# Lapack::leastSquaresByFactorisation

(PECL lapack >= 0.1.0)

Lapack::leastSquaresByFactorisationCalculate the linear least squares solution of a matrix using QR factorisation

### Description

public static Lapack::leastSquaresByFactorisation ( array `\$a` , array `\$b` ) : array

Solve the linear least squares problem, find min x in || B - Ax || Returns an array representing x. Expects arrays of arrays, and will return an array of arrays in the dimension B num cols x A num cols. Uses QR or LQ factorisation on matrix A.

`a`

Matrix A

`b`

Matrix B

### Return Values

Array of the solution matrix

### Examples

Example #1 Using Lapack::leastSquaresByFactorisation():

``` <?php \$a = array(     array( 1.44,  -7.84,  -4.39,   4.53),     array(-9.96,  -0.28,  -3.24,   3.83),     array(-7.55,   3.24,   6.27,  -6.64),     array( 8.34,   8.09,   5.28,   2.06),     array( 7.08,   2.52,   0.74,  -2.47),     array(-5.45,  -5.70,  -1.19,   4.70), ); \$b = array(     array( 8.58,   9.35),     array( 8.26,  -4.43),     array( 8.48,  -0.70),     array(-5.28,  -0.26),     array( 5.72,  -7.36),     array( 8.93,  -2.52),            ); \$result = Lapack::leastSquaresByFactorisation(\$a, \$b); ?> ```