zmctp 0.1.2

Bug fixes

• Fixed an incorrect mode formula in mode_ctp() and mode_zictp(). The previous implementation used a naive “round to nearest integer” rule that could return the wrong mode (e.g., returning 1 when the true mode was 0). Both functions now use the correct threshold-based rule.

• Fixed incorrect variance and skewness formulas in var_ctp() and skew_ctp(). The previous implementation used an incorrect algebraic combination of terms. var_zictp() and skew_zictp() required no changes and inherit the fix automatically, since they are built directly on var_ctp() and skew_ctp().

• Added an explicit validity check (gama > 0) to ctp.fit() and zictp.fit(). This closes a narrow edge case in the internal parameter reparameterization where sufficiently extreme starting conditions could otherwise allow an invalid (non-positive) gama during optimization. Typical fits to well-behaved data are unaffected.

Other changes

• tests/testthat/test-moments.R now contains a full suite of regression tests for mean_ctp(), var_ctp(), skew_ctp(), mode_ctp(), and their zero-modified counterparts, including a Monte Carlo cross-check of the skewness formula against simulated data from rzictp().

Note for existing users

If you used var_ctp(), skew_ctp(), var_zictp(), skew_zictp(), mode_ctp(), or mode_zictp() in version 0.1.1 or earlier, results from those functions will differ under 0.1.2 – the new results are correct. We recommend re-running any analysis that relied on their numeric output.

zmctp 0.1.1

• Added exported functions for theoretical moments and mode of the CTP and Zero-Modified CTP distributions: mean_ctp(), var_ctp(), skew_ctp(), mode_ctp(), mean_zictp(), var_zictp(), skew_zictp(), mode_zictp(). These were previously computed only internally within summary.ctpfit() and summary.zictpfit().

zmctp 0.1.0

• Initial CRAN release.