How are weights computed in R matchit() function for full matching? In the example I have, a small number of treated subjects are matched to a large number of untreated controls.
I used
match= matchit(treat ~ SEX + ageint + bAVAL1 + bAVAL2, method = "full", caliper=0.3,
               exact  = c("SEX", "ageint"), data = data)

It makes sense that the treated subjects have weight=1. Why do the multiple control subjects matched to each treated subject have weights>1?
     weights          subclass
1    1.0000000        1
2    2.0421053        1
3    2.0421053        1
4    2.0421053        1
5    2.0421053        1
6    2.0421053        1
7    1.0000000        2
8    2.5526316        2
9    2.5526316        2
10   2.5526316        2
11   2.5526316        2
12   1.0000000        3
13   2.5526316        3
14   2.5526316        3
15   2.5526316        3
16   2.5526316        3


This is explained in the documentation for matchit().

[E]ach unit is assigned to a subclass, which represents the pair they
are a part of (in the case of k:1 matching) or the stratum they belong
to (in the case of exact matching, coarsened exact matching, full
matching, or subclassification). The formula for computing the weights
depends on the argument supplied to estimand. A new stratum
"propensity score" (p) is computed as the proportion of units in
each stratum that are in the treated group, and all units in that
stratum are assigned that propensity score. Weights are then computed
using the standard formulas for inverse probability weights: for the
ATT, weights are 1 for the treated units and p/(1-p) for the control
units; for the ATC, weights are (1-p)/p for the treated units and 1
for the control units; for the ATE, weights are 1/p for the treated
units and 1/(1-p) for the control units.
...
In each treatment group, weights are divided by the mean of the
nonzero weights in that treatment group to make the weights sum to the
number of units in that treatment group.

