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NDSolve::ntdvdae NDSolveValue::ntdvdae ParametricNDSolve::ntdvdae ParametricNDSolveValue::ntdvdae

NDSolve::ntdvdae NDSolveValue::ntdvdae ParametricNDSolve::ntdvdae ParametricNDSolveValue::ntdvdae

Details

  • This message is issued when the solver cannot find an explicit formula for derivatives.
  • Off[message] switches off the message; On[message] switches it on. For example: Off[NDSolve::ntdvdae].

Examples

Basic Examples  (2)

An error occurs due to the square root:

Wolfram Language code: NDSolve[{Sqrt[f'[x]] == -1, f[1] == 1}, f, {x, 1, 2}]

Squaring both sides of the equation involving the square root resolves the issue:

Wolfram Language code: NDSolve[{f'[x] == 1, f[1] == 1}, f, {x, 1, 2}]

This calculation fails because an explicit formula for cannot be found:

Wolfram Language code: NDSolve[{f'[x] == Cos[f'[x]], f[1] == 1}, f, {x, 1, 2}]

This example can be handled by solving numerically for the derivative and using that solution in the input to NDSolve:

Wolfram Language code: NDSolve[{f'[x] == (f'[x] /. FindRoot[f'[x] == Cos[f'[x]], {f'[x], 1, 2}]), f[1] == 1}, f, {x, 1, 2}]