v2.30.0 (1 July 2022)

Complex:

• Added complex containers: complex_matrix, complex_vector, and complex_row_vector with basic arithmetic support. (#1133)
• Fixed indexing of a complex container to return the correct type. (#1158)
• Added many common linear algebra functions and container operations for complex types. (#1166)
• Fixed an issue reading in complex_matrix in the data block. (#1168)
• Added vectorized signatures for get_real and get_imag, e.g. get_real(complex_matrix) => matrix. (#1169)
• Added fft, inv_fft, fft2, and inv_fft2 to the language. (#1170)
• pow (and subsequently the ^ operator) now have overloads for complex containers. (#1186)
• to_complex is now vectorized. This means signatures like to_complex(matrix, matrix) => complex_matrix are now available. (#1208)
• Added signatures for addition, subtraction and division which mix scalars and complex vector types, broadcasting the scalar as appropriate. (#1212)
• Added svd_U, svd_V, singular_values, eigenvalues_sym, and eigenvectors_sym for complex inputs. (#1212)

New functions:

• Added L1 and L2 norms. (#1140)
• Added log_determinant_spd which is faster when the input matrix is known to be symmetric and positive definite. (#1178)
• Added wishart_cholesky_lpdf and wishart_cholesky_rng distribution functions. (#1188)
• Added multi_student_t_cholesky_lpdf and multi_student_t_cholesky_rng distribution functions. (#1197)
• Added inv_wishart_cholesky_lpdf and inv_wishart_cholesky_rng distribution functions. (#1202)
• Exposes inv_inc_beta. (#1211)

Misc:

• Re-enabled function inlining optimizations at O1. (#1097)
• Modified the optimizer to turn statements like 3 + 4i into to_complex(3,4) directly. (#1112)
• Added cumulative_sum(Vector/RowVector) for var<Matrix> types. (#1152)
• Improved compile times by accumulating all template requirements into a single require_all_t on user defined functions. (#1157)
• The --info and --debug-generate-data commands now use the Yojson library for it's output. (#1161, #1175)
• Bugfixed for output values in write_array that should be NaN. (#1165)
• --dump-stan-math-signatures now prints an entire signature on one line, no matter how long it is. (#1167)
• Fix --debug-generate-data for ordered vector data types. (#1173)
• Exposed an overload for cumulative_sum which takes and returns an array of integers. (#1174)
• The javascript interface (stancjs) now generates errors which look more like stanc3's by pointing out where in the supplied code the error occurred. (#1177)
• Cleaned up the internal structuring of modules in the compiler. (#1179)
• Cleaned up code for pretty printing the Middle Intermediate Representation (MIR). (#1180)
• Added --debug-mem-patterns flag, which will print out the memory type of variables (either Array of Structs or the more efficient Struct of Arrays pattern) when optimization is enabled. (#1185)
• Allowed the adding of new distributions without requiring them to support deprecated suffixes. (#1191)
• Added eigenvectors and eigenvalues functions which return the complex-valued eigenvectors or eigenvalues of a real (asymmetrix) matrix. (#1192)
• abs is now vectorized for container types. fabs is now deprecated, as all usages can be replaced with abs thanks to array promotion rules. (#1195)
• Made installing the developer tools for the Stanc repository an interactive script with error handling. (#1200)
• Internally clean up how variable declarations are represented. (#1203)
• Simplified internal representations in the compiler. (#1204)
• The pretty-printer now preserves multiple declarations in one line like int a, b; rather than splitting them into two declarations. (#1207)
• Declarations are now allowed in places they previously would not parse, such as the only statement in the body of an if statement. (#1207)
• ./, / .*, and * now have consistent behavior with scalar arguments. (#1209)