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changeset 11720:550c163c90e0 octave-forge

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Fixed computation of utilization in qncmmva
author mmarzolla
date Thu, 23 May 2013 20:12:57 +0000
parents 0fa62b47e5cb
children af09f99237db
files main/queueing/ChangeLog main/queueing/doc/INSTALL main/queueing/inst/qncmmva.m main/queueing/inst/qncsmva.m
diffstat 4 files changed, 38 insertions(+), 17 deletions(-) [+]
line wrap: on
line diff
--- a/main/queueing/ChangeLog	Tue May 21 20:04:43 2013 +0000
+++ b/main/queueing/ChangeLog	Thu May 23 20:12:57 2013 +0000
@@ -1,3 +1,9 @@
+2013-05-XX Moreno Marzolla <marzolla@cs.unibo.it>
+
+	* Version 1.2.2 released
+	* Fixed bug in qncmmva: utilization for M/M/m centers, m>1, was not correctly scaled to [0,1]
+	* Added warning to qncsmva to inform user about potential loss of accuracy due to load-dependent servers
+
 2013-02-05 Moreno Marzolla <marzolla@cs.unibo.it>
 
 	* Version 1.2.1 released
--- a/main/queueing/doc/INSTALL	Tue May 21 20:04:43 2013 +0000
+++ b/main/queueing/doc/INSTALL	Thu May 23 20:12:57 2013 +0000
@@ -16,7 +16,7 @@
 1.1 Installation through Octave package management system
 =========================================================
 
-The most recent version of `queueing' is 1.2.0 and can be downloaded
+The most recent version of `queueing' is 1.2.1 and can be downloaded
 from Octave-Forge
 
    `http://octave.sourceforge.net/queueing/'
@@ -48,7 +48,7 @@
      Octave-Forge; then, to install the package in the system-wide
      location issue this command at the Octave prompt:
 
-          octave:1> pkg install _queueing-1.2.0.tar.gz_
+          octave:1> pkg install _queueing-1.2.1.tar.gz_
 
      (you may need to start Octave as root in order to allow the
      installation to copy the files to the target locations). After
@@ -57,7 +57,7 @@
 
      If you do not have root access, you can do a local install using:
 
-          octave:1> pkg install -local queueing-1.2.0.tar.gz
+          octave:1> pkg install -local queueing-1.2.1.tar.gz
 
           Note: Octave version 3.2.3 as shipped with Ubuntu 10.04 LTS
           seems to ignore `-local' and always tries to install the
@@ -70,7 +70,7 @@
           octave:1>pkg list queueing
           Package Name  | Version | Installation directory
           --------------+---------+-----------------------
-              queueing  |   1.2.0 | /home/moreno/octave/queueing-1.2.0
+              queueing  |   1.2.1 | /home/moreno/octave/queueing-1.2.1
 
   4. Starting from version 1.1.1, `queueing' is no longer automatically
      loaded on Octave startup. To make the functions available for use,
@@ -94,8 +94,8 @@
 If you want to manually install `queueing' in a custom location, you
 can download the tarball and unpack it somewhere:
 
-     tar xvfz queueing-1.2.0.tar.gz
-     cd queueing-1.2.0/queueing/
+     tar xvfz queueing-1.2.1.tar.gz
+     cd queueing-1.2.1/queueing/
 
    Copy all `.m' files from the `inst/' directory to some target
 location. Then, start Octave with the `-p' option to add the target
--- a/main/queueing/inst/qncmmva.m	Tue May 21 20:04:43 2013 +0000
+++ b/main/queueing/inst/qncmmva.m	Thu May 23 20:12:57 2013 +0000
@@ -133,11 +133,13 @@
 ## @table @var
 ##
 ## @item U
-## If @math{k} is a FCFS, LCFS-PR or PS node, then @code{@var{U}(c,k)}
-## is the class @math{c} utilization at center
-## @math{k}. If @math{k} is an IS node, then @code{@var{U}(c,k)} is the
-## class @math{c} @emph{traffic intensity} at center @math{k},
-## defined as @code{@var{U}(c,k) = @var{X}(c,k)*@var{S}(c,k)}. 
+## If @math{k} is a FCFS, LCFS-PR or PS node (@code{@var{m}(k) @geq{}
+## 1}), then @code{@var{U}(c,k)} is the class @math{c} utilization at
+## center @math{k}, @math{0 @leq{} U(c,k) @leq{} 1}. If @math{k} is an
+## IS node, then @code{@var{U}(c,k)} is the class @math{c} @emph{traffic
+## intensity} at center @math{k}, defined as @code{@var{U}(c,k) =
+## @var{X}(c,k)*@var{S}(c,k)}. In this case the value of
+## #code{@var{U}(c,k)} may be greater than one.
 ##
 ## @item R
 ## @code{@var{R}(c,k)} is the class @math{c} response time at
@@ -427,7 +429,7 @@
     endwhile
     Q = Q_next;
   endfor
-  U = diag(X)*D; # U(c,k) = X(c)*D(c,k)
+  U = diag(X)*D ./ max(1,m); # U(c,k) = X(c)*D(c,k)
   Q = diag(X)*(R.*V);
   X = diag(X)*V;
 endfunction
--- a/main/queueing/inst/qncsmva.m	Tue May 21 20:04:43 2013 +0000
+++ b/main/queueing/inst/qncsmva.m	Thu May 23 20:12:57 2013 +0000
@@ -71,11 +71,12 @@
 ## @table @var
 ##
 ## @item U
-## If @math{k} is a FCFS, LCFS-PR or PS node (@code{@var{m}(k) == 1}),
-## then @code{@var{U}(k)} is the utilization of center @math{k}. If
-## @math{k} is an IS node (@code{@var{m}(k) < 1}), then
-## @code{@var{U}(k)} is the @emph{traffic intensity} defined as
-## @code{@var{X}(k)*@var{S}(k)}.
+## If @math{k} is a FCFS, LCFS-PR or PS node (@code{@var{m}(k) @geq{}
+## 1}), then @code{@var{U}(k)} is the utilization of center @math{k},
+## @math{0 @leq{} U(k) @leq{} 1}. If @math{k} is an IS node
+## (@code{@var{m}(k) < 1}), then @code{@var{U}(k)} is the @emph{traffic
+## intensity} defined as @code{@var{X}(k)*@var{S}(k)}. In this case the
+## value of @code{@var{U}(k)} may be greater than one.
 ##
 ## @item R
 ## @code{@var{R}(k)} is the response time at center @math{k}.
@@ -176,6 +177,18 @@
   U(i_single) = X(i_single) .* S(i_single);
   U(i_delay) = X(i_delay) .* S(i_delay);
   U(i_multi) = X(i_multi) .* S(i_multi) ./ m(i_multi);
+
+  if ( (any(U(i_multi)<-1000*eps) || any(U(i_multi)>1+1000*eps)) && any(m>1) )
+    warning("qn:numerical-instability",
+	    ["****\n" \
+	     "Some utilizations for M/M/1 or M/M/m centers are outside the\n" \
+	     "valid range [0,1]. Since the network contains multiple-server nodes\n" \
+	     "he problem is likely due to numerical instability of the Mean\n" \
+	     "Value Analysis algorithm. Note that this is an intrinsic problem\n" \
+	     "of MVA, not of the implementation used in this toolbox.\n" \
+	     "****\n"]);
+  endif
+    
 endfunction
 
 #{