mbs_polynomial.c File Reference

#include "mbs_polynomial.h"
#include "mbs_1D_array.h"
#include "mbs_matrix.h"
#include "mbs_message.h"
#include "nrfct.h"
#include <math.h>
#include <stdlib.h>

Functions
int	factorial (int n)
int	mbs_polynomial_check (MbsPolynomial *poly)
	Check the validity of the provided polynomial. More...
MbsPolynomial *	mbs_polynomial_new (int order)
	Allocate a polynomial. More...
void *	mbs_polynomial_delete (MbsPolynomial *poly)
	Free a polynomial and return NULL. More...
MbsPolynomial *	mbs_polynomial_constrained (int nb_pos, double **pos_xy, int nb_deriv, double **deriv_xyp)
	Create a polynomial fulfilling the position and first derivative. More...
double	mbs_polynomial_get_value (MbsPolynomial *poly, double x, int deriv)
	Evaluate the polynomial without any checks. More...
int	mbs_polynomial_eval (MbsPolynomial *poly, double x, double *y, int deriv)
	Evaluate the polynomial (or its nth derivative) at the provided coordinate. More...
int	mbs_polynomial_print (MbsPolynomial *poly)
	Print information about the polynomial. More...
int	mbs_polynomial_eval_vec (MbsPolynomial *poly, int nx, double *vx, double **p_vy, int deriv)
	Evaluate the polynomial (or its nth derivative) at the provided coordinates vector. More...

Detailed Description

Implement polynomial-related function for MBsysC.

Creation date: 21-06-2023

Author

Robotran team

(c) Universite catholique de Louvain

Function Documentation

factorial()

int factorial

(

int

n

)

mbs_polynomial_check()

int mbs_polynomial_check

(

MbsPolynomial *

poly

)

Check the validity of the provided polynomial.

Parameters

[in]

poly

The adress of the polynomial structure.

Returns

Status, null if polynomial is valid, negative value otherwhise.

mbs_polynomial_constrained()

MbsPolynomial* mbs_polynomial_constrained	(	int	nb_pos,
		double **	pos_xy,
		int	nb_deriv,
		double **	deriv_xyp
	)

Create a polynomial fulfilling the position and first derivative.

The function is not optimized and may use a big amount of memory for heavily constrained polynomial. It uses a LU decomposition to solve the system.

Polynomial interpolation is not adapted when order is high due to the Runge's phenomenon.

The order of the polynomial is computed from the number of condition set.

Parameters

[in]	nb_pos	The number of position that the polynomial must pass by. Must be strictly positive.
[in]	pos_xy	The array containing the x and y coordinates of the function. The size is [nb_pos; 2]. Duplicated x-coordinates are forbidden.
[in]	nb_deriv	The number of specified polynomial derivative. Must be positive or null.
[in]	deriv_xyp	The array containing the x coordinates and the yp derivative of the function. The size is [nb_pos; 2]. Duplicated x-coordinates are forbidden. NULL can be provided if nb_deriv is null.

Returns

A polynomial that fulfills the position and derivative. NULL if no such polynomial exists.

mbs_polynomial_delete()

void* mbs_polynomial_delete

(

MbsPolynomial *

poly

)

Free a polynomial and return NULL.

Parameters

[in,out]

poly

The polynomial to be free.

Returns

NULL

mbs_polynomial_eval()

int mbs_polynomial_eval	(	MbsPolynomial *	poly,
		double	x,
		double *	y,
		int	deriv
	)

Evaluate the polynomial (or its nth derivative) at the provided coordinate.

Parameters

[in]	poly	The polynomial of the function.
[in]	x	The coordinate at which the the function must be computed.
[out]	y	The pointer to store the function value.
[in]	deriv	The order of the derivative to be computed. The function is 0, the first derivative is 1...

Returns

Status, null if correct, negative if any error.

mbs_polynomial_eval_vec()

int mbs_polynomial_eval_vec	(	MbsPolynomial *	poly,
		int	nx,
		double *	vx,
		double **	p_vy,
		int	deriv
	)

Evaluate the polynomial (or its nth derivative) at the provided coordinates vector.

Parameters

[in]	poly	The polynomial of the function.
[in]	nx	The number of coordinate to be evaluated.
[in]	vx	The array containing the coordinates at which the the function must be computed.
[in,out]	p_vy	The pointer to array where the output array pointer is located. if it contains a NULL adress, the output array is allocated.
[in]	deriv	The order of the derivative to be computed. The function is 0, the first derivative is 1...

Returns

Status, null if correct, negative if any error.

mbs_polynomial_get_value()

double mbs_polynomial_get_value	(	MbsPolynomial *	poly,
		double	x,
		int	deriv
	)

Evaluate the polynomial without any checks.

Parameters

[in]	poly	The polynomial of the function.
[in]	x	The coordinate at which the the function must be computed.
[in]	deriv	The order of the derivative to be computed. The function is 0, the first derivative is 1...

Returns

The value of the polynomial.

mbs_polynomial_new()

MbsPolynomial* mbs_polynomial_new

(

int

order

)

Allocate a polynomial.

If order is negative, pointer is set to NULL.

Parameters

[in]

order

The order of the polynomial. A negative value means that the coefficient array is not allocated.

Returns

The allocated polynomial, NULL in case of error.

mbs_polynomial_print()

int mbs_polynomial_print

(

MbsPolynomial *

poly

)

Print information about the polynomial.

Parameters

[in]

poly

The polynomial.

Returns

Status, null if polynomial is initialized, negative otherwhise.