mirror of
https://github.com/triqs/dft_tools
synced 2024-12-27 23:03:51 +01:00
188 lines
6.7 KiB
Python
188 lines
6.7 KiB
Python
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################################################################################
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#
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# TRIQS: a Toolbox for Research in Interacting Quantum Systems
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#
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# Copyright (C) 2011 by M. Ferrero, O. Parcollet
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#
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# TRIQS is free software: you can redistribute it and/or modify it under the
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# terms of the GNU General Public License as published by the Free Software
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# Foundation, either version 3 of the License, or (at your option) any later
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# version.
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#
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# TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# TRIQS. If not, see <http://www.gnu.org/licenses/>.
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#
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################################################################################
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__all__ = ['LazyExpr', 'LazyExprTerminal', 'eval_expr_with_context', 'lazy', 'lazy_function', 'transform', 'eval_expr']
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class __aux(object):
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def __add__(self, y): return LazyExpr("+", LazyExpr(self), LazyExpr(y))
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def __sub__(self, y): return LazyExpr("-", LazyExpr(self), LazyExpr(y))
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def __mul__(self, y): return LazyExpr("*", LazyExpr(self), LazyExpr(y))
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def __div__(self, y): return LazyExpr("/", LazyExpr(self), LazyExpr(y))
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def __radd__(self, y): return LazyExpr("+", LazyExpr(y), LazyExpr(self))
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def __rsub__(self, y): return LazyExpr("-", LazyExpr(y), LazyExpr(self))
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def __rmul__(self, y): return LazyExpr("*", LazyExpr(y), LazyExpr(self))
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def __rdiv__(self, y): return LazyExpr("/", LazyExpr(y), LazyExpr(self))
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def __iadd__(self, y): return self.set_from(self+y)
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def __isub__(self, y): return self.set_from(self-y)
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def __imul__(self, y): return self.set_from(self*y)
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def __idiv__(self, y): return self.set_from(self/y)
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def __call__(self, *args): return LazyExpr("F", make_lazy(self), *map(make_lazy, args))
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class LazyExprTerminal (__aux):
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pass
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class LazyExpr (__aux):
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"""
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"""
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def __init__ (self, *args):
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if len(args) == 1:
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a0 = args[0]
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self.tag, self.childs = (a0.tag, a0.childs) if isinstance(a0, self.__class__) else ("T", [a0])
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elif len(args) >1:
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self.tag, self.childs = args[0], args[1:]
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else: raise ValueError, "too few arguments"
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def copy(self):
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""" Deep copy"""
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return LazyExpr(self.tag, self.childs)
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def set_from(self, y):
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""" self:= y """
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self.tag, self.childs = tmp.tag, tmp.childs
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return self
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def is_terminal(self):
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"""Returns true iif the expression is a terminal """
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return self.tag=="T"
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def get_terminal(self):
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"""Returns the terminal if the expression is a terminal else None """
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return self.childs[0] if self.tag=="T" else None
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def __aux_print(self, F):
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op_priority = {'T': 100, "+": 1 , '-': 1, '*': 2, '/': 2}
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if self.tag == "T": return F(self.childs[0])
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if self.tag == "F":
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return reduce (lambda s, e: s+ F(e), self.childs[1:], self.childs[0].get_terminal()[0] + "(" ) + ')'
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par = lambda op, e: "%s"%e if op_priority[e.tag] >= op_priority[op] else "(%s)"%e
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return "%s %s %s "%(par(self.tag , self.childs[0]), self.tag , par(self.tag , self.childs[1]))
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def __str__(self): return self.__aux_print(str)
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def __repr__(self): return self.__aux_print(repr)
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#def __call__ (self, *args, **kwargs):
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#-----------------------------------------------------
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def eval_expr_with_context(eval_term, expr ):
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if expr.tag == "T": return eval_term(expr.childs[0]) #eval the terminals
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if expr.tag == "F":
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f= expr.childs[0].get_terminal()[1]
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return f (*map(lambda e:eval_expr_with_context(eval_term, e) , expr.childs[1:]) )
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# Binary operations:
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ops = { "+": lambda x, y: x + y, "-": lambda x, y: x - y, "*": lambda x, y: x * y, "/": lambda x, y: x / y }
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return ops[expr.tag] (*map(lambda e:eval_expr_with_context(eval_term, e) , expr.childs) )
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#-----------------------------------------------------
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def make_lazy(x): return LazyExpr(x)
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#-----------------------------------------------------
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def lazy_function(name, F):
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return LazyExpr("T", (name, F))
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#-----------------------------------------------------
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def transform (expr, Fnode, Fterm = lambda x: x ):
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"""Given two functions
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Fnode(tag, childs) -> (tag, childs)
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Fterm(x) -> x'
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it transforms the expression recursively
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"""
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if expr.tag == "T": return LazyExpr("T", Fterm(expr.childs[0]))
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tag, ch = Fnode (expr.tag, map(lambda e: transform (e, Fnode), expr.childs))
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ch = map(lambda x: LazyExpr(x), ch)
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return LazyExpr (tag, *ch)
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#-----------------------------------------------------
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def all_terminals (expr):
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"""Generate all terminals of an expression"""
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if expr.tag == "T":
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yield expr.childs[0]
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else:
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for ch in expr.childs:
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for t in all_terminals(ch):
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yield t
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def eval_expr (expr):
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#def eval_expr_or_pass (expr):
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"""
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If expr is not a LazyExpr: returns expr unchanged.
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Otherwise, tries to eval it by looking for some element in the tree that can create the evaluation context and is not purely abstract
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"""
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if not isinstance (expr, LazyExpr): return expr # do nothing
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# first take all terminals
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C = [ t.__lazy_expr_eval_context__() for t in all_terminals(expr) if hasattr(t, "__lazy_expr_eval_context__") ]
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if C == []: raise ValueError, "Evaluation impossible: expression is purely abstract"
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all_equal = reduce (lambda x, y: x and y , [ C[0] == x for x in C ])
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if not all_equal: raise ValueError, "Evaluation impossible: various terminals lead to incompatible evaluation contexts: their type are not compatible for binary ops"
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C = C[0]
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return eval_expr_with_context(C, expr)
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#--------------- TEST --------------------------------------
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if __name__ == "__main__":
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class T (LazyExprTerminal):
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def __init__(self, n): self.name = n
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def __repr__(self): return self.name
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g1, g2 = T("g1"), T("g2")
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a = 2 * g1 + g2/3 + 5
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print a
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def e_t(x):
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d = { "g1": 10, "g2": 100}
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return d[x.name] if isinstance(x, T) else x
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assert eval_expr_with_context(e_t, a) ==58
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def find_sca(tag, childs):
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if tag =="+":
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t = childs[1].get_terminal()
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if t: childs[1] = T("$$" + str(childs[1]))
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return (tag, childs)
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b= transform(a, find_sca)
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print b
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# a lazy function:
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def f (x): return -x
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fa = lazy_function("f", f) (a)
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print fa, eval_expr_with_context(e_t, fa)
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assert eval_expr_with_context(e_t, fa) == f(eval_expr_with_context(e_t, a) )
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