diff --git a/autolib.py b/autolib.py
index b4df145..c620344 100644
--- a/autolib.py
+++ b/autolib.py
@@ -19,7 +19,8 @@
 # the whole pypy projet is under MIT licence
 # ____________________________________________________________
 "enables us to carry out a calculation and return an option's value"
-from tiramisu.error import DisabledOptionError, SpecialOwnersError
+from tiramisu.error import DisabledOptionError, SpecialOwnersError, ConfigError
+from creole import eosfunc
 # ____________________________________________________________
 # automatic Option object
 special_owners = ['auto', 'fill']
@@ -30,8 +31,6 @@ def special_owner_factory(name, owner, value,
     # we have to carry out a calculation
     return calc_factory(name, callback, callback_params, config)
 
-#g = globals()
-
 def calc_factory(name, callback, callback_params, config):
     # FIXME we have to know the exact status of the config 
     # not to disrupt it
@@ -39,25 +38,50 @@ def calc_factory(name, callback, callback_params, config):
     if callback_params is None:
         callback_params = {}
     tcparams = {}
+    one_is_multi = False
+    len_multi = 0
     for key, value in callback_params.items():
         if type(value) == tuple:
             path, check_disabled = value
             try:
                 opt_value = getattr(config, path)
+                opt = config.unwrap_from_path(path)
             except DisabledOptionError, e:
                 if chek_disabled:
                     continue
                 raise DisabledOptionError(e)
-            tcparams[key] = opt_value
+            is_multi = opt.is_multi()
+            if is_multi:
+                len_value = len(opt_value)
+                if len_multi != 0 and len_multi != len_value:
+                    raise ConfigError('unable to carry out a calculation, '
+                    'option values with multi types must have same length for: '
+                     + name)
+                len_multi = len_value
+                one_is_multi = True
+            tcparams[key] = (opt_value, is_multi)
         else:
-            tcparams[key] = value
+            tcparams[key] = (value, False)
+
+    if one_is_multi:
+        ret = []
+        for incr in range(len_multi):
+            tcp = {}
+            for key, couple in tcparams.items():
+                value, ismulti = couple
+                if ismulti:
+                    tcp[key] = value[incr]
+                else:
+                    tcp[key] = value
+            ret.append(calculate(callback, tcp))
+        return ret
+    else:
+        return calculate(callback, tcparams)
+    
+def calculate(callback, tcparams):
     try:
-        #return getattr(autolib, callback)(name, config)
-        #return g[callback](name, config, **callback_params)
-        from creole import eosfunc
         return getattr(eosfunc, callback)(**tcparams) 
     except AttributeError:
-        import traceback
-        traceback.print_exc()
         raise SpecialOwnersError("callback: {0} not found for "
                                            "option: {1}".format(callback, name))
+