Commandline

GT4Py installs the gtpyc command (introduced in GDP 1 — Standalone Compiler CLI). Implementation is ongoing.

Usage

List available backends

$ gtpyc list-backends

            computation    bindings        CLI-enabled
---------   -----------    --------        -------------
<backend>   <lang>         <lang>, <lang>  <Yes | No>
...

Lists the currently implemented backends with computation language and possible language bindings. The last column informs whether CLI support was implemented for the backend.

Generate stencils from a GTScript module

Assume the following file structure:

$ tree .
pwd
├── constants.py
└── stencils.gt.py

stencils.gt.py contains the GTScript code to be compiled to stencils. The contents might look something like the following example.

my_stencils.gt.py

# [GT] using-dsl: gtscript

from numpy import float64

from .constants import PI


@function
def square(inp_field):
   return inp_field * inp_field


@lazy_stencil
def stencil_a(inp_field: Field[float64], out_field: Field[float64]):
   with computation(PARALLEL), interval(...):
      out_field = square(inp_field)


@lazy_stencil
def stencil_b(inp_field: Field[float64], out_field: Field[float64]):
   from __externals__ import COMPILE_TIME_VALUE
   with computation(PARALLEL), interval(...):
      out_field = PI * inp_field + COMPILE_TIME_VALUE

Then

$ gtpyc gen my_stencils.gt.py --backend=gt:cpu_ifirst --output-path=./my-stencils-out

Will generate the C++ stencil code files using the “gt:cpu_ifirst” backend for each stencil in the global namespace of gstencils.gt.py (also ones imported from other modules) and output them inside my-stencils-out/. The code files for each stencil are put in a subfolder named after the stencil:

$ tree .my-stencils-out/
my-stencils-out
├── stencil_a/
│   ├── computation.cpp
│   └── computation.hpp
└── stencil_b/
    ├── computation.cpp
    └── computation.hpp

The line

# [GT] using-dsl: gtscript

in my_stencils.gt.py is equivalent to writing

from gt4py.cartesian.gtscript import *

in a python module. It makes all symbols from the gt4py.gtscript module available.