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)