| 1 | /*! |
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| 2 | \page userguide_merg BDM Use - Merging of probability distributions |
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| 3 | |
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| 4 | Merging is an operation which combines information from many \c source pdfs into one, the \c merger. |
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| 5 | |
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| 6 | The very basic merger requires that the sources are defined on the same variables. |
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| 7 | |
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| 8 | \section ug_mer_mat Matlab class mexMerger |
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| 9 | |
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| 10 | All mergers in Matlab are derived from a class mexMerger which has only the list of \c sources, their \c weights, the resulting pdf, the \c merger, and operations merge() and validate(). |
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| 11 | |
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| 12 | \code |
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| 13 | classdef mexMerger |
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| 14 | properties |
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| 15 | %> weights of the merged densities |
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| 16 | weights |
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| 17 | %> source pdfs to be merged |
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| 18 | sources |
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| 19 | %> merged density - any pdf understood by epdf_* functions |
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| 20 | merger |
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| 21 | end |
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| 22 | |
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| 23 | methods |
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| 24 | function obj=validate(obj) |
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| 25 | % e.g. check if all sources are compatible |
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| 26 | end |
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| 27 | %> Merge sources into the merger |
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| 28 | function obj=merge(obj) |
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| 29 | % transform old estimate into new estimate |
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| 30 | end |
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| 31 | end |
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| 32 | end |
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| 33 | \endcode |
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| 34 | Validate has the same meaning as in previous chapters, i.e. it is called before any use of the class to check that all elements has been set-up correctly. |
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| 35 | |
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| 36 | Except form that, only few technical functions are needed for integration with C++ classes in BDM, see mexMerger. |
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| 37 | |
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| 38 | mexMErger is an abstract class, which has no operation defined. In order to achieve some functionality an offspring need to be defined. |
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| 39 | An example of one possible offspring is in class mexGaussMergerArit which implements Arithmetic merging of source pdfs which are converted into Gaussians using moment matching. |
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| 40 | |
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| 41 | The offspring only redefines methods validate and merge. |
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| 42 | |
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| 43 | An example how to use this class is in bdmtoolbox/tutorial/merging/merge_mex.m |
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| 44 | \code |
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| 45 | clear all |
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| 46 | pdfs |
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| 47 | |
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| 48 | % merger |
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| 49 | M=mexGaussMergerArit; |
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| 50 | M.weights = [0.5, 0.5]; |
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| 51 | M.sources = {N1a,Ga}; |
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| 52 | M=M.validate(); |
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| 53 | |
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| 54 | M=M.merge(); |
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| 55 | |
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| 56 | figure(1); |
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| 57 | h=epdf_1dplot(N1a); |
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| 58 | set(h,'LineStyle','--'); |
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| 59 | hold on |
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| 60 | h=epdf_1dplot(Ga); |
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| 61 | set(h,'LineStyle','--'); |
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| 62 | |
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| 63 | |
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| 64 | epdf_1dplot(M.merger); |
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| 65 | \endcode |
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| 66 | |
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| 67 | |
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| 68 | For list of all Matlab mergers, see <a href="annotated.html"> list </a>. |
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| 69 | |
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| 70 | \section ug_mer_c Mergers from BDM |
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| 71 | |
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| 72 | More advanced mergers allowing to merge pdfs on partially overlapping variables are available in BDM, specifically, classes bdm::MergerBase and bdm::merger_mix. |
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| 73 | |
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| 74 | Their use is demonstrated in examples: bdmtoolbox/tutorial/merging/merge_grid.m and merge_mix.m, respectively. |
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| 75 | */ |
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