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update docs
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ChrisZYJ committed Nov 19, 2024
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Expand Up @@ -125,7 +125,7 @@ For example, $m=n=p=499$ discretizes the domain into $500^3$ cells.
When the simulation is 2D/axi-symmetric or 1D, it requires that $p=0$ or $p=n=0$, respectively.

- `stretch_[x,y,z]` activates grid stretching in the $[x,y,z]$ directions.
The grid is gradually stretched such that the domain boundaries are pushed away from the origin along a specified axis. WENO7 does not support grid stretching.
The grid is gradually stretched such that the domain boundaries are pushed away from the origin along a specified axis.

- `a_[x,y,z]`, `[x,y,z]_a`, and `[x,y,z]_b` are parameters that define the grid stretching function. When grid stretching along the $x$ axis is considered, the stretching function is given as:

Expand Down Expand Up @@ -409,7 +409,7 @@ Note that `time_stepper = 3` specifies the total variation diminishing (TVD), th

- `adap_dt` activates the Strang operator splitting scheme which splits flux and source terms in time marching, and an adaptive time stepping strategy is implemented for the source term. It requires ``bubbles = 'T'``, ``polytropic = 'T'``, ``adv_n = 'T'`` and `time_stepper = 3`.

- `weno_order` specifies the order of WENO scheme that is used for spatial reconstruction of variables by an integer of 1, 3, 5, and 7, that correspond to the 1st, 3rd, 5th, and 7th order, respectively. WENO7 does not support grid stretching.
- `weno_order` specifies the order of WENO scheme that is used for spatial reconstruction of variables by an integer of 1, 3, 5, and 7, that correspond to the 1st, 3rd, 5th, and 7th order, respectively.

- `weno_eps` specifies the lower bound of the WENO nonlinear weights.
It is recommended to set `weno_eps` to $10^{-6}$ for WENO-JS, and to $10^{-40}$ for other WENO variants.
Expand All @@ -420,7 +420,7 @@ It is recommended to set `weno_eps` to $10^{-6}$ for WENO-JS, and to $10^{-40}$

- `wenoz_q` specifies the power parameter `q` used in the WENO-Z scheme. It controls how aggressively the smoothness coefficients scale the weights. A higher value of `wenoz_q` increases the sensitivity to smoothness, improving stability but worsening numerical dissipation. For WENO3 and WENO5, `q=1` is fixed, so `wenoz_q` must not be set. For WENO7, `wenoz_q` can be set to 2, 3, or 4.

- `teno` activates the TENO scheme in place of the default WENO-JS scheme ([Fu et al., 2016](references.md#Fu16)). TENO is a variant of the ENO scheme that is the least dissipative, but could be less robust for extreme cases. It uses a threshold to identify smooth and non-smooth stencils, and applies optimal weights to the smooth stencils. Only available for `weno_order = 5` and `7`. Requires `teno_CT` to be set.
- `teno` activates the TENO scheme in place of the default WENO-JS scheme ([Fu et al., 2016](references.md#Fu16)). TENO is a variant of the ENO scheme that is the least dissipative, but could be less robust for extreme cases. It uses a threshold to identify smooth and non-smooth stencils, and applies optimal weights to the smooth stencils. Only available for `weno_order = 5` and `7`. Requires `teno_CT` to be set. Does not support grid stretching.

- `teno_CT` specifies the threshold for the TENO scheme. This dimensionless constant, also known as $C_T$, sets a threshold to identify smooth and non-smooth stencils. Larger values make the scheme more robust but also more dissipative. A recommended value for teno_CT is `1e-6`. When adjusting this parameter, it is recommended to try values like `1e-5` or `1e-7` for TENO5. A smaller value can be used for TENO7.

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