Stan 2.34 Release notes drfting

cmdstan.txt

 - Add option `adaptation save_metric=1` to save adapted metric in separate JSON file with elements "stepsize", "metric_type" and "inv_metric" (#1203, #1229)

 - New argument under `output save_cmdstan_config`. If set to `1`, creates `output_config.json` which contains the argument tree and extra information (equivalent to the CSV file header) (#1204)

 - Adds `psis_resample` and `calculate_lp` as options for Pathfinder (#1234)
 
 - Removed usages of boost::lexical_cast (#1205)

 - Resolved various compiler warnings (#1206)

 - Fixed a linking issue when building `stansummary` (#1209)

 - Fixed an issue where the default values of some arguments were not printed in sufficient precision (#1215)

 - Improved the error users see if they are missing the stan or stan_math submodules (#1217)

 - Improved the dependency detection in the build system (#1219)

 - Added a warning when more PSIS draws are requested than total number of draws from single-pathfinders (#1221)

 - Disallowed pathfinder when the model has no parameters. (#1221)

 - Fixed a typo in `make help-dev`. (#1225)

 - Fixed several edge cases and unexpected behaviors in the way output filenames were generated for multi-chain sampling and multi-path Pathfinder (#1228)

 - Added a `version.hpp` header (#1231)

math.txt

 - Updated Boost headers to v1.81 (#2955)
 
 - Added the Dirichlet-Multinomial distribution to the Stan Math library (dirichlet_multinomial_lpmf, dirichlet_multinomial_log, and dirichlet_multinomial_rng). (#2979)

 - `binomial_logit_glm_lpmf` distribution added (#2946)

 - Improved numerical stability of Bernoulli CDF functions (#2784)

 - Replaced the `std::vector`s  for read/write events in `matrix_cl` with `tbb::concurrent_vectors` (#2905)

 - Added framework for generic higher-order autodiff support through finite-differences. (#2929)

 - Minor cleanup of numerical stability, constants, compound functions in OpenCL kernels (#2934)

 - Fixes aliasing issue in adjoint acccumulation for OpenCL (#2943)

 - Improve numerical stability of `binomial_logit` distribution (#2945)

 - Automatically detect UCRT toolchain use on Windows (#2948)

 - Update multiple functions to delegate to the compound functions (`log1p_exp`, etc.) where possible (#2950)

 - Fixed the RPATH to the TBB library being passed twice on the command line (#2952)

 - Split `eigendecompose` mix tests to fix CI memory issues (#2953)

 - Fix distribution test failures with row-vector integer inputs to bernoulli CDF functions (#2954)

 - Simplified usage of ref-type deduction (#2958)

 - Added OpenCL support for the `binomial_logit_glm` distribution (#2960)

 - Fixed a build configuration issue where the optional tbbmalloc and tbbmalloc_proxy libraries were built unconditionally. (#2969)

 - Remove unused meta requires (#2976)

 - Bugfix for uninitialized `var_value<Matrix>` types and assignment when the rhs of the assignment is an expression (#2978)

 - Invert the input matrix in-place which reduces the memory requirement for this function. (#2981)

 - Fixes the rng function for the Inverse Wishart Cholesky distribution. (#2984)

 - Fixed a compilation issue with the `check_symmetric` function on complex-valued inputs under LLVM 17 (#2991)

 - Fixed missing include guard for OpenCL rev headers (#2996)

 - Add helpful context to the failure message for the ad testing framework (#2997)

stan.txt

 - Resolved an issue in Pathfinder's multithreading which lead to non-reproducible results (#3239)

 - Improved the human-readability of the output of the JSON writer class (#3227)

 - Resolved various compiler warnings (#3228, #3234)

 - Added hooks to adaptive sampler methods to write adapted metric to JSON file. (#3230, #3248)

 - Changed bfgs and lbfgs's error messaging behavior so that the message is not split between stderr and stdout but is entirely sent to stderr. (#3238)

 - Fixed a bug in the stan opencl assign tests (#3219)

 - Updated PSIS to not add back the max and return the unnormalized resample ratios for stability (#3243)

 - Fixed an issue where trying to compute the potential scale reduction factor on an empty set of draws would lead to a crash (#3246)

 - Added flags to the Pathfinder service functions for turning off resampling and the calculation of the lp for the approximate draws. (#3249)

stanc3.txt

 - Added the `binomial_logit_glm` distribution (#1367)

 - Added the `dirichlet_multinomial` distribution. (#1389)

 - Added the ability to unpack a tuple during an assignment. For example, the following is now valid:
	```stan
	parameters {
	matrix[N, M] A;
	}
	model {
	matrix[N, M] Q;
	matrix[M, M] R;
	(Q, R) = qr_thin(A); // qr_thin returns a tuple(matrix, matrix)
	}
	```
	(#1360)

 - Exposed vectorized signatures for the `atan2` function. (#1364)
 
 - The Stan compiler will now warn you when you reassign a variable to itself. (#1358)

 - Updated the OCaml-to-JS compiler used to create stanc.js (#1365, #1381)

 - Updated the compiler to use OCaml 4.14 and newer versions of its dependencies. (#1366)

 - Reverted a change to SoA initialization, as the Math library has implemented a better fix. (#1376)

 - Fixed an issue with clang compilers and constructing tuples. (#1382)

 - The compiler no longer recognizes language constructs removed in 2.33. (#1388)

 - The deprecated implicit conversion of reals to boolean conditions has been removed. (#1388)