I understand the material in the chapter. However, the exercises are
completely confusing to me. Therefore, a discussion of the chapter may
clarify. For the 8-puzzle problem, I am not able to understand the
existence of two disjoint sets of all possible states in which a state
from one set can't transform to a state in the other set by any number
of moves. I would assume any state can be reached by in other state. In
other words, there are situations (initial state - goal configuration)
in which the puzzle isn't solvable? Does the two disjoint sets exit
because the problem becomes an NP-Complete problem for those states
trying to reach the states in the other disjoint set. And, the 9!/2
calculation for all possible states derives from this theorem of
exactly half of the possible states transform into a given goal, is
this true?

--- In aima-talk@yahoogroups.com, ramanathan pl <ramkrshn36@...>
wrote:
>
> Hi,
>
> When I was going through the 8 puzzle example in fig. 3.4 of AIMA
2nd edition, I found that from the given start state (7 2 4 5 0 6 8 3
1), it is NOT possible to reach the given Goal state ( 0 1 2 3 4 5 6
7 8) since both the states belong to two disjoint sets and it is not
possible to transform from a state in one set to a state in another
set , immaterial of how many moves we make.
>
> Any similar comments and discussions appreciated.
>
> Thanks
> Ram
>
>
>
>
>
It's evident two disjoint sets of all possible states for the 8-
puzzle problem exist. However, I don't understand. I would assume it
is possible to reach any state from a given state. What are the
differences between the two disjoint sets? I am seriously confused.
______________________________________________________________________
_________
> Be a better friend, newshound, and
> know-it-all with Yahoo! Mobile.  Try it now.
http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
>

--- In aima-talk@yahoogroups.com, "kiana" <blacksilk79@...> wrote:
>
> I understand the material in the chapter. However, the exercises
are
> completely confusing to me. Therefore, a discussion of the chapter
may
> clarify. For the 8-puzzle problem, I am not able to understand the
> existence of two disjoint sets of all possible states in which a
state
> from one set can't transform to a state in the other set by any
number
> of moves. I would assume any state can be reached by in other
state. In
> other words, there are situations (initial state - goal
configuration)
> in which the puzzle isn't solvable? Does the two disjoint sets exit
> because the problem becomes an NP-Complete problem for those states
> trying to reach the states in the other disjoint set. And, the 9!/2
> calculation for all possible states derives from this theorem of
> exactly half of the possible states transform into a given goal, is
> this true?
>
I'm confused, any clarification is greatly appreciated.

--- In aima-talk@yahoogroups.com, "kiana" <blacksilk79@...> wrote:
>
> I understand the material in the chapter. However, the exercises
are
> completely confusing to me. Therefore, a discussion of the chapter
may
> clarify. For the 8-puzzle problem, I am not able to understand the
> existence of two disjoint sets of all possible states in which a
state
> from one set can't transform to a state in the other set by any
number
> of moves. I would assume any state can be reached by in other
state. In
> other words, there are situations (initial state - goal
configuration)
> in which the puzzle isn't solvable? Does the two disjoint sets exit
> because the problem becomes an NP-Complete problem for those states
> trying to reach the states in the other disjoint set. And, the 9!/2
> calculation for all possible states derives from this theorem of
> exactly half of the possible states transform into a given goal, is
> this true?
>
Discussions of the topics in the book leads to a better understanding
of the material. I need clarification of the topics in order to
answer the exercies, not necessarily the answer to the questions. In
order for me to understand the material further, I need to understand
the questions. The existence of the disjoint sets were discussed in
book, so I would like to elaborate on that topic. I don't understand
that section of the book. Thank you.

I'm looking to create a test file and successor function for BFS in
the AIMA code. However, in order to instantiate a BFS I have to pass
in a QueueSearch. I ran into the problem when trying to instantiate
the QueueSearch. I know that QueueSearch extends the NodeExpander but
I've tried several ways to instantiate it and I keep getting
complaints from eclipse. Does anyone know how to create a QueueSearch
so that eclipse doesn't complain?

Thank you for your time.

The code for QueueSearch begins as follows

"public abstract class QueueSearch  .... "

The "abstract" keyword implies you cannot instantiate the class. You
need to instantiate one of its concrete subclasses (TreeSearch or
GraphSearch).

The demo and unit test classes have a dozen plus examples of how these
may be instantiated. The readme file explains the two hierarchies of
search and how they relate to each other.

"> I've tried several ways to instantiate it and I keep getting
> complaints from eclipse."

When this happens the next time, do try to understand what the error
message is trying to communicate. An attempt at doing this would have
exposed the "trying to instantiate an abstract class" error.

In other words, eclipse complains for a reason!



