function Vector::std in Recommender API 7.6

Same name and namespace in other branches

1. 6.2 Matrix.php \Vector::std()

1 call to Vector::std()

Vector::correlation in classes/Matrix.php

Compute correlation with $vector. No caching option. Works for RealVector. SparseVector needs additional handling.

File

classes/Matrix.php, line 231

Class

Vector

This is the Vector superclass. @author danithaca

Code

function std($may_cache = FALSE) {
  if (!$may_cache || $this->std === NULL) {

    // force calculation
    $variance = $this
      ->variance($may_cache);
    $this->std = is_nan($variance) ? NAN : sqrt($variance);
  }
  return $this->std;
}