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# std (MathScript RT Module Function)

LabVIEW 2012 MathScript RT Module Help

Edition Date: June 2012

Part Number: 373123C-01

»View Product Info Download Help (Windows Only)

Owning Class: statistics

Requires: MathScript RT Module

y = std(x)

y = std(x, w)

y = std(x, w, d)

## Description

Returns the standard deviation of a vector or matrix. This function works column-wise for matrices by default.

Details

Examples

## Inputs

Name Description
x Specifies a vector or matrix.
w Specifies a weight. w is a vector.
d Specifies the dimension of x across which to calculate the standard deviation if x is a matrix. d is a scalar that accepts the following values.

 1 (default) Calculates the standard deviation by column. 2 Calculates the standard deviation by row.

## Outputs

Name Description
y Returns the standard deviation of x. y is a scalar or vector.

## Details

w can be in one of the following three states:
• If x is a vector, w is a vector of the same size as x. If x is a matrix, w is a vector of the same size as the dimension of x across which to calculate the standard deviation. All elements in w must be greater than 0. LabVIEW normalizes w so the sum of all the elements in w is equal to 1.
• w is a vector with only one element, 1. The input matrix has no weight. LabVIEW normalizes the output by the length of the input matrix.
• w is a vector with only one element, 0, or w is an empty matrix. The input matrix has no weight. LabVIEW normalizes the output by the length of the input matrix minus one.

The following table lists the support characteristics of this function.

 Supported in the LabVIEW Run-Time Engine Yes Supported on RT targets Yes Suitable for bounded execution times on RT Not characterized

## Examples

X = [1, 2, 3, 4, 5, 6; 2, 4, 6, 8, 10, 12]
Y = std(X)