Add methods for piecewise exponential distributions

[mclements]

Devin,

As a start, here are some modest changes for piecewise exponential distributions.

Please shout out if anything is unclear.

Kindly, Mark.

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.72%. Comparing base (e218e24) to head (2523781).
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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #137      +/-   ##
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+ Coverage   92.51%   92.72%   +0.20%     
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  Files          64       64              
  Lines        5544     6252     +708     
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+ Hits         5129     5797     +668     
- Misses        415      455      +40     

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[Copilot]

Pull Request Overview

This PR adds support for piecewise exponential distributions by introducing new distribution methods and their corresponding Rcpp exports, along with minor utility functions to support these implementations.

• Added Rcpp-exported test functions (hesim_bound and member_of) in test-utils.cpp and RcppExports.cpp.
• Extended the Rcpp module in distributions.cpp to include new methods (pdf, cdf, quantile, hazard, cumhazard) for the piecewise_exponential class.
• Updated the distributions header to compute the cumulative rate parameters and define new methods for the piecewise exponential distribution.

Reviewed Changes

Copilot reviewed 6 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/test-utils.cpp	Added test functions for hesim_bound and member_of.
src/distributions.cpp	Registered new piecewise exponential methods via the Rcpp module.
src/RcppExports.cpp	Exposed new C_test_hesim_bound and C_test_member_of functions.
inst/include/hesim/utils.h	Added utility functions hesim_bound and member_of with new includes.
inst/include/hesim/stats/distributions.h	Updated piecewise_exponential with cumulative rate computations and added distribution methods.

Files not reviewed (3)

• R/RcppExports.R: Language not supported
• tests/testthat/test-cpp-distributions.R: Language not supported
• tests/testthat/test-cpp-utils.R: Language not supported

Comments suppressed due to low confidence (2)

inst/include/hesim/utils.h:304

• Consider passing 'range' as a const reference (i.e., const std::vector& range) to avoid unnecessary copying.

inline int hesim_bound(double x, std::vector<double> range) {

inst/include/hesim/utils.h:315

• Consider passing 'lookup' as a const reference (i.e., const V& lookup) to avoid unnecessary copying.

template<class T, class V>
  bool member_of(T x, V lookup) {

[dincerti]

Looks good! Just some minor comments on function names and the edge case.

[mclements]

Devin: I have also added some casts in a number of integer comparisons to address some long-standing warnings.