--- In aima-talk@yahoogroups.com, "inyourmind6684" <dtamayo@...> wrote:
>
> I'm looking to create a test file and successor function for BFS in
> the AIMA code. However, in order to instantiate a BFS I have to pass
> in a QueueSearch. I ran into the problem when trying to instantiate
> the QueueSearch. I know that QueueSearch extends the NodeExpander but
> I've tried several ways to instantiate it and I keep getting
> complaints from eclipse. Does anyone know how to create a QueueSearch
> so that eclipse doesn't complain?
>
> Thank you for your time.
>

--- In aima-talk@yahoogroups.com, "inyourmind6684" <dtamayo@...> wrote:
>
> I'm looking to create a test file and successor function for BFS in
> the AIMA code. However, in order to instantiate a BFS I have to pass
> in a QueueSearch. I ran into the problem when trying to instantiate
> the QueueSearch. I know that QueueSearch extends the NodeExpander but
> I've tried several ways to instantiate it and I keep getting
> complaints from eclipse. Does anyone know how to create a QueueSearch
> so that eclipse doesn't complain?
>
> Thank you for your time.
>
Do we use the AIMA code examples, i.e. BFS and QueueSearch, for the
exercises in the book? Or, are we supposed to define and implement all
of the code for the exercises ourselves?

The attachment was stripped as suspected, so here's the readable version...

http://ai.autonomy.net.au/chrome/site/AIMA-18.4.png

Nima

--- In aima-talk@yahoogroups.com, "Nima Talebi" <nima.talebi@...> wrote:
>
> Okay, I can already see a flaw in this, here's my revised version...
>
> I've attached my formula as a png, hope it gets through, in case it
> doesn't...
>
> *Text:*
> E=|_sum_{{i=0};{i=M-m};{|_pmatrix1x2_{{M};{m+i}}ε^{m+i}}}
>
> *LaTeX:
> *\mbox{E}=\sum_{i=0}^{i=M-m}{\left(\begin{array}{c} M \\ m+i
> \end{array}\right)\epsilon ^{m+i}}
>
> ...where m is the *bigger half* - that is the `half' that has just enough
> power to out-weight the other half, for example where M = 20, m = 11, where
> M = 5, m = 3.
>
> Again, I don't think I have the right, or at least most elegant solution to
> the problem, I feel it has to be much simpler - otherwise the question
> wouldn't seriously expect us to calculate the above formula for M = 20 as
> that sum would expand into 9 terms!
>
> Nima
>
>
> On Fri, Oct 24, 2008 at 12:37 AM, Nima Talebi <nima.talebi@...> wrote:
>
> > Hi,
> >
> > I'm interested to see if my solution is even remotely correct, the question
> > is to derive the error formula given the number of experts/hypotheses (M)
> > and also the error of each hypotheses (e) - assuming all to be the same, and
> > that all are independent of one another...
> >
> > I treated this as a probability problem (and unsure if I should have done
> > so), and hence derived a formula which yields the following results...
> >
> > M:5, e:0.10, 0.0100
> > M:5, e:0.20, 0.0800
> > M:5, e:0.40, 0.6400
> > M:10, e:0.10, 0.0002
> > M:10, e:0.20, 0.0134
> > M:10, e:0.40, 0.8602
> > M:20, e:0.10, 0.0000
> > M:20, e:0.20, 0.0034
> > M:20, e:0.40, 7.0448
> >
> > The third column is the total error for the network I calculated; it
> > certainly looks wrong from looking at the last value, but I'd like to know
> > how to go about solving this as it's rather intriguing.
> >
> > My `formula' in Python form is as follows...
> >
> > def fact(k):
> >   return reduce(lambda i, j : i*j, range(1, k+1))
> >
> > for M in 5, 10, 20:
> >   for e in 0.1, 0.2, 0.4:
> >     m  = M/2+1
> >     _m = M-m
> >
> >     print "M:%d, e:%0.2f, %0.4f"%(M, e, (fact(M) * pow(e, m))/(fact(_m) *
> > fact(m)))
> >
> > Thanks to anyone who has a crack at solving this =)
> >
> > Nima
> >
> >
>
>
> --
> Nima Talebiw: http://ai.autonomy.net.au/
> p: +61-4-0667-7607  m: nima@...
>

Iam interested in AI .I need guidelines to solve the exercises in the
book"Artificial intelligence A modern approach".

--- In aima-talk@yahoogroups.com, "sprgr77" <sprgr77@...> wrote:
>
> Iam interested in AI .I need guidelines to solve the exercises in the
> book"Artificial intelligence A modern approach".
>

...and your question would be... ?

hi
I was looking at AIMA python code repository in google and asking
myself is python still considered viable in this community. the java
repository seems to have all the recent focus and development. why?
personal preferences of project owners or some other reasons?


Best Regards
Mani

Hi,

I wouldn't want to speak for the maintainers  of the python
repository, but as the maintainer of the java code repository I think
it is important to understand how open source works.

The amount of progress is directly dependent on how much free time and
energy the maintainers have and often this has peaks and lulls. I
wrote most of the java code for AIMA, but I have been insanely busy
over the last year. Dr Ciaran O'Reilly has been adding a *lot* of
code, however, mostly in the logic section, but also filling in some
of the gaps in search.(see the svn branch dedicated to this effort.
This will be merged into  a new release soon).

Next year, (2009) I'll have more free time and I plan to add graphics
to the existing codebase. Particularly for small projects with
contributors in the single digits, this ebb and flow is just how it works.

