From: <mma...@us...> - 2012-03-24 14:31:14
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Revision: 10022 http://octave.svn.sourceforge.net/octave/?rev=10022&view=rev Author: mmarzolla Date: 2012-03-24 14:31:07 +0000 (Sat, 24 Mar 2012) Log Message: ----------- fixed typos Modified Paths: -------------- trunk/octave-forge/main/queueing/doc/contributing.txi trunk/octave-forge/main/queueing/doc/markovchains.txi trunk/octave-forge/main/queueing/doc/summary.txi Modified: trunk/octave-forge/main/queueing/doc/contributing.txi =================================================================== --- trunk/octave-forge/main/queueing/doc/contributing.txi 2012-03-24 11:11:08 UTC (rev 10021) +++ trunk/octave-forge/main/queueing/doc/contributing.txi 2012-03-24 14:31:07 UTC (rev 10022) @@ -30,32 +30,28 @@ @item If you are contributing a new function, please embed proper documentation within the function itself. The documentation must be in -@code{texinfo} format, so that it will be extracted and formatted into +@code{texinfo} format, so that it can be extracted and formatted into the printable manual. See the existing functions of the @code{queueing} package for the documentation style. -@item The documentation should be as precise as possible. In particular, -always state what the valid ranges of the parameters are. - -@item If you are contributing a new function, ensure that the function +@item Make sure that each new function properly checks the validity of its input parameters. For example, each function accepting vectors should check whether the dimensions match. -@item Always provide bibliographic references for each algorithm you +@item Provide bibliographic references for each new algorithm you contribute. If your implementation differs in some way from the reference you give, please describe how and why your implementation -differs. +differs. Add references to the @file{doc/references.txi} file. -@item Include Octave test and demo blocks with your code. -Test blocks are particularly important, because Queueing Network -algorithms tend to be quite complex to implement correctly, and we -must ensure that the implementations provided with the -@code{queueing} package are (mostly) correct. +@item Include test and demo blocks with your code. +Test blocks are particularly important, since most algorithms tend to +be quite tricky to implement correctly. If appropriate, test blocks +should also verify that the function fails on incorrect input +parameters. @end itemize Send your contribution to Moreno Marzolla -(@email{marzolla@@cs.unibo.it}). Even if you are just a user of -@code{queueing}, and find this package useful, let me know by -dropping me a line. Thanks. +(@email{marzolla@@cs.unibo.it}). If you are just a user of this +package and find it useful, let me know by dropping me a line. Thanks. Modified: trunk/octave-forge/main/queueing/doc/markovchains.txi =================================================================== --- trunk/octave-forge/main/queueing/doc/markovchains.txi 2012-03-24 11:11:08 UTC (rev 10021) +++ trunk/octave-forge/main/queueing/doc/markovchains.txi 2012-03-24 14:31:07 UTC (rev 10022) @@ -249,8 +249,11 @@ @noindent where @math{{\bf \pi}(i) = {\bf \pi}(0){\bf P}^i} is the state occupancy probability after @math{i} transitions. -If @math{\bf P} has absorbing states, that is, states with no out -transitions, we can rearrange the states to rewrite @math{\bf P} as: +If @math{\bf P} is absorbing, i.e., the stochastic process eventually +reaches with probability 1 a state with no outgoing transitions, then +we can compute the expected number of visits until absorption +@math{\bf L}. To do so, we first rearrange the states to rewrite +matrix @math{\bf P} as: @iftex @tex @@ -271,12 +274,11 @@ @noindent where the first @math{t} states are transient and the last @math{r} states are absorbing (@math{t+r = N}). The matrix @math{{\bf N} = ({\bf I} - {\bf Q})^{-1}} is called the -@emph{fundamental matrix}; @math{N(i,j)} represents the expected -number of times that the process is in the @math{j}-th transient state -if it is started in the @math{i}-th transient state. If we reshape -@math{\bf N} to the size of @math{\bf P} (filling missing entries with -zeros), we have that, for absorbing