mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-10-17 12:18:23 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

gh-69639: Add mixed-mode rules for complex arithmetic (C-like) (GH-124829)

Browse source 
"Generally, mixed-mode arithmetic combining real and complex variables should
be performed directly, not by first coercing the real to complex, lest the sign
of zero be rendered uninformative; the same goes for combinations of pure
imaginary quantities with complex variables." (c) Kahan, W: Branch cuts for
complex elementary functions.

This patch implements mixed-mode arithmetic rules, combining real and
complex variables as specified by C standards since C99 (in particular,
there is no special version for the true division with real lhs
operand).  Most C compilers implementing C99+ Annex G have only these
special rules (without support for imaginary type, which is going to be
deprecated in C2y).
This commit is contained in:
Sergey B Kirpichev 2024-11-26 18:57:39 +03:00 • committed by GitHub
parent dcf629213b
commit 987311d42e
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
15 changed files with 449 additions and 98 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Python/bltinmodule.c
View file

@ -2829,7 +2829,6 @@ builtin_sum_impl(PyObject *module, PyObject *iterable, PyObject *start)
double value = PyLong_AsDouble(item);
if (value != -1.0 || !PyErr_Occurred()) {
re_sum = cs_add(re_sum, value);
im_sum.hi += 0.0;
Py_DECREF(item);
continue;
}
@ -2842,7 +2841,6 @@ builtin_sum_impl(PyObject *module, PyObject *iterable, PyObject *start)
if (PyFloat_Check(item)) {
double value = PyFloat_AS_DOUBLE(item);
re_sum = cs_add(re_sum, value);
im_sum.hi += 0.0;
_Py_DECREF_SPECIALIZED(item, _PyFloat_ExactDealloc);
continue;
}