# Summarize a distance matrix

### Description

Given a distance matrix, return information above it, including
dimension, sparsity information, unmatchable members, summary of
finite distances, and, in the case of
`BlockedInfinitySparseMatrix`

, block structure.

### Usage

1 2 3 4 5 6 7 8 9 | ```
## S3 method for class 'InfinitySparseMatrix'
summary(object, ..., distanceSummary = TRUE)
## S3 method for class 'BlockedInfinitySparseMatrix'
summary(object, ...,
distanceSummary = TRUE, printAllBlocks = FALSE, blockStructure = TRUE)
## S3 method for class 'DenseMatrix'
summary(object, ..., distanceSummary = TRUE)
``` |

### Arguments

`object` |
A |

`...` |
Ignored. |

`distanceSummary` |
Default |

`printAllBlocks` |
If |

`blockStructure` |
If |

### Details

The output consists of several pieces.

Membership: Indicates the dimension of the distance.

Total (in)eligible potential matches: A measure of the sparsity of the distance. Eligible matches have a finite distance between treatment and control members; they could be matched. Ineligible matches have

`Inf`

distance and can not be matched. A higher number of ineligible matches can speed up matching, but runs the risk of less optimal overall matching results.Unmatchable treatment/control members: If any observations have no eligible matches (e.g. their distance to every potential match is

`Inf`

) they are listed here. See Value below for details of how to access lists of matchable and unmatchable treatment and control members.Summary of minimum matchable distance per treatment member: To assist with choosing a caliper, this is a numeric summary of the smallest distance per matchable treatment member. If you provide a caliper that is less than the maximum value, at least one treatment member will become unmatchable.

Block structure: For

`BlockedInfinitySparseMatrix`

, a quick summary of the structure of each individual block. (The above will all be across all blocks.) This may indicate which blocks, if any, are problematic.

### Value

A named `list`

. The summary for an
`InfinitySparseMatrix`

or `DenseMatrix`

contains the
following:

`total`

: Contains the total number of treatment and control members, as well as eligible and ineligible matches.`matchable`

: The names of all treatment and control members with at least one eligible match.`unmatchable`

: The names of all treatment and control members with no eligible matches.`distances`

: The summary of minimum matchable distances, if`distanceSummary`

is`TRUE`

.

For `BlockedInfinitySparseMatrix`

, the named `list`

instead of contains one entry per block, named after each block
(i.e. the value of the blocking variable) as well as a block
named 'overall' which contains the summary ignoring blocks. Each
of these entries contains a `list`

with entries 'total',
'matchable', 'unmatchable' and 'distances', as described above.