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VectorAround [{x1,x2,},{δ1,δ2,}]

represents a vector of uncorrelated approximate numbers or quantities with values xi and uncertainties δi.

VectorAround [{x1,x2,},{{Δ11,Δ12,},{Δ12,Δ22,},}]

represents a vector of approximate numbers or quantities with values xi and covariance matrix Δ.

VectorAround [{x1,x2},{{δ1,δ2},ρ}]

represents a pair of approximate numbers or quantities with uncertainties δ1, δ2 and correlation factor ρ.

VectorAround [{x1,x2,},{{δ1,δ2,},{{1,R12,},{R12,1,},}}]

represents a vector of approximate numbers or quantities with uncertainties δi and correlation matrix R.

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VectorAround [{x1,x2,},{δ1,δ2,}]

represents a vector of uncorrelated approximate numbers or quantities with values xi and uncertainties δi.

VectorAround [{x1,x2,},{{Δ11,Δ12,},{Δ12,Δ22,},}]

represents a vector of approximate numbers or quantities with values xi and covariance matrix Δ.

VectorAround [{x1,x2},{{δ1,δ2},ρ}]

represents a pair of approximate numbers or quantities with uncertainties δ1, δ2 and correlation factor ρ.

VectorAround [{x1,x2,},{{δ1,δ2,},{{1,R12,},{R12,1,},}}]

represents a vector of approximate numbers or quantities with uncertainties δi and correlation matrix R.

Details

  • VectorAround can be used to represent results of vector measurements in which there is statistical or other uncertainty.
  • When VectorAround is used in computations, uncertainties are by default propagated using a first-order series approximation, taking account of correlations within each individual VectorAround object, but assuming no correlations between different VectorAround objects.
  • Around [VectorAround[{x1,x2,},]] gives a list of Around [xi,] in which correlations between different values in the vector have been ignored.
  • VectorAround []["prop"] can be used to extract the following properties:
  • "Vector" central vector v in VectorAround [v,]
    "Covariance" covariance matrix Δ
    "Correlation" correlation matrix R
    "Distribution" MultinormalDistribution []
  • For linear computations, VectorAround [v,Δ] behaves like a vector whose values are distributed according to the multinormal distribution MultinormalDistribution [v,Δ].
  • VectorAround [{x1,x2},{{δ1,δ2},ρ}] gives VectorAround [{x1,x2},Δ], with covariance matrix Δ={{δ12,ρ δ1 δ2},{ρ δ1 δ2,δ22}}.
  • For vectors v, δ and correlation matrix R, VectorAround [v,{δ,R}] gives VectorAround [v,Δ], with covariance matrix Δ of components Δij=Rij δi δj. The correlation matrix R is expected to have diagonal elements Rkk=1.

Examples

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Basic Examples  (4)

A pair of uncorrelated uncertain numbers:

Wolfram Language code: VectorAround[{1.8, 2.4}, {0.3, 0.4}]

A pair of correlated uncertain numbers, with correlation factor :

Wolfram Language code: VectorAround[{1.8, 2.4}, {{0.3, 0.4}, 0.5}]

Alternatively, specify the same correlation using a correlation matrix:

Wolfram Language code: VectorAround[{1.8, 2.4}, {{0.3, 0.4}, {{1, 0.5}, {0.5, 1}}}]

A pair of correlated quantities, with correlation given by a covariance matrix:

Wolfram Language code: VectorAround[{Quantity[1.8, "Seconds"], Quantity[2.4, "Meters"]}, {{Quantity[0.09, "Seconds"^2], Quantity[0.06, "Meters"*"Seconds"]}, {Quantity[0.06, "Meters"*"Seconds"], Quantity[0.16, "Meters"^2]}}]

MeanAround on a list of vectors returns a VectorAround object:

Wolfram Language code: RandomVariate[MultinormalDistribution[{2, 3}, {{1, 0.5}, {0.5, 2}}], 10]
Wolfram Language code: MeanAround[%]

Properties & Relations  (1)

Take a multinormal distribution for 2D vectors and simulate it:

Wolfram Language code: vdist = MultinormalDistribution[{5, -4}, {{0.3, -0.1}, {-0.1, 0.2}}];
Wolfram Language code: Dimensions[vectors = RandomVariate[vdist, 100]]

VectorAround [vectors] estimates the mean and covariance matrix of the distribution:

Wolfram Language code: VectorAround[vectors]

MeanAround [vectors] describes the mean of the distribution and the covariance matrix associated with that mean:

Wolfram Language code: MeanAround[vectors]
Wolfram Research (2019), VectorAround, Wolfram Language function, https://reference.wolfram.com/language/ref/VectorAround.html.

Text

Wolfram Research (2019), VectorAround, Wolfram Language function, https://reference.wolfram.com/language/ref/VectorAround.html.

CMS

Wolfram Language. 2019. "VectorAround." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/VectorAround.html.

APA

Wolfram Language. (2019). VectorAround. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/VectorAround.html

BibTeX

@misc{reference.wolfram_2026_vectoraround, author="Wolfram Research", title="{VectorAround}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/VectorAround.html}", note=[Accessed: 18-August-2026]}

BibLaTeX

@online{reference.wolfram_2026_vectoraround, organization={Wolfram Research}, title={VectorAround}, year={2019}, url={https://reference.wolfram.com/language/ref/VectorAround.html}, note=[Accessed: 18-August-2026]}

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