source: fact/tools/pyscripts/pyfact/factfits.py@ 13412

Last change on this file since 13412 was 13407, checked in by neise, 13 years ago
added some comments
  • Property svn:executable set to *
File size: 13.3 KB
Line 
1#!/usr/bin/python -itt
2import numpy as np
3import pprint
4import ctypes
5
6from ROOT import gSystem
7gSystem.Load('pyfits_h.so')
8from ROOT import *
9
10class FactFits( fits ):
11 """ -Fact Fits File-
12 A Python wrapper for the fits-class implemented in pyfits.h
13 provides easy access to the fits file meta data.
14 * dictionary of file metadata - self.meta
15 * dict of table metadata - self.columns
16 * variable table column access, thus possibly increased speed while looping
17 """
18 def __init__(self, path):
19 """ creates meta and columns dictionaries
20 """
21 self.path = path
22 try:
23 fits.__init__(self,path)
24 except IOError:
25 print 'problem accessing data file: ', data_file_name
26 raise # stop ! no data
27
28 self.meta = self._make_meta_dict()
29 self.columns = self._make_columns_dict()
30
31 self.treat_meta_dict()
32
33
34 # list of columns, which are already registered
35 # see method register()
36 self._registered_cols = []
37 # dict of column data, this is used, in order to be able to remove
38 # the ctypes of
39 self._table_cols = {}
40
41 # I need to count the rows, since the normal loop mechanism seems not to work.
42 self._current_row = 0
43
44 self.stacked_cols = {}
45
46 def _make_meta_dict(self):
47 """ This method retrieves meta information about the fits file and
48 stores this information in a dict
49 return: dict
50 key: string - all capital letters
51 value: tuple( numerical value, string comment)
52 """
53 # intermediate variables for file metadata dict generation
54 keys=self.GetPy_KeyKeys()
55 values=self.GetPy_KeyValues()
56 comments=self.GetPy_KeyComments()
57 types=self.GetPy_KeyTypes()
58
59 if len(keys) != len(values):
60 raise TypeError('len(keys)',len(keys),' != len(values)', len(values))
61 if len(keys) != len(types):
62 raise TypeError('len(keys)',len(keys),' != len(types)', len(types))
63 if len(keys) != len(comments):
64 raise TypeError('len(keys)',len(keys),' != len(comments)', len(comments))
65
66 meta_dict = {}
67 for i in range(len(keys)):
68 type = types[i]
69 if type == 'I':
70 value = int(values[i])
71 elif type == 'F':
72 value = float(values[i])
73 elif type == 'B':
74 if values[i] == 'T':
75 value = True
76 elif values[i] == 'F':
77 value = False
78 else:
79 raise TypeError("meta-type is 'B', but meta-value is neither 'T' nor 'F'. meta-value:",values[i])
80 elif type == 'T':
81 value = values[i]
82 else:
83 raise TypeError("unknown meta-type: known meta types are: I,F,B and T. meta-type:",type)
84 meta_dict[keys[i]]=(value, comments[i])
85 return meta_dict
86
87
88 def _make_columns_dict(self):
89 """ This method retrieves information about the columns
90 stored inside the fits files internal binary table.
91 returns: dict
92 key: string column name -- all capital letters
93 values: tuple(
94 number of elements in table field - integer
95 size of element in bytes -- this is not really interesting for any user
96 might be ommited in future versions
97 type - a single character code -- should be translated into
98 a comrehensible word
99 unit - string like 'mV' or 'ADC count'
100 """
101 # intermediate variables for file table-metadata dict generation
102 keys=self.GetPy_ColumnKeys()
103 #offsets=self.GetPy_ColumnOffsets() #not needed on python level...
