covariance

syntax

• cov(a, b)
• cov(a, b, partioning) 

definition

1. cov(a, b) results in a parameter with the covariance of attributes a and b.
2. cov(a, b, partioning) results in an attribute with the covariance of attributes a and b, grouped by the partioning attribute. The domain unit of the resulting attribute is the values unit of the partioning attribute.

The value type of the values unit of the resulting attribute should be configured with the value type float32 or float64.

applies to

Attributes a and b with value types:

conditions

1. Attributes a and b need to match with regard to their value type.
2. Attributes a, b and partition need to match with regard to their domain unit.

since version

5.15

1. parameter<float32> covNrInhabitantsTemp:
      expr = "cov(float32(City/NrInhabitants), City/avgDailyTemperature)"; 
      result = -156.25
2. attribute<float32> covNrInhabitantsTempRegion (RegionDomain): expr = 
      "cov("
          "  float32(City/NrInhabitants)"
          ", City/avgDailyTemperature"
          ", City/RegionNr"
      ")";