JudiJacobian

[seaninho94]

Is it possible to visualize the Jacobian operator in its matrix form? I can only see the data, which is a JudiVector but i cannot see the Jacobian or Forward operator.

Thank you!

[mloubout]

These operator are matrix free, i.e. they only have an action F*q, J*dm, .... The matrix itself is never created as it would be way to big and unmanageable. Why do you want these as dense matrices?

[seaninho94]

There is no way to see the numerical values of the Jacobian matrix? I know that usually is too big but i'm using a small model.

Thank you

[mloubout]

There are no numerical values in our operators. They are linear operators that have defined behavior for a matrix-vector product they do not hold any value. There is no mechanism to transform our operators into a dense matrix neither for two reasons:

• they rely on Devito that generates code at runtime for the wave-equation.
• the framework is based on abstract types rather than pure vectors (i.e judiVector) so you cannot just multiply it with the identity matrix.

But our operators are fully defined for LSQR or such so access to the values shouldn't be necessary,

[ziyiyin97]

If you @seaninho94 insist to look at the numerical values, you can do

J_{ij}=e_i^T J e_j

[seaninho94]

Thank you very much!