Chris@87: #!/usr/bin/env python
Chris@87: """Prints type-coercion tables for the built-in NumPy types
Chris@87: 
Chris@87: """
Chris@87: from __future__ import division, absolute_import, print_function
Chris@87: 
Chris@87: import numpy as np
Chris@87: 
Chris@87: # Generic object that can be added, but doesn't do anything else
Chris@87: class GenericObject(object):
Chris@87:     def __init__(self, v):
Chris@87:         self.v = v
Chris@87: 
Chris@87:     def __add__(self, other):
Chris@87:         return self
Chris@87: 
Chris@87:     def __radd__(self, other):
Chris@87:         return self
Chris@87: 
Chris@87:     dtype = np.dtype('O')
Chris@87: 
Chris@87: def print_cancast_table(ntypes):
Chris@87:     print('X', end=' ')
Chris@87:     for char in ntypes: print(char, end=' ')
Chris@87:     print()
Chris@87:     for row in ntypes:
Chris@87:         print(row, end=' ')
Chris@87:         for col in ntypes:
Chris@87:             print(int(np.can_cast(row, col)), end=' ')
Chris@87:         print()
Chris@87: 
Chris@87: def print_coercion_table(ntypes, inputfirstvalue, inputsecondvalue, firstarray, use_promote_types=False):
Chris@87:     print('+', end=' ')
Chris@87:     for char in ntypes: print(char, end=' ')
Chris@87:     print()
Chris@87:     for row in ntypes:
Chris@87:         if row == 'O':
Chris@87:             rowtype = GenericObject
Chris@87:         else:
Chris@87:             rowtype = np.obj2sctype(row)
Chris@87: 
Chris@87:         print(row, end=' ')
Chris@87:         for col in ntypes:
Chris@87:             if col == 'O':
Chris@87:                 coltype = GenericObject
Chris@87:             else:
Chris@87:                 coltype = np.obj2sctype(col)
Chris@87:             try:
Chris@87:                 if firstarray:
Chris@87:                     rowvalue = np.array([rowtype(inputfirstvalue)], dtype=rowtype)
Chris@87:                 else:
Chris@87:                     rowvalue = rowtype(inputfirstvalue)
Chris@87:                 colvalue = coltype(inputsecondvalue)
Chris@87:                 if use_promote_types:
Chris@87:                     char = np.promote_types(rowvalue.dtype, colvalue.dtype).char
Chris@87:                 else:
Chris@87:                     value = np.add(rowvalue, colvalue)
Chris@87:                     if isinstance(value, np.ndarray):
Chris@87:                         char = value.dtype.char
Chris@87:                     else:
Chris@87:                         char = np.dtype(type(value)).char
Chris@87:             except ValueError:
Chris@87:                 char = '!'
Chris@87:             except OverflowError:
Chris@87:                 char = '@'
Chris@87:             except TypeError:
Chris@87:                 char = '#'
Chris@87:             print(char, end=' ')
Chris@87:         print()
Chris@87: 
Chris@87: print("can cast")
Chris@87: print_cancast_table(np.typecodes['All'])
Chris@87: print()
Chris@87: print("In these tables, ValueError is '!', OverflowError is '@', TypeError is '#'")
Chris@87: print()
Chris@87: print("scalar + scalar")
Chris@87: print_coercion_table(np.typecodes['All'], 0, 0, False)
Chris@87: print()
Chris@87: print("scalar + neg scalar")
Chris@87: print_coercion_table(np.typecodes['All'], 0, -1, False)
Chris@87: print()
Chris@87: print("array + scalar")
Chris@87: print_coercion_table(np.typecodes['All'], 0, 0, True)
Chris@87: print()
Chris@87: print("array + neg scalar")
Chris@87: print_coercion_table(np.typecodes['All'], 0, -1, True)
Chris@87: print()
Chris@87: print("promote_types")
Chris@87: print_coercion_table(np.typecodes['All'], 0, 0, False, True)