Changes in version 0.3.0

This version has a number of non-backwards compatible changes to address undesirable behavior with some functions.

• Largest-remainder rounding could result in prop_allocation() giving visibly non-proportional allocations, so it has been removed. The default is now the Jefferson/D’Hondt method.

• The method argument in prop_allocation() has been replaced with the divisor argument to supply a divisor function for rounding.

• The initial argument in prop_allocation() is recycled to ensure the initial allocation is feasible when supplying a single value. This change is not strictly backwards compatible as values that could not be ordinarily recycled no longer give an error.

• Supplying a vector of permanent random numbers to sps() or ps() that are generated with a given seed now gives the same result when setting that seed prior to calling sps() or ps(). This means that setting the seed to a given value can give a different sample compared to older versions, although permanent random numbers should be used for reproducible samples.

• The argument name for specifying strata is now strata instead of s in all functions. Partial matching means this change won’t break existing code.

Changes in version 0.2.0

• prop_allocation() gains two new arguments:

  1. initial sets the initial allocation for each stratum. This saves from having to manually keep track of an initial allocation and adjust the sample size passed to prop_allocation().

  2. method selects the apportionment method used to round a proportional allocation to integer values. In particular, highest-averages methods can be used in place of the largest-remainder method.

  The defaults for these arguments do not change the behavior of the function from previous versions.

• A few convenience functions have been added:

  1. ps() for drawing ordinary Poisson samples with the same interface as sps().

  2. inclusion_prob() for generating inclusion probabilities for a frame.

  3. expected_coverage() for calculating the expected number of strata when sampling from a frame.

• Some of the internals have been updated to improve performance with large frames.

• Most functions do a little more argument checking. In particular, it is no longer possible to pass length 0 arguments to sps(), prop_allocation(), or sps_repweights().

Changes in version 0.1.3

• Added the option to draw samples with permanent random numbers.

• Added methods for Math, Ops, [<-, and [[<- that strip attributes from sps objects so as not to treat the result as a sample.

Changes in version 0.1.2

• sps() now returns an integer vector (when possible), rather than a double.

• printing the matrix of replicate weights now shows row names (if any).