dmd prediction of initial condition
Nobody has claimed this yet.
- Dominant language
- C++
- Stars
- 236
- Forks
- 47
- PR merge metrics
- No merged PRs in 30d
Description
My DMD code seems to be working, but it seems to make a large error at the starting time. Shouldn't DMD be able to reproduce the initial condition exactly? Looking at
https://www.librom.net/features.html
I can see the last equation in the DMD section
$$
\mathbf{u}(t) = \mathbf{\Phi\Lambda}^{{t}/{\Delta t}}\mathbf{b}_0
$$
using $\mathbf{b}_0=\mathbf{\Phi}^\dagger\mathbf{u}_0$ we get
$$
\mathbf{u}(t) = \mathbf{\Phi\Lambda}^{{t}/{\Delta t}}\mathbf{\Phi}^\dagger\mathbf{u}_0
$$
At $t=0$ we have $\mathbf{\Lambda}^{{t}/{\Delta t}}=\mathbf{1}$ and hence,
$$
\mathbf{u}(0) = \mathbf{\Phi}\mathbf{\Phi}^\dagger\mathbf{u}_0
$$
Since $\mathbf{\Phi}\mathbf{\Phi}^\dagger=\mathbf{1}$ we get
$$
\mathbf{u}(0)=\mathbf{u}_0
$$
Hence, the initial condition is faithfully reproduced. Is my understanding correct?
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reviewing the DMD documentation and equations referenced in the issue, then locate the existing DMD implementation and reproduce the reported initial-condition error. Done would require a clearly defined resolution explaining whether the observed behavior is expected or identifying the implementation change needed.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- data
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 20/100