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Diffstat (limited to 'doc/source/reference/c-api.array.rst')
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diff --git a/doc/source/reference/c-api.array.rst b/doc/source/reference/c-api.array.rst index da573f0b4..d3e8fe348 100644 --- a/doc/source/reference/c-api.array.rst +++ b/doc/source/reference/c-api.array.rst @@ -1766,6 +1766,29 @@ Array Functions *op1*, 2 - return all possible shifts (any overlap at all is accepted). + .. rubric:: Notes + + This does not compute the usual correlation: if op2 is larger than op1, the + arguments are swapped, and the conjugate is never taken for complex arrays. + See PyArray_Correlate2 for the usual signal processing correlation. + +.. cfunction:: PyObject* PyArray_Correlate2(PyObject* op1, PyObject* op2, int mode) + + Updated version of PyArray_Correlate, which uses the usual definition of + correlation for 1d arrays. The correlation is computed at each output point + by multiplying *op1* by a shifted version of *op2* and summing the result. + As a result of the shift, needed values outside of the defined range of + *op1* and *op2* are interpreted as zero. The mode determines how many + shifts to return: 0 - return only shifts that did not need to assume zero- + values; 1 - return an object that is the same size as *op1*, 2 - return all + possible shifts (any overlap at all is accepted). + + .. rubric:: Notes + + Compute z as follows:: + + z[k] = sum_n op1[n] * conj(op2[n+k]) + .. cfunction:: PyObject* PyArray_Where(PyObject* condition, PyObject* x, PyObject* y) If both ``x`` and ``y`` are ``NULL``, then return |