If you believe that Python makes a good implementation language (I
think it does - the size of the python implementation of an algorithm
is a fraction of the size of the equivalent java code), please
contribute some code. That way, everyone wins.

My 2 cents,

Ravi


--- In aima-talk@yahoogroups.com, "Mani Sabri" <mani_sabri@...> wrote:
>
> hi
> I was looking at AIMA python code repository in google and asking
> myself is python still considered viable in this community. the java
> repository seems to have all the recent focus and development. why?
> personal preferences of project owners or some other reasons?
>
>
> Best Regards
> Mani
>

The formulation in Fig 3.1 is not mentioned again, so its application
to the clear examples in Sec 3.2 is obscure at best.

How *does* it apply? Esp. since it only returns a single action.

    -- Bob Futrelle

Newton Mass &
Northeastern University
Sent from my iPhone

Hi all!

I'm new in AI and I cannot understand this algorithm. Can anybody give me a
help?

Thanks in advance!

Victor

We're having a contest to design the cover for the 3rd edition.

Open to instructors and students, see the contest rules at
http://media.pearsoncmg.com/ph/esm/ecs_ai/ .  Deadline June 15th.

-Peter Norvig

That's great. Is there any information available on what to expect in
the 3rd edition or an estimate of when to expect it to be available
for purchase?

   Thanks

     Donnchadh

2009/4/22 Peter Norvig <peter@...>:
>
>
> We're having a contest to design the cover for the 3rd edition.
>
> Open to instructors and students, see the contest rules at
> http://media.pearsoncmg.com/ph/esm/ecs_ai/ . Deadline June 15th.
>
> -Peter Norvig
>

Light-hearted suggestion:

Instead of God's finger touching Adam, ala Michelangelo, we could have a
human in the clouds touching the finger of a robot agent.


  - Bob Futrelle



On 12:51:03 am 04/22/09 "Peter Norvig" <peter@...> wrote:
>
>
>
>             We're having a contest to design the cover for the 3rd
> edition.
> Open to instructors and students, see the contest rules at
> http://media.pearsoncmg.com/ph/esm/ecs_ai/ .  Deadline June 15th.
> -Peter Norvig
>
>
>
>

If it were up to me, I would have it open to anyone, regardless of residency,
and regardless of status as a student or teacher.  But Prentice Hall has legal
issues they have to work with, and that's what they decided would be easiest.

-Peter

--- In aima-talk@yahoogroups.com, Bilal Hayat Butt <bilal_hayat_butt@...> wrote:
>
> Whats the point in having it for US residents only?
> ---------------
> 2.  Eligibility.
>
> Open to legal U.S. residents, that are instructors or students (enrolled at a
two- or four-year college).
>
> [3 ! |_ /

Hi!

I found several issues with the code in csp.py, version
aima-python.2007.06.15.zip:

1) Forward Checking and Maintain Arc Consistency don't work because of a thinko
in csp.unassign:

def unassign(self, var, assignment):
     """Remove {var: val} from assignment; that is backtrack. (...) """
     if var in assignment:
         # Reset the curr_domain to be the full original domain
         if self.curr_domains:
-->         self.curr_domains[var] = self.domains[var][:]
         del assignment[var]

That cannot work because it discards too much information. The assignments made
in previous recursions can all potentially lead to prunings of the current
node's domain. In the highlighted line, instead of carefully undoing of the
effects a particular assignment, the domain is reset to its initial value,
thereby throwing away knowledge of those earlier prunings.

Both backtrackging_search(usa, fc=True) and backtracking_search(usa, mac=True)
return incorrectly colored maps.

2) The Most Constrained Variable heuristic has it backwards and prefers less
constrained variables over more constrained variables. That's why
backtracking_search(usa, mcv=True) is guaranteed to run for many hours,
exploring the search tree in the most inefficient possible way.

3) The Least Constraining Value heuristic fails to compile on modern python.

I took the liberty of developing and testing a patch for the aforementioned
issues. Furthermore, it contains a formulation of the Sudoku problem using the
csp.py machinery.

Please find it at:
http://code.google.com/p/aima-python/issues/detail?id=11

regards,
Edgar Holleis

Simple question: How about Mathemaitca for this purpose?

I've been using Lisp, C, Java and now using Mathematica.

--- In aima-talk@yahoogroups.com, "matsudayuko69" <matsuda.yuko@...> wrote:
>
> Simple question: How about Mathemaitca for this purpose?
>
> I've been using Lisp, C, Java and now using Mathematica.
>

I'd be happy to contribute in developing Mathematica code for AIMA.

Regards,

Juan Flores

The number of states for the first incremental formulation is stated to
be 64 . 63 . ... . 57.
As far as it's the "number of sequences", there is no problem, but it is
confused with "state space size" in the next paragraphs, while this
doesn't take into account the the arrangements with less than 8 queens
(1, 2, ..., 7) and also the fact that most of the states are repeated.
So, I'm guessing that the state space size should be:

64/1! + (64 . 63)/2! + ... + (64 . 63 . ... . 57)/8!