sps 0.6.3

• Extra arguments to sps_iterator() now work correctly (#9).

sps 0.6.2

• Added divisor_method() to more easily generate divisor functions for prop_allocation() by name.

• prop_allocation() is now faster.

• Added sps_iterator() to make an iterator that draws a SPS one unit at a time.

sps 0.6.1

• Added a new vignette to show how inclusion probabilities are calculated.

• inclusion_prob() and sps() now use kit::topn() when available for partial sorting.

sps 0.6.0

• inclusion_prob() is now faster with a single stratum, improving the performance of sps() and expected_coverage().

• By default, sps_repweights() automatically picks the smallest tau to keep the replicate weights from being negative. Inspired by svrep::make_gen_boot_factors().

• Now requires R >= 4.1, which has been the case for a while (closing #2).

sps 0.5.4

• Added becomes_ta() to determine the sample size when a unit enter the take-all stratum.

• Internal changes to the way classes are instantiated. No user-visible changes.

• Updated maintainer email.

sps 0.5.3

• Documentation only; no changes to any functions.

sps 0.5.2

• Added a vignette.

• A single sample size is now recycled for each stratum when drawing samples or calculating inclusion probabilities.

• Added a cutoff argument that puts units with sizes above the cutoff into a take-all stratum.

• sps objects now inherit from numeric instead of integer.

• Replacement methods for length and levels no longer mangle sps objects.

sps 0.5.0

• prop_allocation() gets a new argument for breaking ties. The default now breaks ties according to the references; the old behavior can be had by setting ties = "first".

• Argument names for prop_allocation(), expected_coverage(), and sps_repweights() have changed to be either more descriptive, or consistent with the names for other functions.

• Fixed a bug when calculating inclusion probabilities that could result in ties not breaking according to position (as documented) when alpha > 0.

• Simplified the codebase.

sps 0.4.1

• Added a new argument alpha for calculating inclusion probabilities. It can be used to place units with inclusion probabilities close to 1 into the take-all stratum. This was implicitly 0 in previous versions, but the current default is 1e-4.

• All functions can now accept size vectors with zeros.

• sps() is now faster, especially for large populations.

• Added a function factory to generate other order sampling methods.

sps 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.

sps 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().

sps 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.

sps 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).