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1""" 

2Array methods which are called by both the C-code for the method 

3and the Python code for the NumPy-namespace function 

4 

5""" 

6import warnings 

7from contextlib import nullcontext 

8 

9from numpy.core import multiarray as mu 

10from numpy.core import umath as um 

11from numpy.core.multiarray import asanyarray 

12from numpy.core import numerictypes as nt 

13from numpy.core import _exceptions 

14from numpy.core._ufunc_config import _no_nep50_warning 

15from numpy._globals import _NoValue 

16from numpy.compat import pickle, os_fspath 

17 

18# save those O(100) nanoseconds! 

19umr_maximum = um.maximum.reduce 

20umr_minimum = um.minimum.reduce 

21umr_sum = um.add.reduce 

22umr_prod = um.multiply.reduce 

23umr_any = um.logical_or.reduce 

24umr_all = um.logical_and.reduce 

25 

26# Complex types to -> (2,)float view for fast-path computation in _var() 

27_complex_to_float = { 

28 nt.dtype(nt.csingle) : nt.dtype(nt.single), 

29 nt.dtype(nt.cdouble) : nt.dtype(nt.double), 

30} 

31# Special case for windows: ensure double takes precedence 

32if nt.dtype(nt.longdouble) != nt.dtype(nt.double): 

33 _complex_to_float.update({ 

34 nt.dtype(nt.clongdouble) : nt.dtype(nt.longdouble), 

35 }) 

36 

37# avoid keyword arguments to speed up parsing, saves about 15%-20% for very 

38# small reductions 

39def _amax(a, axis=None, out=None, keepdims=False, 

40 initial=_NoValue, where=True): 

41 return umr_maximum(a, axis, None, out, keepdims, initial, where) 

42 

43def _amin(a, axis=None, out=None, keepdims=False, 

44 initial=_NoValue, where=True): 

45 return umr_minimum(a, axis, None, out, keepdims, initial, where) 

46 

47def _sum(a, axis=None, dtype=None, out=None, keepdims=False, 

48 initial=_NoValue, where=True): 

49 return umr_sum(a, axis, dtype, out, keepdims, initial, where) 

50 

51def _prod(a, axis=None, dtype=None, out=None, keepdims=False, 

52 initial=_NoValue, where=True): 

53 return umr_prod(a, axis, dtype, out, keepdims, initial, where) 

54 

55def _any(a, axis=None, dtype=None, out=None, keepdims=False, *, where=True): 

56 # Parsing keyword arguments is currently fairly slow, so avoid it for now 

57 if where is True: 

58 return umr_any(a, axis, dtype, out, keepdims) 

59 return umr_any(a, axis, dtype, out, keepdims, where=where) 

60 

61def _all(a, axis=None, dtype=None, out=None, keepdims=False, *, where=True): 

62 # Parsing keyword arguments is currently fairly slow, so avoid it for now 

63 if where is True: 

64 return umr_all(a, axis, dtype, out, keepdims) 

65 return umr_all(a, axis, dtype, out, keepdims, where=where) 

66 

67def _count_reduce_items(arr, axis, keepdims=False, where=True): 

68 # fast-path for the default case 

69 if where is True: 

70 # no boolean mask given, calculate items according to axis 

71 if axis is None: 

72 axis = tuple(range(arr.ndim)) 

73 elif not isinstance(axis, tuple): 

74 axis = (axis,) 

75 items = 1 

76 for ax in axis: 

77 items *= arr.shape[mu.normalize_axis_index(ax, arr.ndim)] 

78 items = nt.intp(items) 

79 else: 

80 # TODO: Optimize case when `where` is broadcast along a non-reduction 

81 # axis and full sum is more excessive than needed. 

82 

83 # guarded to protect circular imports 

84 from numpy.lib.stride_tricks import broadcast_to 

85 # count True values in (potentially broadcasted) boolean mask 

86 items = umr_sum(broadcast_to(where, arr.shape), axis, nt.intp, None, 

87 keepdims) 

88 return items 

89 

90def _clip(a, min=None, max=None, out=None, **kwargs): 

91 if min is None and max is None: 

92 raise ValueError("One of max or min must be given") 

93 

94 if min is None: 

95 return um.minimum(a, max, out=out, **kwargs) 

96 elif max is None: 

97 return um.maximum(a, min, out=out, **kwargs) 

98 else: 

99 return um.clip(a, min, max, out=out, **kwargs) 

100 

101def _mean(a, axis=None, dtype=None, out=None, keepdims=False, *, where=True): 

102 arr = asanyarray(a) 

103 

104 is_float16_result = False 

105 

106 rcount = _count_reduce_items(arr, axis, keepdims=keepdims, where=where) 

107 if rcount == 0 if where is True else umr_any(rcount == 0, axis=None): 

108 warnings.warn("Mean of empty slice.", RuntimeWarning, stacklevel=2) 

109 

110 # Cast bool, unsigned int, and int to float64 by default 

111 if dtype is None: 

112 if issubclass(arr.dtype.type, (nt.integer, nt.bool_)): 

113 dtype = mu.dtype('f8') 

114 elif issubclass(arr.dtype.type, nt.float16): 

115 dtype = mu.dtype('f4') 

