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ElasticTTISG

sweep.equations.ElasticTTISG 

ElasticTTISG(spatial_order=8, device='cpu', backend='torch')

Bases: sweep.equations.elastic_tti.ElasticTTI

First-order 2-D three-component elastic TTI wave equation (axis-aligned SG).

Same physics as :class:ElasticTTI (Bond-rotated TTI stiffness, 8 raw model parameters) but with derivatives taken on an axis-aligned standard staggered grid (forward / backward FD pairs along x and z). Mixed-location stiffness couplings are used directly without interpolation — this is a clean no-interpolation SG reference companion to the RSG implementation. CPML follows the staggered-grid cpmls convention (8 profiles).

Models (constructor input order)

  • vp0 (m/s): VTI-frame vertical P velocity.
  • vs0 (m/s): VTI-frame vertical S velocity.
  • rho (kg/m^3): Density.
  • epsilon: Thomsen epsilon.
  • delta: Thomsen delta.
  • gamma: Thomsen gamma.
  • theta (rad): Tilt angle.
  • phi (rad): Azimuth angle.

Wavefields

  • vx (aliases: velocity_x): Particle velocity in x; default receiver.
  • vy (aliases: velocity_y): Particle velocity in y.
  • vz (aliases: velocity_z): Particle velocity in z; default receiver.
  • sxx (aliases: stress_xx): Normal stress xx; default source.
  • szz (aliases: stress_zz): Normal stress zz; default source.
  • syz (aliases: stress_yz): Shear stress yz.
  • sxz (aliases: stress_xz): Shear stress xz.
  • sxy (aliases: stress_xy): Shear stress xy.
  • m_vxx: CPML memory for dvx/dx (internal).
  • m_vxz: CPML memory for dvx/dz (internal).
  • m_vyx: CPML memory for dvy/dx (internal).
  • m_vyz: CPML memory for dvy/dz (internal).
  • m_vzx: CPML memory for dvz/dx (internal).
  • m_vzz: CPML memory for dvz/dz (internal).
  • m_txxx: CPML memory for dsxx/dx (internal).
  • m_txzz: CPML memory for dsxz/dz (internal).
  • m_txyx: CPML memory for dsxy/dx (internal).
  • m_tyzz: CPML memory for dsyz/dz (internal).
  • m_txzx: CPML memory for dsxz/dx (internal).
  • m_tzzz: CPML memory for dszz/dz (internal).

Defaults

  • source_type: ['sxx', 'szz']
  • receiver_type: ['vx', 'vz']
  • pml_type: 'cpmls'

Build the 2-D-3C elastic TTI equation operator (axis-aligned SG).

Parameters:

  • spatial_order –

    FD accuracy order of the staggered first-derivative operator — e.g. spatial_order=4 is fourth-order accurate. Internally the half-stencil width is M = spatial_order // 2 (used for loop bounds and PML padding). Must be an even integer (2, 4, 6, 8, 10, …). Performance note (impl='c' on CUDA): the compiled kernels ship template specialisations only for spatial_order ∈ {2, 4, 6, 8}. Above 8 the dispatcher drops to a generic runtime path (order = -1 in src/sweep/csrc/cuda/equations/elastic_tti_sg2d/forward.cu) which uses more registers and runs noticeably slower. The PyTorch eager path is unaffected. Defaults to 8.

  • device –

    Device for the operator's static gradient kernels. Use 'cuda' / a torch.device for GPU runs so the propagator can follow without a host↔device copy. Defaults to 'cpu'.

  • backend –

    Array / programming backend, 'torch' or 'jax'. When you later want impl='c', leave this on 'torch'. Defaults to 'torch'.

C_HAS_RECURSIVE_CKPT class-attribute 

C_HAS_RECURSIVE_CKPT = False

bool(x) -> bool

Returns True when the argument x is true, False otherwise. The builtins True and False are the only two instances of the class bool. The class bool is a subclass of the class int, and cannot be subclassed.

C_NAME class-attribute 

C_NAME = 'elastic_tti_sg2d'

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to sys.getdefaultencoding(). errors defaults to 'strict'.

prepare_models_for_c class-attribute 

prepare_models_for_c = True

bool(x) -> bool

Returns True when the argument x is true, False otherwise. The builtins True and False are the only two instances of the class bool. The class bool is a subclass of the class int, and cannot be subclassed.