/**
* Solves a system of linear equations: Ax = b
*
* A system such as:
* <pre>
* a11*x1 + a12*x2 + ... + a1n*xn = b1
* a21*x1 + a22*x2 + ... + a2n*xn = b2
* ...
* ak1*x1 + ak2*x2 + ... + akn*xn = bk
* </pre>
* can be rewritten as:
* <pre>
* Ax = b
* </pre>
* where:
* - A is matrix of coefficients (aij, i=1..k, j=1..n),
* - b a vector of values (bi, i=1..k),
* - x the vector of unkowns (xi, i=1..n)
* Using: x = (Ainv)*b
* where:
* - Ainv is the inverse of A
*
* @static
* @access public
* @param object Math_Matrix $a the matrix of coefficients
* @param object Math_Vector $b the vector of values
* @return mixed a Math_Vector object on succcess, PEAR_Error otherwise
* @see vectorMultiply()
*/
function solve($a, $b)
{
// check that the vector classes are defined
if (!Math_Matrix::isMatrix($a) && !Math_VectorOp::isVector($b)) {
return PEAR::raiseError('Incorrect parameters, expecting a Math_Matrix and a Math_Vector');
}
$e = $a->invert();
if (PEAR::isError($e)) {
return $e;
}
return $a->vectorMultiply($b);
}
function testIsMatrix()
{
$this->assertTrue(Math_Matrix::isMatrix($this->m));
}
