Divisions are printed using `pow`

Description

pystencils prints divisions like 1/x as pow(x, -1.0).

The floating point pow function is of course undesirable due to performance concerns.

It looks like pystencils intends to print powers with small integer exponent using multiplications and divisions. However, the types of powers are collated between the base and exponent.

Note that sympy converts divisions to powers automatically.

MWE

import pystencils as ps
from pystencils import CreateKernelConfig
from pystencils.astnodes import Block, KernelFunction, SympyAssignment
from sympy.abc import x, y

equ = SympyAssignment(y, 1/x)
typed_equ = ps.typing.transformations.add_types(equ, CreateKernelConfig())
print(typed_equ)

kernel = KernelFunction(
  Block([typed_equ]),
  ps.Target.CPU,
  ps.Backend.C,
  ps.cpu.cpujit.make_python_function,
  None,
)
code = ps.get_code_str(kernel)
print(code)

Actual output

y ← x**CastFunc(-1, double)
FUNC_PREFIX void kernel(double x)
{
   const double y = pow(x, -1.0);
}

Expected output

y ← x**CastFunc(-1, int)
FUNC_PREFIX void kernel(double x)
{
   const double y = 1.0 / x;
}