Some documentation of about the dve2 interface.

* iface/dve2/README: New file.
* NEWS: Mention it.
* THANKS: Add Michael Weber.

ChangeLog

+2011-03-07  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Some documentation of about the dve2 interface.
+
+	* iface/dve2/README: New file.
+	* NEWS: Mention it.
+	* THANKS: Add Michael Weber.
+
 2011-03-06  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	* iface/dve2/dve2.cc, iface/dve2/dve2check.cc: Cosmetic changes

NEWS

 New in spot 0.7.1a:
 
-  Nothing yet.
+  * Spot can read DiVinE models.  See iface/dve2/README for details.
 
 New in spot 0.7.1 (2001-02-07):
 

iface/dve2/README

+This directory contains an interface that presents DiVinE models as
+kripke* objects for Spot.
+
+The DiVinE model checker [http://anna.fi.muni.cz/divine/] has a
+specification language called DVE that makes it easy to model
+processes synchonizing through channels
+[http://anna.fi.muni.cz/divine/language.html].
+
+A lot of models can be found in the BEEM database at
+http://anna.fi.muni.cz/models/
+
+For efficient generation of the state space of the model, DiVinE
+compiles the DVE input into a dynamic library that contains anything
+needed to generate the state-space.
+
+The LTSmin people [http://fmt.cs.utwente.nl/tools/ltsmin/] have made a
+patched version of DiVinE that compiles a dynamic library with a very
+simple C interface (no C++) and extra information about state
+variables (name, type, possible values).  We are using this interface,
+therefore you need to install their version of DiVinE in order to use
+Spot's DVE interface.
+
+
+
+Installation of DiVinE
+======================
+
+Use the following commands to compile and install the patched version
+of DiVinE.
+
+  git clone http://fmt.cs.utwente.nl/tools/scm/divine2.git
+  cd divine2
+  mkdir _build && cd _build
+  cmake .. -DMURPHI=OFF -DHOARD=OFF -DGUI=OFF -DRX_PATH= -DCMAKE_INSTALL_PREFIX=$HOME/usr
+  make
+  make install
+
+The CMAKE_INSTALL_PREFIX variable is the equivalent of the --prefix
+option of configure scripts.  If you decide to install in $HOME/usr
+like I do, make sure that $HOME/usr/bin is in your PATH.  If you omit
+the CMAKE_INSTALL_PREFIX setting, it will default to /usr/local.
+
+After installation, you can check that compilation works by running
+the following command on any DVE model.  It should create a file
+model.dve2C (which is a dynamic library).
+
+  divine compile --ltsmin model.dve
+
+
+Usage with Spot
+===============
+
+  The function load_dve2() defined in dve2.hh in this directory
+  will accept "model.dve" or "model.dve2C" as file argument.
+  In the former case, it will call "divine compile --ltsmin"
+  if "model.dve2C" does not exist or is older.  Then load
+  "model.dve2C" dynamically.
+
+  load_dve2() also requires a set of atomic propositions that should
+  be observed in the model.  These are usually the atomic propositions
+  that occur in the formula to verify, but it might be a larger set.
+
+  There are two kinds of atomic propositions, those that refer to the
+  state of a process, and those that compare the value of a variable.
+  Let's have some example on an excerpt of the beem-peterson.4.dve
+  model included in this directory:
+
+    byte pos[4];
+    byte step[4];
+
+    process P_0 {
+    byte j=0, k=0;
+    state NCS, CS, wait ,q2,q3;
+    init NCS;
+    trans
+     NCS -> wait { effect j = 1; },
+     wait -> q2  { guard j < 4; effect pos[0] = j;},
+     q2 -> q3 { effect step[j-1] = 0, k = 0; },
+     q3 -> q3 { guard k < 4 && (k == 0 || pos[k] < j); effect k = k+1;},
+     q3 -> wait { guard step[j-1] != 0 || k == 4; effect j = j+1;},
+     wait -> CS { guard j == 4; },
+     CS -> NCS { effect pos[0] = 0;};
+    }
+
+  The following atomic propositions could be used in LTL formula:
+
+    P_0.CS          Process P_0 is in state CS.
+    "pos[3] < 3"    Global variable pos[3] is less than 3.
+    "P_0.j >= 2"    Process P_0's variable j is greater or equal to 2.
+    P_0.j           This is equivalent to "P_0.j != 0".
+
+  Comparisons operators available are "<", ">", ">=", "<=", "==", and
+  "!=".  The left operant should always be a variable and the right
+  operand should always be a number, so you cannot write something
+  like "P_0.j <= P_0.i".
+
+  Because the LTL parser knows nothing about the details of the
+  languages we interface with, every atomic proposition that cannot be
+  express using only alphanumeric characters (plus `_' and `.') should
+  be enclosed in double quote.
+
+  Caveat: "P_0.j >= 2" and " P_0.j>=2" (watch the spaces!) are
+  considered to be two atomic propositions with the same semantics.
+
+Examples
+========
+
+  Using the dve2check program built into this directory, we can verify
+  that the critical section is accessed infinitely often by some
+  processes using:
+
+    % ./dve2check beem-peterson.4.dve '!GF(P_0.CS|P_1.CS|P_2.CS|P_3.CS)'
+    2239039 unique states visited
+    0 strongly connected components in search stack
+    11449204 transitions explored
+    1024245 items max in DFS search stack
+    no accepting run found
+
+  Process P_0 can starve, waiting to enter in critical section:
+
+     % ./dve2check beem-peterson.4.dve '!G(P_0.wait -> F P_0.CS)'
+     2190 unique states visited
+     34 strongly connected components in search stack
+     4896 transitions explored
+     83 items max in DFS search stack
+     an accepting run exists (use -C to print it)
+
+   Variable pos[1] is not always < 3 (this formula makes no sense, it
+   is just to demonstrate the use of double quote).
+
+     % ./dve2check beem-peterson.4.dve '!G("pos[1] < 3")'
+     130 unique states visited
+     61 strongly connected components in search stack
+     132 transitions explored
+     130 items max in DFS search stack
+     an accepting run exists (use -C to print it)