns a pointer to an application-wide GSL random number generator. It allocates a new one if not defined yet. The type of the random number generator is given by the constant libgnn Global Definitions.. Note: This function is not thread safe. Returns: A pointer to the random number generator. Definition at line 69 of file gnn_utilities.c.

int gnn_matrix_check_sizes_from_stream (  FILE *    stream, size_t *    m, size_t *    n )

Todo: Make this function check for the integrity of the matrix. This function reads a stream until it reaches EOF, and makes an estimation of the contained matrix size. Parameters: stream  A file stream. m  A pointer to the variable to store the number of rows. n  A pointer to the variable to store the number of columns. Returns: Returns 0 if succeeded. Definition at line 201 of file gnn_utilities.c.

gsl_matrix* gnn_matrix_load (  const char *    filename )

This function loads a matrix from a file. It creates a gsl_matrix of the correct size. Parameters: filename  The file name from where the matrix should be loaded. Returns: A pointer to a new gsl_matrix. Definition at line 321 of file gnn_utilities.c.

int gnn_matrix_save (  const char *    filename, gsl_matrix *    A )

This function saves a matrix to a file. Parameters: filename  The file name from where the matrix should be loaded. A  A gsl_matrix which should be saved. Returns: Returns 0 if suceeded. Definition at line 369 of file gnn_utilities.c.

double gnn_vector_euclidian_dist (  const gsl_vector *    v, const gsl_vector *    u )

This function computes the euclidian distance between to vectors, given by: Parameters: v  A pointer to a vector of size . u  A pointer to a vector of size . Returns: Returns the distance. Definition at line 172 of file gnn_utilities.c.

gsl_vector* gnn_vector_load (  const char *    filename )

This function loads a vector from a file. It creates a gsl_vector of the correct size. Parameters: filename  The file name from where the vector should be loaded. Returns: A pointer to a new gsl_vector. Definition at line 248 of file gnn_utilities.c.

int gnn_vector_resize (  gsl_vector **    vector, int    new_size )

This function resizes a vector and tries to preserve all posible values, i.e. where is the vector before and is the vector after resizing, and . Parameters: vector  A vector. new_size  The new size ( in the explanation above). Returns: Returns 0 if succeeded. Definition at line 98 of file gnn_utilities.c.

int gnn_vector_save (  const char *    filename, gsl_vector *    v )

This function saves a vector to a file. Parameters: filename  The file name from where the vector should be loaded. A  A gsl_vector which should be saved. Returns: Returns 0 if suceeded. Definition at line 296 of file gnn_utilities.c.

int gnn_vector_sum_elements (  gsl_vector *    v )

This function computes the sum of the vector's elements, that is: Parameters: v  A pointer to a vector of size . Returns: Returns the sum of its elements. Definition at line 150 of file gnn_utilities.c.

---