v9.40.0

ModelingToolkit v9.40.0

Diff since v9.39.1

Merged pull requests:

• fix: fix missing unwrap in build_explicit_observed_function (#3040) (@AayushSabharwal)
• feat: add adjoint for remake_buffer (#3042) (@AayushSabharwal)
• Respect D(x)-like guesses (#3050) (@hersle)

Closed issues:

• Precise execution order of multiple discrete affect (#2745)
• discrete event error for DAE system (#3043)
• solve fails with InitialFailure : overdetermined system (#3047)
• D(x)-like guesses are not respected during initialization (#3049)

v9.39.1

ModelingToolkit v9.39.1

Diff since v9.39.0

Merged pull requests:

• We cannot fold unitful constants (#3036) (@YingboMa)
• Fix test setup (#3038) (@ChrisRackauckas)
• Remove incidence matrix from system show (#3039) (@ChrisRackauckas)
• Tolerate empty equations and uneven matching (#3041) (@YingboMa)

Closed issues:

• Weird results trying to simulate an RC circuit with AC power source (#1152)
• Incidence matrix structural_simplify (#2178)
• Parameter identifiability example from docs fails (#2881)
• incorrect units in observed equations (#2988)

v9.39.0

ModelingToolkit v9.39.0

Diff since v9.38.0

Merged pull requests:

• Move labelledarrays to extension testing (#3031) (@ChrisRackauckas)
• Run initialization on ODEs with superset initial conditions (#3032) (@AayushSabharwal)
• Add unit aware diff2term (#3034) (@YingboMa)
• Throw an error if structural simplification is applied twice (take 2) (#3035) (@YingboMa)

Closed issues:

• Inconsistency for how to give intiial conditions to DAEs with higher order derivatives. (#2619)
• Variables introduced during simplification of 2nd order to first order dont have the correct units. (#2959)
• Array variable units (#3009)

v9.38.0

ModelingToolkit v9.38.0

Diff since v9.37.1

Merged pull requests:

• Throw an error if structural simplification is applied twice (#3027) (@ChrisRackauckas)

Closed issues:

• repeated application of structural_simplify leads to error (#3012)

v9.37.1

ModelingToolkit v9.37.1

Diff since v9.37.0

Merged pull requests:

• fix: fix missing MTKParameters handling in linearize (#3006) (@AayushSabharwal)
• Dispatch for symbolic array units (#3015) (@aml5600)
• fix: appropriate error msg for invalid @defaults (#3022) (@ven-k)
• Override defaults when setting initial conditions with mapped unknowns(sys) (#3028) (@hersle)
• Handle dummy derivatives and more in initialize_equations (#3030) (@ChrisRackauckas)

Closed issues:

• MTK & linearization -- MTKParameters access out of bounds (#2941)
• Initial conditions set by mapping unknowns(sys) do not override defaults (#3025)
• Cannot initialize system with D(x)-like initialization equations (#3029)

v9.37.0

ModelingToolkit v9.37.0

Diff since v9.36.0

Merged pull requests:

• feat: update to new remake_buffer signature (#3020) (@AayushSabharwal)
• Make has_time_domain and get_time_domain more generic (#3026) (@YingboMa)

Closed issues:

• Building ODEProblem From ODESystem Causes AutoDiff To Fail (#2856)
• remake is broken with Bool parameters (#2866)
• BifurcationProblem drops observed variables from ODESystem (#2889)
• connect can lead to wrong flow equations (#3008)
• Simple example of structural_simplify giving ExtraVariablesSystemException (#3021)

v9.36.0

ModelingToolkit v9.36.0

Diff since v9.35.1

Merged pull requests:

• CompatHelper: bump compat for DynamicQuantities to 1, (keep existing compat) (#2990) (@github-actions[bot])
• CompatHelper: bump compat for DynamicQuantities to 1 for package docs, (keep existing compat) (#2991) (@github-actions[bot])
• fix: improve resolution of dependent parameter defaults (#3005) (@AayushSabharwal)
• feat: save discrete variables in callback init (#3007) (@AayushSabharwal)

Closed issues:

• several broken discrete-time examples (#2359)
• Autodiff fails mysteriously with well-defined nested defaults (#2997)
• plotting errors with time-dependent parameters (#3004)

v9.35.1

ModelingToolkit v9.35.1

Diff since v9.35.0

Merged pull requests:

• Fix unit conversion for expressions (#2998) (@contradict)
• registered function unit fix (#3002) (@isaacsas)

v9.35.0

ModelingToolkit v9.35.0

Diff since v9.34.0

Merged pull requests:

• fix: fix substitute duplicating equations (#2992) (@AayushSabharwal)
• Fix typo in get_unit for ops (#2999) (@contradict)
• refactor: improve error messages for under- and over-determined systems (#3000) (@AayushSabharwal)
• Fix @mtkmodel independent variable generation (#3001) (@hersle)

v9.34.0

ModelingToolkit v9.34.0

Diff since v9.33.1

Merged pull requests:

• Add support for symbolic units by normalizing them to SI units (#2621) (@YingboMa)
• refactor: store discrete portion in BlockedArray for efficiency, better handle event variables (#2945) (@AayushSabharwal)
• Expose independent variable as a system property (#2962) (@hersle)
• Hotfix to avoid DataFrames.jl piracy (#2966) (@MasonProtter)
• AD: Add ChainRules extension for MTKParameters construction (#2977) (@DhairyaLGandhi)
• Fix parameter dependencies across model hierarchy (#2978) (@SebastianM-C)
• CompatHelper: add new compat entry for ChainRulesCore in [weakdeps] at version 1, (keep existing compat) (#2980) (@github-actions[bot])
• refactor: default to use_union = false for ODEProblems (#2983) (@AayushSabharwal)
• fix: discover parameters from parameter dependencies, fix substitute (#2984) (@AayushSabharwal)
• make LabelledArrays an extension (#2985) (@SebastianM-C)
• Update MTKLabelledArraysExt.jl (#2987) (@ChrisRackauckas)
• Fix depwarns from solve_for (#2993) (@SebastianM-C)

Closed issues:

• Support scaled SI units (#2616)
• Type piracy by DataFrames.jl causes error during SDE simplification (#2965)
• ODEProblem from ODESystem does not sub nested constants (#2969)
• Memory and Performance Problem (#2971)