Coverage for install/scipp/core/like.py: 47%

1# SPDX-License-Identifier: BSD-3-Clause 

2# Copyright (c) 2023 Scipp contributors (https://github.com/scipp) 

3 

4from typing import Any, TypeVar 

5 

6from .concepts import rewrap_output_data 

7from .cpp_classes import DataArray, Variable 

8from .variable import empty, full, ones, zeros 

9 

10_T = TypeVar('_T', Variable, DataArray) 

11 

12 

13def zeros_like(obj: _T, /) -> _T: 

14 """Return a new object with the same dims, shape, unit, 

15 and dtype as the input and all elements initialized to 0. 

16 

17 If the input has variances, all variances in the output are set to 0. 

18 If the input is a :class:`DataArray`, coordinates and attributes are shallow-copied 

19 and masks are deep-copied. 

20 

21 Parameters 

22 ---------- 

23 obj: scipp.Variable | scipp.DataArray 

24 Input object defining dims, shape, unit, and dtype of the output. 

25 

26 Returns 

27 ------- 

28 : Same type as input 

29 New object of zeros. 

30 

31 See Also 

32 -------- 

33 scipp.zeros: 

34 Create zeros but based on given dims and shape. 

35 scipp.ones_like: 

36 Create an object initialized with ones. 

37 scipp.full_like: 

38 Create an object filled with a given value. 

39 scipp.empty_like: 

40 Create an object with uninitialized elements. 

41 """ 

42 new_values = zeros( 

43 dims=obj.dims, 

44 shape=obj.shape, 

45 unit=obj.unit, 

46 dtype=obj.dtype, 

47 with_variances=obj.variances is not None, 

48 ) 

49 return rewrap_output_data(obj, new_values) 

50 

51 

52def ones_like(obj: _T, /) -> _T: 

53 """Return a new object with the same dims, shape, unit, 

54 and dtype as the input and all elements initialized to 1. 

55 

56 If the input has variances, all variances in the output are set to 1. 

57 If the input is a :class:`DataArray`, coordinates and attributes are shallow-copied 

58 and masks are deep-copied. 

59 

60 Parameters 

61 ---------- 

62 obj: scipp.Variable | scipp.DataArray 

63 Input object defining dims, shape, unit, and dtype of the output. 

64 

65 Returns 

66 ------- 

67 : Same type as input 

68 New object of ones. 

69 

70 See Also 

71 -------- 

72 scipp.ones: 

73 Create ones but based on given dims and shape. 

74 scipp.zeros_like: 

75 Create an object initialized with zeros. 

76 scipp.full_like: 

77 Create an object filled with a given value. 

78 scipp.empty_like: 

79 Create an object with uninitialized elements. 

80 """ 

81 new_values = ones( 

82 dims=obj.dims, 

83 shape=obj.shape, 

84 unit=obj.unit, 

85 dtype=obj.dtype, 

86 with_variances=obj.variances is not None, 

87 ) 

88 return rewrap_output_data(obj, new_values) 

89 

90 

91def empty_like(obj: _T, /) -> _T: 

92 """Return a new object with the same dims, shape, unit, 

93 and dtype as the input and all elements uninitialized. 

94 

95 If the input has variances, all variances in the output exist but are uninitialized. 

96 If the input is a :class:`DataArray`, coordinates and attributes are shallow-copied 

97 and masks are deep-copied. 

98 

99 Warning 

100 ------- 

101 Reading from any elements before writing to them produces undefined results. 

102 

103 Parameters 

104 ---------- 

105 obj: scipp.Variable | scipp.DataArray 

106 Input object defining dims, shape, unit, and dtype of the output 

107 

108 Returns 

109 ------- 

110 : Same type as input 

111 New object with uninitialized values and maybe variances. 

112 

113 See Also 

114 -------- 

115 scipp.empty: 

116 Create an uninitialized object based on given dims and shape. 

117 scipp.zeros_like: 

118 Create an object initialized with zeros. 

119 scipp.ones_like: 

120 Create an object initialized with ones. 

121 scipp.full_like: 

122 Create an object filled with a given value. 

123 """ 

124 new_values = empty( 

125 dims=obj.dims, 

126 shape=obj.shape, 

127 unit=obj.unit, 

128 dtype=obj.dtype, 

129 with_variances=obj.variances is not None, 

130 ) 

131 return rewrap_output_data(obj, new_values) 

132 

133 

134def full_like(obj: _T, /, value: Any, *, variance: Any = None) -> _T: 

135 """Return a new object with the same dims, shape, unit, 

136 and dtype as the input and all elements initialized to the given value. 

137 

138 If the input is a :class:`DataArray`, coordinates and attributes are shallow-copied 

139 and masks are deep-copied. 

140 

141 Parameters 

142 ---------- 

143 obj: scipp.Variable | scipp.DataArray 

144 Input object defining dims, shape, unit, and dtype of the output 

145 value: 

146 The value to fill the data with. 

147 variance: 

148 The variance to fill the Variable with. If None 

149 or not provided, the variances will not be set. 

150 

151 Returns 

152 ------- 

153 : Same type as input 

154 New object with elements set to given values and variances. 

155 

156 See Also 

157 -------- 

158 scipp.full: 

159 Create an object filled with given value based on given dims and shape. 

160 scipp.zeros_like: 

161 Create an object initialized with zeros. 

162 scipp.ones_like: 

163 Create an object initialized with ones. 

164 scipp.empty_like: 

165 Create an object with uninitialized elements. 

166 """ 

167 new_values = full( 

168 dims=obj.dims, 

169 shape=obj.shape, 

170 unit=obj.unit, 

171 dtype=obj.dtype, 

172 value=value, 

173 variance=variance, 

174 ) 

175 return rewrap_output_data(obj, new_values)