[cl-graph-devel] Problem with find-connected-components

[Gary King]

Hi Daniel,

What you're doing looks to me like it should work. I'll take a look  
this weekend and see what's gone wrong.

On Sep 8, 2007, at 4:18 PM, Daniel Katz wrote:

> Hi -
>
> I'm trying out cl-graph, and got as far as creating a simple graph  
> but got stopped when I tried to find it's connected components.  In  
> particular, I tried to build the following graph and get a list of  
> the connected subgraphs as follows:
>
> ---------------------------------------------------------------------- 
> --------------------------------------
> (defun foo ()
>   (let ((graph (cl-graph:make-graph 'cl-graph:graph-container)))
>     (cl-graph:add-vertex graph "a")
>     (cl-graph:add-vertex graph "b")
>     (cl-graph:add-vertex graph "c")
>     (cl-graph:add-vertex graph "d")
>     (cl-graph:add-vertex graph "e")
>     (cl-graph:add-edge-between-vertexes graph "a" "b" :edge- 
> type :directed)
>     (cl-graph:add-edge-between-vertexes graph "b" "c" :edge- 
> type :directed)
>     (cl-graph:add-edge-between-vertexes graph "c" "a" :edge- 
> type :directed)
>     (cl-graph:add-edge-between-vertexes graph "d" "e" :edge- 
> type :directed)
>     (cl-graph:find-connected-components graph)))
> ---------------------------------------------------------------------- 
> ------------------------------------
>
> which I would expect to return a list of two subgraphs (one for a-b- 
> c component and one for d-e component).   Instead, I ended up in  
> the debugger as follows:
>
> ---------------------------------------------------------------------- 
> -----------------------------------
> > (foo)
>
> keyword argument not a symbol: 536870911.
>    [Condition of type SB-INT:SIMPLE-PROGRAM-ERROR]
>
> Restarts:
> 0: [ABORT] Return to SLIME's top level.
> 1: [ABORT] Exit debugger, returning to top level.
>
> Backtrace:
>   0: (SB-PCL::CHECK-APPLICABLE-KEYWORDS 0 (:NEW-GRAPH :DEPTH)  
> 8397616 1)
>   1: ((LAMBDA
>           (SB-PCL::.PV-CELL. SB-PCL::.NEXT-METHOD-CALL.
>            #1="#<...>" . #1#))
>       #<unused argument>
>       #<unused argument>
>       #<CL-GRAPH:GRAPH-CONTAINER [5,4] {1261BFC9}>
>       #<b>
>       8397616
>       1)
>   2: ((LAMBDA (METABANG.CL-CONTAINERS::ITEM)) #<UFN: #<b>, 1  
> {126266B9}>)
>   3: ((SB-PCL::FAST-METHOD METABANG.CL-CONTAINERS:ITERATE-FORWARD
>        (METABANG.CL-CONTAINERS::BASIC-ITERATOR T))
>       #<unavailable argument>
>       #<unavailable argument>
>       #<CHAINS-TEST::UNIQUE-VALUE-ITERATOR-MIXIN-AND-TRANSFORMING- 
> ITERATOR-MIXIN-AND-HASH-TABLE-ITERATOR T {126279D9}>
>       #<CLOSURE (LAMBDA #) {126287A5}>)
>   4: (METABANG.CL-CONTAINERS::COLLECTOR-INTERNAL
>       #<CHAINS-TEST::UNIQUE-VALUE-ITERATOR-MIXIN-AND-TRANSFORMING- 
> ITERATOR-MIXIN-AND-HASH-TABLE-ITERATOR T {126279D9}>
>       #<STANDARD-GENERIC-FUNCTION METABANG.CL-CONTAINERS:ITERATE- 
> ELEMENTS (10)>
>       NIL
>       #<CLOSURE (LAMBDA #) {1262878D}>)
>   5: (SB-INT:SIMPLE-EVAL-IN-LEXENV (FOO) #<NULL-LEXENV>)
> ---------------------------------------------------------------------- 
> ---------------------------
>
> Clearly the number 536870911 is just MOST-POSITIVE-FIXNUM (I'm  
> running sbcl 1.0.7 on Mac OS X)
>
> ---------------------------------------------------------------------- 
> ---------------------------
> > most-positive-fixnum
> 536870911
> ---------------------------------------------------------------------- 
> --------------------------
>
> which is used in the code for find-connected-components, but before  
> I start digging into that code, I thought I'd ask here if I was  
> doing something stupid first.
>
>
> So:  should the function foo I defined above work?  And if so, what  
> should I be expecting it to return?
>
>
> Thanks!
>
> Dan
>
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--
Gary Warren King, metabang.com
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