104 nums=self.GetPy_ColumnNums()
105 sizes=self.GetPy_ColumnSizes()
106 types=self.GetPy_ColumnTypes()
107 units=self.GetPy_ColumnUnits()
108
109 # zip the values
110 values = zip(nums,sizes,types,units)
111 # create the columns dictionary
112 columns = dict(zip(keys ,values))
113 return columns
114
115 def stack(self, on=True):
116 self.next()
117 for col in self._registered_cols:
118 if isinstance( self.dict[col], type(np.array('')) ):
119 self.stacked_cols[col] = self.dict[col]
120 else:
121# elif isinstance(self.dict[col], ctypes._SimpleCData):
122 self.stacked_cols[col] = np.array(self.dict[col])
123# else:
124# raise TypeError("I don't know how to stack "+col+". It is of type: "+str(type(self.dict[col])))
125
126 def register(self, input_str):
127 columns = self.columns
128 if input_str.lower() == 'all':
129 for col in columns:
130 self._register(col)
131 else:
132 #check if colname is in columns:
133 if input_str not in columns:
134 error_msg = 'colname:'+ input_str +' is not a column in the binary table.\n'
135 error_msg+= 'possible colnames are\n'
136 for key in columns:
137 error_msg += key+'\n'
138 raise KeyError(error_msg)
139 else:
140 self._register(input_str)
141
142 # 'private' method, do not use
143 def _register( self, colname):
144 columns = self.columns
145 local = None
146
147 number_of_elements = int(columns[colname][0])
148 size_of_elements_in_bytes = int(columns[colname][1])
149 ctypecode_of_elements = columns[colname][2]
150 physical_unit_of_elements = columns[colname][3]
151
152 # snippet from the C++ source code, or header file to be precise:
153 #case 'L': gLog << "bool(8)"; break;
154 #case 'B': gLog << "byte(8)"; break;
155 #case 'I': gLog << "short(16)"; break;
156 #case 'J': gLog << "int(32)"; break;
157 #case 'K': gLog << "int(64)"; break;
158 #case 'E': gLog << "float(32)"; break;
159 #case 'D': gLog << "double(64)"; break;
160
161
162
163 # the fields inside the columns can either contain single numbers,
164 # or whole arrays of numbers as well.
165 # we treat single elements differently...
166 if number_of_elements == 1:
167 # allocate some memory for a single number according to its type
168 if ctypecode_of_elements == 'J': # J is for a 4byte int, i.e. an unsigned long
169 local = ctypes.c_ulong()
170 un_c_type = long
171 elif ctypecode_of_elements == 'I': # I is for a 2byte int, i.e. an unsinged int
172 local = ctypes.c_ushort()
173 un_c_type = int
174 elif ctypecode_of_elements == 'B': # B is for a byte
175 local = ctypes.c_ubyte()
176 un_c_type = int
177 elif ctypecode_of_elements == 'D':
178 local = ctypes.c_double()
179 un_c_type = float
180 elif ctypecode_of_elements == 'E':
181 local = ctypes.c_float()
182 un_c_type = float
183 elif ctypecode_of_elements == 'A':
184 local = ctypes.c_uchar()
185 un_c_type = chr
186 elif ctypecode_of_elements == 'K':
187 local = ctypes.c_ulonglong()
188 un_c_type = long
189 else:
190 raise TypeError('unknown ctypecode_of_elements:',ctypecode_of_elements)
191 else:
192 if ctypecode_of_elements == 'B': # B is for a byte
193 nptype = np.int8
194 elif ctypecode_of_elements == 'A': # A is for a char .. but I don't know how to handle it
195 nptype = np.int8
196 elif ctypecode_of_elements == 'I': # I is for a 2byte int
197 nptype = np.int16
198 elif ctypecode_of_elements == 'J': # J is for a 4byte int
199 nptype = np.int32
200 elif ctypecode_of_elements == 'K': # B is for a byte
201 nptype = np.int64
202 elif ctypecode_of_elements == 'E': # B is for a byte
203 nptype = np.float32
204 elif ctypecode_of_elements == 'D': # B is for a byte
205 nptype = np.float64
206 else:
207 raise TypeError('unknown ctypecode_of_elements:',ctypecode_of_elements)
208 local = np.zeros( number_of_elements, nptype)
209
210 # Set the Pointer Address
211 self.SetPtrAddress(colname, local)
212 self._table_cols[colname] = local
213 if number_of_elements > 1:
214 self.__dict__[colname] = local
215 self.dict[colname] = local
216 else:
217 # remove any traces of ctypes:
218 self.__dict__[colname] = local.value
219 self.dict[colname] = local.value
220 self._registered_cols.append(colname)
221
222
223 def treat_meta_dict(self):
224 """make 'interesting' meta information available like normal members.
225 non interesting are:
226 TFORM, TUNIT, and TTYPE
227 since these are available via the columns dict.
