FilesExpand file tree

 master

/

map.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

171 lines (139 loc) · 5.28 KB

 master

/

map.py

Copy path

Top

File metadata and controls

• Code
• Blame

171 lines (139 loc) · 5.28 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

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

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

# encoding: utf-8

"""Classes used in scattering and gathering sequences.

Scattering consists of partitioning a sequence and sending the various

pieces to individual nodes in a cluster.

Authors:

* Brian Granger

* MinRK

"""

#-------------------------------------------------------------------------------

# Copyright (C) 2008-2011 The IPython Development Team

#

# Distributed under the terms of the BSD License. The full license is in

# the file COPYING, distributed as part of this software.

#-------------------------------------------------------------------------------

#-------------------------------------------------------------------------------

# Imports

#-------------------------------------------------------------------------------

from __future__ import division

import types

from itertools import islice

from IPython.utils.data import flatten as utils_flatten

#-------------------------------------------------------------------------------

# Figure out which array packages are present and their array types

#-------------------------------------------------------------------------------

arrayModules = []

try:

import Numeric

except ImportError:

pass

else:

arrayModules.append({'module':Numeric, 'type':Numeric.arraytype})

try:

import numpy

except ImportError:

pass

else:

arrayModules.append({'module':numpy, 'type':numpy.ndarray})

try:

import numarray

except ImportError:

pass

else:

arrayModules.append({'module':numarray,

'type':numarray.numarraycore.NumArray})

class Map:

"""A class for partitioning a sequence using a map."""

def getPartition(self, seq, p, q):

"""Returns the pth partition of q partitions of seq."""

# Test for error conditions here

if p<0 or p>=q:

print "No partition exists."

return

remainder = len(seq)%q

basesize = len(seq)//q

hi = []

lo = []

for n in range(q):

if n < remainder:

lo.append(n * (basesize + 1))

hi.append(lo[-1] + basesize + 1)

else:

lo.append(n*basesize + remainder)

hi.append(lo[-1] + basesize)

try:

result = seq[lo[p]:hi[p]]

except TypeError:

# some objects (iterators) can't be sliced,

# use islice:

result = list(islice(seq, lo[p], hi[p]))

return result

def joinPartitions(self, listOfPartitions):

return self.concatenate(listOfPartitions)

def concatenate(self, listOfPartitions):

testObject = listOfPartitions[0]

# First see if we have a known array type

for m in arrayModules:

#print m

if isinstance(testObject, m['type']):

return m['module'].concatenate(listOfPartitions)

# Next try for Python sequence types

if isinstance(testObject, (types.ListType, types.TupleType)):

return utils_flatten(listOfPartitions)

# If we have scalars, just return listOfPartitions

return listOfPartitions

class RoundRobinMap(Map):

"""Partitions a sequence in a roun robin fashion.

This currently does not work!

"""

def getPartition(self, seq, p, q):

# if not isinstance(seq,(list,tuple)):

# raise NotImplementedError("cannot RR partition type %s"%type(seq))

return seq[p:len(seq):q]

#result = []

#for i in range(p,len(seq),q):

# result.append(seq[i])

#return result

def joinPartitions(self, listOfPartitions):

testObject = listOfPartitions[0]

# First see if we have a known array type

for m in arrayModules:

#print m

if isinstance(testObject, m['type']):

return self.flatten_array(m['type'], listOfPartitions)

if isinstance(testObject, (types.ListType, types.TupleType)):

return self.flatten_list(listOfPartitions)

return listOfPartitions

def flatten_array(self, klass, listOfPartitions):

test = listOfPartitions[0]

shape = list(test.shape)

shape[0] = sum([ p.shape[0] for p in listOfPartitions])

A = klass(shape)

N = shape[0]

q = len(listOfPartitions)

for p,part in enumerate(listOfPartitions):

A[p:N:q] = part

return A

def flatten_list(self, listOfPartitions):

flat = []

for i in range(len(listOfPartitions[0])):

flat.extend([ part[i] for part in listOfPartitions if len(part) > i ])

return flat

#lengths = [len(x) for x in listOfPartitions]

#maxPartitionLength = len(listOfPartitions[0])

#numberOfPartitions = len(listOfPartitions)

#concat = self.concatenate(listOfPartitions)

#totalLength = len(concat)

#result = []

#for i in range(maxPartitionLength):

# result.append(concat[i:totalLength:maxPartitionLength])

# return self.concatenate(listOfPartitions)

def mappable(obj):

"""return whether an object is mappable or not."""

if isinstance(obj, (tuple,list)):

return True

for m in arrayModules:

if isinstance(obj,m['type']):

return True

return False

dists = {'b':Map,'r':RoundRobinMap}