`auto_contractor.auto_fac_funcs` — Modular Arithmetic Helpers¶

Source: qlat/auto_contractor/auto_fac_funcs.py

Note: Update this document when updating the source file.

Outline¶

Overview
Exported Functions
Function List
Examples

Overview¶

auto_fac_funcs is a thin re-export module that makes the modular arithmetic helper functions from qlat_utils available under the auto_contractor namespace. These functions are referenced by name in compiled expression code (through auto_fac_funcs_list) and resolved at evaluation time.

Exported Functions¶

All three functions are imported directly from qlat_utils:

Function	Description
`rel_mod(x, size)`	Compute `x mod size` (non-negative remainder)
`rel_mod_sym(x, size)`	Compute `x mod size` centred around zero (symmetric modulo)
`c_rel_mod_sqr(x, size)`	Squared modulus of the relative modular distance

Function List¶

The module exposes auto_fac_funcs_list, a plain list of the function names above. The compiled expression generator (compile.cexpr_code_gen_py) uses this list to recognise which position variables should be resolved to these helper functions rather than looked up from positions_dict.

auto_fac_funcs_list = [
    "rel_mod",
    "rel_mod_sym",
    "c_rel_mod_sqr",
]

Examples¶

import qlat as q
import auto_contractor as ac

q.begin_with_mpi([[1, 1, 1, 4]])

from auto_contractor.auto_fac_funcs import rel_mod, rel_mod_sym, c_rel_mod_sqr

print(rel_mod(7, 4))        # 3
print(rel_mod_sym(7, 4))    # -1
print(c_rel_mod_sqr(7, 4))  # 9.0

q.end_with_mpi()