# Verifies that the pair relationships are symmetric.

### Description

For certain analyses, the pairs links (which can be considered a type of
sparse matrix) need to be symmetric. For instance, if there is a row for
Subjects 201 and 202 with `R`

=0.5, there should be a second row for
Subjects 202 and 201 with `R`

=0.5.

This validation function is useful to some types of DF methods and some spatially-inspired methods.

### Usage

1 | ```
ValidatePairLinksAreSymmetric(linksPair)
``` |

### Arguments

`linksPair` |
The |

### Value

Returns `TRUE`

if symmetric. Throw an error with
`stop`

if asymmetric.

### Author(s)

Will Beasley

### See Also

`CreatePairLinksDoubleEntered`

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | ```
dsSingleLinks <- data.frame(
ExtendedID=c(1, 1, 1, 2),
SubjectTag_S1=c(101, 101, 102, 201),
SubjectTag_S2=c(102, 103, 103, 202),
R=c(.5, .25, .25, .5),
RelationshipPath=rep("Gen2Siblings", 4)
)
dsSingleOutcomes <- data.frame(
SubjectTag=c(101, 102, 103, 201, 202),
DV1=c(11, 12, 13, 41, 42),
DV2=c(21, 22, 23, 51, 52))
dsDouble <- CreatePairLinksDoubleEntered(
outcomeDataset=dsSingleOutcomes,
linksPairDataset=dsSingleLinks,
outcomeNames=c("DV1", "DV2"),
validateOutcomeDataset=TRUE)
dsDouble #Show the 8 rows in the double-entered pair links
summary(dsDouble) #Summarize the variables
ValidatePairLinksAreSymmetric(dsDouble) #Should return TRUE.
``` |