"Zhang, Hong" <[email protected]> writes: > Another confusion which is not related to this topic is the usage of the word > "DAE". > I disagree with the statement "In general, this (the general form) is a > differential algebraic equation (DAE)" on page 141 of the manual. > The word "DAE" has been abused in the comments of many TS functions > (including TSComputeIFunction), where it actually should mean "DAE or ODE". > PETSc uses the same interfaces for both DAE and ODE, but it is wrong to > consider ODE as a special case of DAE. > They are fundamentally different from each other and should be distinguished > explicitly in the manual and the source code.
Is this not valid usage? "Thus, ODEs have index 0." http://www.scholarpedia.org/article/Differential-algebraic_equations