chains @math{{\bf L} = {\bf -\pi}(0){\bf N}}. +@emph{fundamental matrix}; @math{N_{i,j}} is the expected number of +times that the process is in the @math{j}-th transient state if it +started in the @math{i}-th transient state. If we reshape @math{\bf N} +to the size of @math{\bf P} (filling missing entries with zeros), we +have that, for absorbing chains @math{{\bf L} = {\bf \pi}(0){\bf N}}. @DOCSTRING(dtmc_exps) @@ -293,11 +295,11 @@ The @emph{mean time to absorption} is defined as the average number of transitions which are required to reach an absorbing state, starting from a transient state (or given an initial state occupancy -probability vector @math{{\bf \pi}(0)} ). +probability vector @math{{\bf \pi}(0)}). -Let @math{{\bf t}_i} be the expected number of steps before being -absorbed in any absorbing state, starting from state @math{i}. Vector -@math{\bf t} can be easiliy computed from the fundamental matrix +Let @math{{\bf t}_i} be the expected number of transitions before +being absorbed in any absorbing state, starting from state @math{i}. +Vector @math{\bf t} can be computed from the fundamental matrix @math{\bf N} (@pxref{Expected number of visits (DTMC)}) as @iftex @@ -311,10 +313,10 @@ @end example @end ifnottex -We can define a matrix @math{{\bf B} = [ B_{i, j} ]} such that -@math{B_{i, j}} is the probability of being absorbed in state -@math{j}, starting from transient state @math{i}. Again, using -the fundamental matrix @math{\bf N} and @math{\bf R}, we have +Let @math{{\bf B} = [ B_{i, j} ]} be a matrix where @math{B_{i, j}} is +the probability of being absorbed in state @math{j}, starting from +transient state @math{i}. Again, using matrices @math{\bf N} and +@math{\bf R} (@pxref{Expected number of visits (DTMC)}) we can write @iftex @tex @@ -333,9 +335,9 @@ @node First passage times (DTMC) @subsection First Passage Times -The First Passage Time @math{M_{i, j}} is defined as the average -number of transitions needed to visit state @math{j} for the first -time, starting from state @math{i}. Matrix @math{\bf M} satisfies the +The First Passage Time @math{M_{i, j}} is the average number of +transitions needed to visit state @math{j} for the first time, +starting from state @math{i}. Matrix @math{\bf M} satisfies the property that @iftex @@ -359,7 +361,7 @@ used. Let @math{\bf W} be the @math{N \times N} matrix having each row equal to the steady-state probability vector @math{\bf \pi} for @math{\bf P}; let @math{\bf I} be the @math{N \times N} identity -matrix. Define matrix @math{\bf Z} as follows: +matrix. Define @math{\bf Z} as follows: @iftex @tex @@ -393,10 +395,9 @@ @end ifnottex According to the definition above, @math{M_{i,i} = 0}. We arbitrarily -redefine @math{M_{i,i}} to be the @emph{mean recurrence time} -@math{r_i} for state @math{i}, that is the average number of -transitions needed to return to state @math{i} starting from -it. @math{r_i} is defined as: +let @math{M_{i,i}} to be the @emph{mean recurrence time} @math{r_i} +for state @math{i}, that is the average number of transitions needed +to return to state @math{i} starting from it. @math{r_i} is: @iftex @tex @@ -413,9 +414,6 @@ @end example @end ifnottex -@noindent where @math{\pi_i} is the stationary probability of visiting state -@math{i}. - @DOCSTRING(dtmc_fpt) @c Modified: trunk/octave-forge/main/queueing/doc/summary.txi =================================================================== --- trunk/octave-forge/main/queueing/doc/summary.txi 2012-03-24 11:11:08 UTC (rev 10021) +++ trunk/octave-forge/main/queueing/doc/summary.txi 2012-03-24 14:31:07 UTC (rev 10022) @@ -65,15 +65,14 @@ @item @math{M/H_m/1} (Hyperexponential service time distribution) @end itemize -Functions for Markov chain analysis are also provided, for discrete-time -chains (DTMC) or continuous-time chains (CTMC): +Functions for Markov chain analysis are also provided: @itemize @item Birth-death process; @item Transient and steady-state occupancy probabilities; @item Mean times to absorption; -@item Expected sojourn times and time-averaged sojourn times (CTMC only); +@item Expected sojourn times and time-averaged sojourn times; @item Mean first passage times; @end itemize This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site. |