mrdivide_helper.h File Reference

Provides MATLAB Coder helper functions for right matrix division. More...

#include "rtwtypes.h"
#include <stddef.h>
#include <stdlib.h>

Include dependency graph for mrdivide_helper.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions
void	mrdiv (const double A[4], const double B[4], double Y[4])
	Calculates the right matrix division for two 2x2 matrices (Y = A * inv(B)).
void	mrdiv_2 (const double B_data[], int B_size, double Y_data[], int Y_size[2])
	Performs element-wise division of a scalar by each element of a matrix.

Detailed Description

Provides MATLAB Coder helper functions for right matrix division.

Author

Francesco Abate, MSA (Originally generated by MATLAB Coder)

Version

24.2 (MATLAB Coder version)

Date

2025-05-05

This auto-generated helper file from MATLAB Coder provides C equivalents of MATLAB's right matrix divide operator (/). This operation is used to solve linear matrix equations of the form Y * B = A by calculating Y = A * inv(B).

These functions are used as low-level utilities within more complex control algorithms, such as the Kalman filter, for matrix calculations.

Definition in file mrdivide_helper.h.

Function Documentation

mrdiv()

void mrdiv	(	const double	A[4],
		const double	B[4],
		double	Y[4]
	)

Calculates the right matrix division for two 2x2 matrices (Y = A * inv(B)).

Solves the matrix equation Y * B = A where A, B, and the result Y are all 2x2 matrices.

Parameters

[in]	A	A 4-element array representing the numerator 2x2 matrix (row-major).
[in]	B	A 4-element array representing the denominator 2x2 matrix (row-major), which will be inverted during the calculation.
[out]	Y	A 4-element array where the resulting 2x2 matrix Y is stored.

Returns

None

Warning

This function does not check if matrix B is invertible. Providing a singular matrix for B may result in undefined behavior or NaNs in the output.

Definition at line 22 of file mrdivide_helper.c.

{
  double a21;
  double a22;
  double a22_tmp;
  int Y_tmp;
  int r1;
  int r2;
  if (fabs(B[1]) > fabs(B[0])) {
    r1 = 1;
    r2 = 0;
  } else {
    r1 = 0;
    r2 = 1;
  }
  a21 = B[r2] / B[r1];
  a22_tmp = B[r1 + 2];
  a22 = B[r2 + 2] - a21 * a22_tmp;
  Y_tmp = r1 << 1;
  Y[Y_tmp] = A[0] / B[r1];
  r2 <<= 1;
  Y[r2] = (A[2] - Y[Y_tmp] * a22_tmp) / a22;
  Y[Y_tmp] -= Y[r2] * a21;
  Y[Y_tmp + 1] = A[1] / B[r1];
  Y[r2 + 1] = (A[3] - Y[Y_tmp + 1] * a22_tmp) / a22;
  Y[Y_tmp + 1] -= Y[r2 + 1] * a21;
}

mrdiv_2()

void mrdiv_2	(	const double	B_data[],
		int	B_size,
		double	Y_data[],
		int	Y_size[2]
	)

Performs element-wise division of a scalar by each element of a matrix.

This is a specialized helper function that appears to handle a scalar division operation, likely 1 / B where B is a scalar represented as a 1x1 matrix. The output dimensions are explicitly handled.

Parameters

[in]	B_data	Array containing the scalar divisor (the denominator).
[in]	B_size	The size of B_data (expected to be 1).
[out]	Y_data	Array where the result of the division is stored.
[out]	Y_size	The dimensions of the output array Y_data.

Returns

None

Warning

The behavior is undefined if the scalar in B_data is zero.

Definition at line 59 of file mrdivide_helper.c.

{
  if (B_size == 0) {
    Y_size[0] = 1;
    Y_size[1] = 0;
  } else {
    Y_size[0] = 1;
    Y_size[1] = 1;
    Y_data[0] = 1.0 / B_data[0];
  }
}

Referenced by cdEvaluation().

Here is the caller graph for this function: