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...heaply (without allocation), callers are encouraged to use PY_VECTORCALL_ARGUMENTS_OFFSET. Doing so will allow callables such as bound methods to make their onward calls cheaply. The bytecode interpreter already allocates space on the stack for the callable, so it can use this trick at no additional cost. See [3] for an example of how PY_VECTORCALL_ARGUMENTS_OFFSET is used by a callee to avoid allocation. For getting the actual number of arguments from the parameter n, the macro PyVectorcall_NAR...
...heapq module: >>> lst = [YourMin, MyMin, MyMin, YourMin, MyMax, YourMin, MyMax, YourMax, MyMax] >>> heapq.heapify(lst) #not needed, but it can't hurt >>> while lst: print heapq.heappop(lst), ... YourMin MyMin YourMin YourMin MyMin MyMax MyMax YourMax MyMax Furthermore, the findmin_Max code and both versions of Dijkstra could result in incorrect output by passing in secondary versions of Max. It has been pointed out [9] that the reference implementation given belo...
...heapq - implements the heap queue algoritm known from 1st year algorithms classes. Code by Kevin O'Connor, write-up by François Pinard, many improvements by Tim Peters. imaplib - added SSL support. imp - exposed the "import lock". (New in 2.3a2.) itertools - high speed, memory efficient looping constructs inspired by Haskell and SML. (New in 2.3a2.) (Some improvements in 2.3b1, including subsumption of times() into repeat(), and addition of chain() and cycle().) logging - a fle...
...heap as well. Using PyEval_Locals() will be much more efficient than PyEval_GetLocals(). This code: locals = PyEval_GetLocals(); if (locals == NULL) { goto error_handler; } Py_INCREF(locals); should be replaced with: locals = PyEval_Locals(); if (locals == NULL) { goto error_handler; } PyFrame_FastToLocals, etc. These functions were designed to convert the internal "fast" representation of the locals variables of a function to a dictionary, and vice versa. Calls to them are no long...
...heap-based stack frames [118], [119]. Platform Support Unladen Swallow is inherently limited by the platform support provided by LLVM, especially LLVM's JIT compilation system [7]. LLVM's JIT has the best support on x86 and x86-64 systems, and these are the platforms where Unladen Swallow has received the most testing. We are confident in LLVM/Unladen Swallow's support for x86 and x86-64 hardware. PPC and ARM support exists, but is not widely used and may be buggy (for example, [100], [84], [...
...Heap types never inherit the C call protocol because that would not be safe (heap types can be changed dynamically). Performance This PEP should not impact the performance of existing code (in the positive or negative sense). It is meant to allow efficient new code to be written, not to make existing code faster. Here are a few pointers to the python-dev mailing list where performance improvements are discussed: https://mail.python.org/pipermail/python-dev/2018-July/154571.html https://mail.p...
...heap type because that would not be safe (heap types can be changed dynamically). C API functions We list some relevant Python/C API macros and functions. Some of these are existing (possibly changed) functions, some are new: int PyBaseFunction_CheckFast(PyObject *op): return true if op is an instance of a class with the Py_TPFLAGS_BASEFUNCTION set. This is the function that you need to use to determine whether it is meaningful to access the base_function internals. int PyBaseFunction_Check(P...
...heap types, structseq types) * singletons (static) * singletons (initialized once) * cached objects non-objects * will not (or unlikely to) change after init * only used in the main thread * initialized lazily * pre-allocated buffers * state Those globals are spread between the core runtime, the builtin modules, and the stdlib extension modules. For a breakdown of the remaining globals, run: ./python Tools/c-analyzer/table-file.py Tools/c-analyzer/cpython/globals-to-fix.tsv Already Complete...
...heapq.heapreplace() API to compare the new value to the top of the heap? Outstanding Issues Require C99, so we can use // comments, named initializers, declare variables without introducing a new scope, among other benefits. (Also better support for IEEE floating point issues like NaN and infinities?) Remove support for old systems, including: BeOS, RISCOS, (SGI) Irix, Tru64 References [1](1, 2, 3, 4, 5) PyCon 2003 State of the Union: http://www.python.org/doc/essays/ppt/pycon2003/pyc...
...heapq, implements a heap queue. Thanks to Kevin O'Connor for the code and François Pinard for an entertaining write-up explaining the theory and practical uses of heaps. New encoding for the Palm OS character set: palmos. binascii.crc32() and the zipfile module had problems on some 64-bit platforms. These have been fixed. On a platform with 8-byte C longs, crc32() now returns a signed-extended 4-byte result, so that its value as a Python int is equal to the value computed a 32-bit platform....
...heap where needed. What's New in Python 2.1.1 (final) ? The following bugs were fixed: [ #441664 ] Python crash on del of a slice of a mmap [ #438050 ] configure doesn't look for poll.h in sys [ #437487 ] 2.1 build on Solaris fails if CC is set [ #441527 ] unixccompiler preprocessor broken What's New in Python 2.1.1c1 ? Python 2.1.1 comes with the new, GPL-compatible PSF licence. Several insecurities in dict comparison as well as a scoping bug, that could lead to the Python interpreter...
...heap objects ob_refcnt is part of the memory allocated for every object. However, _PyObject_HEAD_EXTRA is allocated only if CPython was built with Py_TRACE_REFS defined. PyGC_Head is allocated only if the object's type has Py_TPFLAGS_HAVE_GC set. Typically this is only container types (e.g. list). Also note that PyObject.ob_refcnt and _PyObject_HEAD_EXTRA are part of PyObject_HEAD. Reference Counting, with Cyclic Garbage Collection Garbage collection is a memory management feature of some ...
...heapq, implements a heap queue. Thanks to Kevin O'Connor for the code and Franחois Pinard for an entertaining write-up explaining the theory and practical uses of heaps. New encoding for the Palm OS character set: palmos. binascii.crc32() and the zipfile module had problems on some 64-bit platforms. These have been fixed. On a platform with 8-byte C longs, crc32() now returns a signed-extended 4-byte result, so that its value as a Python int is equal to the value computed a 32-bit platform....
...heap types), PEP 3121 (module state), and PEP 573 strategies for dealing with 3rd party C libraries that keep their own subinterpreter-incompatible global state Note that the documentation will play a large part in mitigating any negative impact that the new interpreters module might have on extension module maintainers. Also, the ImportError for incompatible extgension modules will have a message that clearly says it is due to missing subinterpreter compatibility and that extensions are not re...