I'm trying to do something ... unusual.
gdb support scripting with Python. From within my python script, I can get the address of a contiguous area of memory that stores a fortran array. I want to creat a NumPy array using "frombuffer". I see that the CPython API supports the creation of a buffer, but, is there an easier, more direct, way?
-Mathew
I'm trying to do something ... unusual.
gdb support scripting with Python. From within my python script, I can get the address of a contiguous area of memory that stores a fortran array. I want to creat a NumPy array using "frombuffer". I see that the CPython API supports the creation of a buffer, but, is there an easier, more direct, way?
Here's how I do a similar task: numpy.ndarray(shape, dtype=dtype, buffer=(ctypes.c_char*size_in_bytes).from_address(address))
You may need the strides or order parameters, as well.
Perhaps there's an easier way to create a buffer from an integer memory address, but this seems pretty straightforward.
Zach
Thank a lot. I was wading through the Python C API. This is much simpler.
-Mathew
On Fri, Sep 24, 2010 at 10:21 AM, Zachary Pincus zachary.pincus@yale.edu wrote:
I'm trying to do something ... unusual.
gdb support scripting with Python. From within my python script, I can get the address of a contiguous area of memory that stores a fortran array. I want to creat a NumPy array using "frombuffer". I see that the CPython API supports the creation of a buffer, but, is there an easier, more direct, way?
Here's how I do a similar task: numpy.ndarray(shape, dtype=dtype, buffer=(ctypes.c_char*size_in_bytes).from_address(address))
You may need the strides or order parameters, as well.
Perhaps there's an easier way to create a buffer from an integer memory address, but this seems pretty straightforward.
Zach _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
On Fri, Sep 24, 2010 at 11:25, Mathew Yeates mat.yeates@gmail.com wrote:
I'm trying to do something ... unusual.
gdb support scripting with Python. From within my python script, I can get the address of a contiguous area of memory that stores a fortran array. I want to creat a NumPy array using "frombuffer". I see that the CPython API supports the creation of a buffer, but, is there an easier, more direct, way?
You can also make an object with an .__array_interface__ attribute describing the data.
[~] |5> x = np.arange(10)
[~] |6> x.__array_interface__
{'data': (68583072, False), 'descr': [('', '<i4')], 'shape': (10,), 'strides': None, 'typestr': '<i4', 'version': 3}
[~] |7> np.lib.stride_tricks.DummyArray?? Type: type Base Class: <type 'type'> String Form: <class 'numpy.lib.stride_tricks.DummyArray'> Namespace: Interactive File: /Library/Frameworks/Python.framework/Versions/6.1/lib/python2.6/site-packages/numpy/lib/stride_tricks.py Source: class DummyArray(object): """ Dummy object that just exists to hang __array_interface__ dictionaries and possibly keep alive a reference to a base array. """ def __init__(self, interface, base=None): self.__array_interface__ = interface self.base = base Constructor information: Definition: np.lib.stride_tricks.DummyArray(self, interface, base=None)
Then np.asarray() will consume that object to make an ndarray that references the given memory.
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Mathew Yeates -
Robert Kern -
Zachary Pincus