# [Bug 577] Getting started guide typos and improvements

 Submitted by klaas on Wed, 2008-07-16 14:10

--- Comment #1 from Klaas Gadeyne <klaas [dot] gadeyne [..] ...> 2008-07-16 15:57:59 ---
> See

[kgad@ampere ~/SVN/orocos/bfl-trunk/docs]$svn diff getting_started_guide.tex Index: getting_started_guide.tex =================================================================== --- getting_started_guide.tex (revision 29443) +++ getting_started_guide.tex (working copy) @@ -639,7 +639,7 @@ \end{verbatim} The derivative according to the state is a 3x3 matrix calculated by: \begin{verbatim} - Matrix df(3,3);d + Matrix df(3,3); df(1,1)=1; df(1,2)=0; df(1,3)=-vel(1)*sin(state(3)); @@ -873,8 +873,8 @@ \begin{verbatim} namespace BFL { - class NonLlinearSystemPdf: - public ConditionlPdf MatrixWrapper::ColumnVector> + class NonLinearSystemPdf: + public ConditionalPdf MatrixWrapper::ColumnVector> { public: NonlinearSystemPdf( const Gaussian& additiveNoise); [kgad@ampere ~/SVN/orocos/bfl-trunk/docs]$
svn commit -m "fix small typos. Part of fix for bug #577. Thx weaker at
directbox com" getting_started_guide.tex
Sending getting_started_guide.tex
Transmitting file data .
Committed revision 29444.

### [Bug 577] New: Getting started guide typos and improvements

Summary: Getting started guide typos and improvements
Product: BFL
Version: trunk
Platform: All
OS/Version: All
Status: NEW
Severity: normal
Priority: P2
Component: documentation
AssignedTo: bfl [..] ...
ReportedBy: klaas [dot] gadeyne [..] ...
CC: bfl [..] ...
Estimated Hours: 0.0

See

### [Bug 577] Getting started guide typos and improvements

Tinne De Laet <tinne [dot] delaet [..] ...> changed:

--------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED

--- Comment #3 from Tinne De Laet <tinne [dot] delaet [..] ...> 2008-12-03 09:58:04 ---
...
>
> I found some typos and things that weren't clear to me in the tutorial.
> This thread is for corrections and suggestions regarding the "Getting
> started/Introduction to BFL" tutorial.
>
> unclear:
> 2.2.1: Although the first example is fully linear, extendedkalmanfilter.h
> is included. This is somehow misleading. Why not just kalmanfilter.h?
I included an extra explanation in the new tutorial.

> consistency:
> 2.2.4: In the example files the prior density is named "prior_cont", but in
> the tutorial just "prior". The same applies to 2.3.4 where both names
> appear.
I changed the name to prior in the code.
> unclear:
> 2.2.7: When getting the posterior with PostGet() there is "my_filter" out
> of nowhere. Shouldn't it be just "filter"?
Indeed: adapted in the new tutorial.
>
> typo:
> 2.3.2: When creating the derivative there is a 'd' after the ';' - it reads
> "Matrix df(3,3);d"
ok
>
> unclear:
> 2.4.2: It says we need to implement only _one_ function called
> SampleFrom(). A few lines later there is talk about implementing
> "ExpectedValueGet()". I think the statement "one function" is wrong, as
> ExpectedValueGet() has also to be provided.
No, only SampleFrom is needed. This was just a mistake in the explanation,
ExpectedValueGet should be replaced with SampleFrom.

> typo:
> 2.4.3: The constructor has two typos: NonLlinearMeasurementPdf (one 'l' too
> much) and ConditionlPdf (missing 'a').
indeed

> unclear:
> 2.4.3: Same as in 2.4.2: It says we need to implement only _one_ function
> called ProbabilityGet(). A few lines later there is again talk about
> implementing "ExpectedValueGet()". Is this a copy/paste error?
Indeed a copy paste error: ExpectedValueGet should be replaced with
ProbabilityGet().

> consistency:
> 2.4.3: When returning the probability of the expected value there is an
> additional "-measurement" in the example files. return
> _measNoise.ProbabilityGet(expected_measurement-measurement);
ok, now the text also mentiones this difference
>
> Additionally, before diving right into the examples a short outline of the
> procedure would have helped me. Like for example:
>
> System model:
> - create (gaussian) density to model system uncertainty
> - create pdf class depending on your problem (not necessary in the linear
> case) - implement necessary functions for intended filter
> - instantiation of that pdf class
> - creating system model from pdf
>
> Measurement model:
> - create (gaussian) density to model measurement uncertainty
> - create pdf class depending on your measurment characteristics (not
> necessary in the linear case) - implement necessary functions for intended
> filter
> - instantiation of that pdf class
> - create measurement model from pdf
>
> Final steps:
> - create prior density
> - create filter using prior
In the new tutorial I added an extra section with an outline as you suggested.
>
> I think BFL is a very fine piece of software and want to thank all the
> contributors!
Thank you for contributing to the project!

Changes to the code:
svn commit
Sending examples/linear_kalman/test_linear_kalman.cpp
Transmitting file data .
Committed revision 29763.

Changes to the tutorial text:
svn commit
Sending docs/getting_started_guide.tex
Transmitting file data .
Committed revision 29767.

Tinne