RESTORETOOLS focuses primarily on iterative methods that solve the least-squares problem:
$$ \min_x |Ax - b|_2 $$
To address ill-posedness, the package utilizes Hybrid Krylov Methods. Specifically, it employs the Golub-Kahan Bidiagonalization process to project the large-scale problem onto a Krylov subspace of dimension $k$:
$$ \min_y \in \mathbbR^k | B_k y - \beta_1 e_1 |_2 + \lambda | y |_2 $$
where $B_k$ is a lower bidiagonal matrix. This allows for sophisticated regularization parameter selection methods (such as the discrepancy principle or GCV) to be applied to the small projected problem rather than the original large system.
Key algorithms implemented include:
The installation process for restoretools.pkg typically involves downloading the package from Apple's support website or another authorized source and then running the installer. Once installed, the tools can be accessed through the Terminal app, using specific commands related to each tool.
It's essential to note that some of these tools require a certain level of technical expertise to use effectively and safely. Misuse of these tools can lead to data loss or system instability, so they should be used with caution.
restoretools apply --source /backups/app_20250418.tar.gz --target /var/www/app
Ant Commander Pro file manager.