On Monday, October 6, 2014 10:52:40 PM UTC+5:30, Dave Angel wrote: > varun7rs Wrote in message: > > On Monday, 6 October 2014 15:03:44 UTC+2, Varun wrote:
> (Deleted all the 8-space quoting. Either use a better email client > or remove the extra 7 lines between every line you > quote.) > >> Okay, I forgot to explain them. L is a set of links, dist is a number > >> (distance), bd is the bandwidth and hc is a number as well > >> (hopcount)...different bandwidths, hopcounts and distances for different > >> links... > >> b(i,x) is what i intend to calculate out of these details...here 'i' could > >> be the head or tail of the link l and x is a node that hosts i > > Unbelievable. I again forgot to express them > > L = [(1,3), (5,7), .....] > > bd = [23, 34,43.44.....] > > dist = [3,7,5,7, ....] > > hc = [2,3,4,1,2,2,...] > > for every l belonging to L, i could be either 1 or 3 for L[0], similarly > > for L[1] it could be 5 or 7 > Now it's clear I don't have a clue. L is either a set or a list. > Little l is an element of that set, and is either a tuple or is > mysteriously subscripted by a boolean at the other end of the > expression. .. As Dave says there are too many loose ends in your spec to make much sense. Anyway heres a small start to help you start off -- both for cleaning up your spec as well as moving towards an implementation Take your denominator term: Σ(l∈L) l You also say "i could be head or tail of l" Dunno what to make of that 'or'... Toss a coin and choose?? So here are two version that will calculate the denominator for head and for tail >>> L = [(1,3), (5,7)] >>> sum(x for (x,y) in L) 6 >>> sum(y for (x,y) in L) 10 If you need to examine the sub-expressions (always a good idea!), use >>> (x for (x,y) in L) <generator object <genexpr> at 0x7fe04025c730> Whazzat? >>> list(x for (x,y) in L) [1, 5] Or just simply >>> [x for (x,y) in L] [1, 5] You can use that literally in the sum >>> sum([x for (x,y) in L]) 6 >>> sum([(x,y) for (x,y) in L]) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for +: 'int' and 'tuple' Python just expressing that you are goofing off by trying to add tuples rather than numbers >>> sum([l for l in L]) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for +: 'int' and 'tuple' Same as above -- https://mail.python.org/mailman/listinfo/python-list
