/**
* Returns the Chessboard distance to another vector
* Definition: chessboard dist. = max(|x1 - x2|, |y1 - y2|, ...)
*
* @param Math_Vector $vector Math_Vector object
*
* @return float on success
* @throws InvalidArgumentException
*/
public function chessboardDistance(Math_Vector $vector)
{
if (!Math_VectorOp::isVector($vector)) {
throw new InvalidArgumentException("Wrong parameter type, expecting a Math_Vector object");
}
$n = $this->size();
if ($vector->size() != $n) {
throw new InvalidArgumentException("Vector has to be of the same size");
}
$sum = 0;
$cdist = array();
for ($i = 0; $i < $n; $i++) {
$cdist[] = abs($this->_tuple->getElement($i) - $vector->_tuple->getElement($i));
}
return max($cdist);
}
/**
* 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);
}
/**
* Returns the Chessboard distance to another vector
* Definition: chessboard dist. = max(|x1 - x2|, |y1 - y2|, ...)
*
* @access public
* @param object $vector Math_Vector object
* @return float on success, a PEAR_Error object on failure
*/
function chessboardDistance($vector)
{
$n = $this->size();
$sum = 0;
if (Math_VectorOp::isVector($vector)) {
if ($vector->size() == $n) {
$cdist = array();
for ($i = 0; $i < $n; $i++) {
$cdist[] = abs($this->tuple->getElement($i) - $vector->tuple->getElement($i));
}
return max($cdist);
} else {
return PEAR::raiseError("Vector has to be of the same size");
}
} else {
return PEAR::raiseError("Wrong parameter type, expecting a Math_Vector object");
}
}
/**
* Vector division
* v / w = <v1 / w1, v2 / w2, ..., vk / wk>
*
* @access public
* @param object Math_Vector (or subclass) $v1
* @param object Math_Vector (or subclass) $v2
* @return object Math_Vector (or subclass) on success, PEAR_Error otherwise
*
* @see isVector()
*/
function divide($v1, $v2)
{
if (Math_VectorOp::isVector($v1) && Math_VectorOp::isVector($v2)) {
$n = $v1->size();
if ($v2->size() != $n) {
return PEAR::raiseError("Vectors must of the same size");
}
for ($i = 0; $i < $n; $i++) {
$d = $v2->get($i);
if ($d == 0) {
return PEAR::raiseError("Division by zero: Element {$i} in V2 is zero");
}
$arr[$i] = $v1->get($i) / $d;
}
return new Math_Vector($arr);
} else {
return PEAR::raiseError("V1 and V2 must be Math_Vector objects");
}
}
function testFromVector()
{
$this->assertTrue(Math_VectorOp::isVector($this->z) && $this->z->isValid());
}
/**
* Vector division
* v / w = <v1 / w1, v2 / w2, ..., vk / wk>
*
* @param object Math_Vector (or subclass) $v1
* @param object Math_Vector (or subclass) $v2
* @return object Math_Vector (or subclass) on success
* @throws InvalidArgumentException
*
* @see isVector()
*/
public static function divide($v1, $v2)
{
if (Math_VectorOp::isVector($v1) && Math_VectorOp::isVector($v2)) {
$n = $v1->size();
if ($v2->size() != $n) {
throw new InvalidArgumentException("Vectors must of the same size");
}
for ($i = 0; $i < $n; $i++) {
$d = $v2->get($i);
if ($d == 0) {
throw new Math_Vector_Exception("Division by zero: Element {$i} in V2 is zero");
}
$arr[$i] = $v1->get($i) / $d;
}
return new Math_Vector($arr);
} else {
throw new InvalidArgumentException("V1 and V2 must be Math_Vector objects");
}
}
