diff.md
In ivs: Interval Vectors

checks that `x` is a vector

Code
  iv_diff(x)
Condition
  Error in `iv_diff()`:
  ! `x` must be a vector, not an environment.

detects strictly increasing violations

Code
  iv_diff(x)
Condition
  Error in `iv_diff()`:
  ! `x` must be in strictly increasing order.
  i `x` is not in strictly increasing order at locations: `c(2, 4)`.

can detect strictly increasing violations in the presence of missings

Code
  iv_diff(x)
Condition
  Error in `iv_diff()`:
  ! `x` must be in strictly increasing order.
  i `x` is not in strictly increasing order at locations: `3`.

Code
  iv_diff(x)
Condition
  Error in `iv_diff()`:
  ! `x` must be in strictly increasing order.
  i `x` is not in strictly increasing order at locations: `c(5, 6)`.

Code
  iv_diff(x)
Condition
  Error in `iv_diff()`:
  ! `x` must be in strictly increasing order.
  i `x` is not in strictly increasing order at locations: `3`.