116 is_float16_result = True 

117 

118 ret = umr_sum(arr, axis, dtype, out, keepdims, where=where) 

119 if isinstance(ret, mu.ndarray): 

120 with _no_nep50_warning(): 

121 ret = um.true_divide( 

122 ret, rcount, out=ret, casting='unsafe', subok=False) 

123 if is_float16_result and out is None: 

124 ret = arr.dtype.type(ret) 

125 elif hasattr(ret, 'dtype'): 

126 if is_float16_result: 

127 ret = arr.dtype.type(ret / rcount) 

128 else: 

129 ret = ret.dtype.type(ret / rcount) 

130 else: 

131 ret = ret / rcount 

132 

133 return ret 

134 

135def _var(a, axis=None, dtype=None, out=None, ddof=0, keepdims=False, *, 

136 where=True): 

137 arr = asanyarray(a) 

138 

139 rcount = _count_reduce_items(arr, axis, keepdims=keepdims, where=where) 

140 # Make this warning show up on top. 

141 if ddof >= rcount if where is True else umr_any(ddof >= rcount, axis=None): 

142 warnings.warn("Degrees of freedom <= 0 for slice", RuntimeWarning, 

143 stacklevel=2) 

144 

145 # Cast bool, unsigned int, and int to float64 by default 

146 if dtype is None and issubclass(arr.dtype.type, (nt.integer, nt.bool_)): 

147 dtype = mu.dtype('f8') 

148 

149 # Compute the mean. 

150 # Note that if dtype is not of inexact type then arraymean will 

151 # not be either. 

152 arrmean = umr_sum(arr, axis, dtype, keepdims=True, where=where) 

153 # The shape of rcount has to match arrmean to not change the shape of out 

154 # in broadcasting. Otherwise, it cannot be stored back to arrmean. 

155 if rcount.ndim == 0: 

156 # fast-path for default case when where is True 

157 div = rcount 

158 else: 

159 # matching rcount to arrmean when where is specified as array 

160 div = rcount.reshape(arrmean.shape) 

161 if isinstance(arrmean, mu.ndarray): 

162 with _no_nep50_warning(): 

163 arrmean = um.true_divide(arrmean, div, out=arrmean, 

164 casting='unsafe', subok=False) 

165 elif hasattr(arrmean, "dtype"): 

166 arrmean = arrmean.dtype.type(arrmean / rcount) 

167 else: 

168 arrmean = arrmean / rcount 

169 

170 # Compute sum of squared deviations from mean 

171 # Note that x may not be inexact and that we need it to be an array, 

172 # not a scalar. 

173 x = asanyarray(arr - arrmean) 

174 

175 if issubclass(arr.dtype.type, (nt.floating, nt.integer)): 

176 x = um.multiply(x, x, out=x) 

177 # Fast-paths for built-in complex types 

178 elif x.dtype in _complex_to_float: 

179 xv = x.view(dtype=(_complex_to_float[x.dtype], (2,))) 

180 um.multiply(xv, xv, out=xv) 

181 x = um.add(xv[..., 0], xv[..., 1], out=x.real).real 

182 # Most general case; includes handling object arrays containing imaginary 

183 # numbers and complex types with non-native byteorder 

184 else: 

185 x = um.multiply(x, um.conjugate(x), out=x).real 

186 

187 ret = umr_sum(x, axis, dtype, out, keepdims=keepdims, where=where) 

188 

189 # Compute degrees of freedom and make sure it is not negative. 

190 rcount = um.maximum(rcount - ddof, 0) 

191 

192 # divide by degrees of freedom 

193 if isinstance(ret, mu.ndarray): 

194 with _no_nep50_warning(): 

195 ret = um.true_divide( 

196 ret, rcount, out=ret, casting='unsafe', subok=False) 

197 elif hasattr(ret, 'dtype'): 

198 ret = ret.dtype.type(ret / rcount) 

199 else: 

200 ret = ret / rcount 

201 

202 return ret 

203 

204def _std(a, axis=None, dtype=None, out=None, ddof=0, keepdims=False, *, 

205 where=True): 

206 ret = _var(a, axis=axis, dtype=dtype, out=out, ddof=ddof, 

207 keepdims=keepdims, where=where) 

208 

209 if isinstance(ret, mu.ndarray): 

210 ret = um.sqrt(ret, out=ret) 

211 elif hasattr(ret, 'dtype'): 

212 ret = ret.dtype.type(um.sqrt(ret)) 

213 else: 

214 ret = um.sqrt(ret) 

215 

216 return ret 

217 

218def _ptp(a, axis=None, out=None, keepdims=False): 

219 return um.subtract( 

220 umr_maximum(a, axis, None, out, keepdims), 

221 umr_minimum(a, axis, None, None, keepdims), 

222 out 

223 ) 

224 

225def _dump(self, file, protocol=2): 

226 if hasattr(file, 'write'): 

227 ctx = nullcontext(file) 

228 else: 

229 ctx = open(os_fspath(file), "wb") 

230 with ctx as f: 

231 pickle.dump(self, f, protocol=protocol) 

232 

233def _dumps(self, protocol=2): 

234 return pickle.dumps(self, protocol=protocol)