228 """
229
230 self.number_of_rows = self.meta['NAXIS2'][0]
231 self.number_of_columns = self.meta['TFIELDS'][0]
232
233 # there are some information in the meta dict, which are alsways there:
234 # there are regarded as not interesting:
235 uninteresting_meta = {}
236 uninteresting_meta['arraylike'] = {}
237 uninteresting = ['NAXIS', 'NAXIS1', 'NAXIS2',
238 'TFIELDS',
239 'XTENSION','EXTNAME','EXTREL',
240 'BITPIX', 'PCOUNT', 'GCOUNT',
241 'ORIGIN',
242 'PACKAGE', 'COMPILED', 'CREATOR',
243 'TELESCOP','TIMESYS','TIMEUNIT','VERSION']
244 for key in uninteresting:
245 if key in self.meta:
246 uninteresting_meta[key]=self.meta[key]
247 del self.meta[key]
248
249 # the table meta data contains
250
251
252 # shortcut to access the meta dict. But this needs to
253 # be cleaned up quickly!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
254 meta = self.meta
255
256 # loop over keys:
257 # * try to find array-like keys
258 arraylike = {}
259 singlelike = []
260 for key in self.meta:
261 stripped = key.rstrip('1234567890')
262 if stripped == key:
263 singlelike.append(key)
264 else:
265 if stripped not in arraylike:
266 arraylike[stripped] = 0
267 else:
268 arraylike[stripped] += 1
269 newmeta = {}
270 for key in singlelike:
271 newmeta[key.lower()] = meta[key]
272 for key in arraylike:
273 uninteresting_meta['arraylike'][key.lower()] = []
274 for i in range(arraylike[key]+1):
275 if key+str(i) in meta:
276 uninteresting_meta['arraylike'][key.lower()].append(meta[key+str(i)])
277 self.ui_meta = uninteresting_meta
278 # make newmeta self
279 for key in newmeta:
280 self.__dict__[key]=newmeta[key]
281
282 dict = self.__dict__.copy()
283 del dict['meta']
284 del dict['ui_meta']
285 self.dict = dict
286
287 def __iter__(self):
288 """ iterator """
289 return self
290
291 def next(self):
292 """ used by __iter__ """
293 # Here one might check, if looping makes any sense, and if not
294 # one could stop looping or so...
295 # like this:
296 #
297 # if len(self._registered_cols) == 0:
298 # print 'warning: looping without any registered columns'
299 if self._current_row < self.number_of_rows:
300 if self.GetNextRow() == False:
301 raise StopIteration
302 for col in self._registered_cols:
303 if isinstance(self._table_cols[col], ctypes._SimpleCData):
304 self.__dict__[col] = self._table_cols[col].value
305 self.dict[col] = self._table_cols[col].value
306
307 for col in self.stacked_cols:
308 if isinstance(self.dict[col], type(np.array(''))):
309 self.stacked_cols[col] = np.vstack( (self.stacked_cols[col],self.dict[col]) )
310 else:
311 self.stacked_cols[col] = np.vstack( (self.stacked_cols[col],np.array(self.dict[col])) )
312 self._current_row += 1
313 else:
314 raise StopIteration
315 return self
316
317 def show(self):
318 pprint.pprint(self.dict)
319
320if __name__ == '__main__':
321 import sys
322 if len(sys.argv) == 1:
323 print 'usage:', sys.argv[0], 'fits-file-name'
324
325 file = FactFits(sys.argv[1])
326 print '-'*70
327 print "opened :", sys.argv[1], " as 'file'"
328 print
329 print '-'*70
330 print 'type file.show() to look at its contents'
331 print "type file.register( columnname ) or file.register('all') in order to register columns"
332 print
333 print " due column-registration you declare, that you would like to retrieve the contents of one of the columns"
334 print " after column-registration, the 'file' has new member variables, they are named like the columns"
335 print " PLEASE NOTE: immediatly after registration, the members exist, but they are empty."
336 print " the values are assigned only, when you call file.next() or when you loop over the 'file'"
337 print
338 print "in order to loop over it, just go like this:"
339 print "for row in file:"
340 print " print row.columnname_one, row.columnname_two"
341 print
342 print ""
343 print '-'*70
344
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