# pypy / lib_pypy / numpypy / core / _methods.py

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98``` ```# Array methods which are called by the both the C-code for the method # and the Python code for the NumPy-namespace function import _numpypy as mu um = mu #from numpypy.core import umath as um from numpypy.core.numeric import asanyarray def _amax(a, axis=None, out=None, skipna=False, keepdims=False): return um.maximum.reduce(a, axis=axis, out=out, skipna=skipna, keepdims=keepdims) def _amin(a, axis=None, out=None, skipna=False, keepdims=False): return um.minimum.reduce(a, axis=axis, out=out, skipna=skipna, keepdims=keepdims) def _sum(a, axis=None, dtype=None, out=None, skipna=False, keepdims=False): return um.add.reduce(a, axis=axis, dtype=dtype, out=out, skipna=skipna, keepdims=keepdims) def _prod(a, axis=None, dtype=None, out=None, skipna=False, keepdims=False): return um.multiply.reduce(a, axis=axis, dtype=dtype, out=out, skipna=skipna, keepdims=keepdims) def _mean(a, axis=None, dtype=None, out=None, skipna=False, keepdims=False): arr = asanyarray(a) # Upgrade bool, unsigned int, and int to float64 if dtype is None and arr.dtype.kind in ['b','u','i']: ret = um.add.reduce(arr, axis=axis, dtype='f8', out=out, skipna=skipna, keepdims=keepdims) else: ret = um.add.reduce(arr, axis=axis, dtype=dtype, out=out, skipna=skipna, keepdims=keepdims) rcount = mu.count_reduce_items(arr, axis=axis, skipna=skipna, keepdims=keepdims) if isinstance(ret, mu.ndarray): ret = um.true_divide(ret, rcount, casting='unsafe', subok=False) else: ret = ret / float(rcount) return ret def _var(a, axis=None, dtype=None, out=None, ddof=0, skipna=False, keepdims=False): arr = asanyarray(a) # First compute the mean, saving 'rcount' for reuse later if dtype is None and arr.dtype.kind in ['b','u','i']: arrmean = um.add.reduce(arr, axis=axis, dtype='f8', skipna=skipna, keepdims=True) else: arrmean = um.add.reduce(arr, axis=axis, dtype=dtype, skipna=skipna, keepdims=True) rcount = mu.count_reduce_items(arr, axis=axis, skipna=skipna, keepdims=True) if isinstance(arrmean, mu.ndarray): arrmean = um.true_divide(arrmean, rcount, casting='unsafe', subok=False) else: arrmean = arrmean / float(rcount) # arr - arrmean x = arr - arrmean # (arr - arrmean) ** 2 if arr.dtype.kind == 'c': x = um.multiply(x, um.conjugate(x)).real else: x = um.multiply(x, x) # add.reduce((arr - arrmean) ** 2, axis) ret = um.add.reduce(x, axis=axis, dtype=dtype, out=out, skipna=skipna, keepdims=keepdims) # add.reduce((arr - arrmean) ** 2, axis) / (n - ddof) if not keepdims and isinstance(rcount, mu.ndarray): rcount = rcount.squeeze(axis=axis) rcount -= ddof if isinstance(ret, mu.ndarray): ret = um.true_divide(ret, rcount, casting='unsafe', subok=False) else: ret = ret / float(rcount) return ret def _std(a, axis=None, dtype=None, out=None, ddof=0, skipna=False, keepdims=False): ret = _var(a, axis=axis, dtype=dtype, out=out, ddof=ddof, skipna=skipna, keepdims=keepdims) if isinstance(ret, mu.ndarray): ret = um.sqrt(ret) else: ret = um.sqrt(ret) return ret ```