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NDSolve::indexss NDSolveValue::indexss ParametricNDSolve::indexss ParametricNDSolveValue::indexss

NDSolve::indexss NDSolveValue::indexss ParametricNDSolve::indexss ParametricNDSolveValue::indexss

Details

  • The message is issued when the mass matrix associated with the differential algebraic system becomes singular at certain locations during time integration.
  • Off[message] switches off the message; On[message] switches it on. For example: Off[NDSolve::indexss].

Examples

Basic Examples  (1)

The mass matrix associated with certain differential algebraic systems is singular even after index reduction at certain places:

Wolfram Language code: NDSolve[{x'[t] + t y[t] == Sin[t], x[t] + t y[t] == Cos[t], x[0] == 1}, {x, y}, {t, 0, 1}]

The integration is successful if the singularity can be avoided:

Wolfram Language code: NDSolve[{x'[t] + t y[t] == Sin[t], x[t] + t y[t] == Cos[t], x[0.001] == 1}, {x, y}, {t, 0.001, 1}]