1 | /*! |
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2 | |
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3 | \page maps How to write your own maps |
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4 | |
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5 | \section read-maps Readable Maps |
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6 | |
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7 | The readable maps are very frequently used as the input of the |
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8 | algorithms. For this purpose the most straightforward is to use the |
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9 | maps provided by Hugo's graph structres. Very often however, it is more |
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10 | convenient and/or more efficient to write your own readable map. |
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11 | |
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12 | You can find some examples below. |
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13 | |
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14 | This simple map assigns \f$\pi\f$ to each edge. |
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15 | |
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16 | \code |
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17 | struct MyMap |
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18 | { |
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19 | typedef double ValueType; |
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20 | double operator[](Graph::Edge e) const { return M_PI;} |
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21 | }; |
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22 | \endcode |
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23 | |
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24 | An alternative way to define maps. For this, \c MapBase seems to |
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25 | be a better name then \c NullMap |
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26 | |
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27 | \code |
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28 | struct MyMap : public MapBase<Edge,double> |
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29 | { |
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30 | double operator[](Graph::Edge e) const { return M_PI;} |
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31 | }; |
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32 | \endcode |
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33 | |
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34 | Or, if we had \c KeyType and \c ValueType |
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35 | |
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36 | \code |
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37 | struct MyMap : public MapBase<Edge,double> |
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38 | { |
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39 | ValueType operator[](KeyType e) const { return M_PI;} |
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40 | }; |
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41 | \endcode |
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42 | |
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43 | |
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44 | Here is a more complex example. It provides a length function which is obtained |
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45 | from a base length function modified by a potential difference. |
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46 | |
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47 | \code |
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48 | class MyLengthMap |
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49 | { |
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50 | const Graph::EdgeMap &ol; |
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51 | const Graph::NodeMap &pot; |
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52 | |
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53 | public: |
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54 | typedef double ValueType; |
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55 | |
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56 | double operator[](Graph::Edge e) const { |
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57 | return ol.get(e)-pot.get(v)-pot.get(u); |
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58 | } |
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59 | |
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60 | MyComplexMap(const Graph::EdgeMap &o,const Graph::NodeMap &p) : |
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61 | ol(o), pot(p); |
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62 | }; |
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63 | \endcode |
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64 | |
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65 | \todo Please improve on the english. |
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66 | \todo Don't we need \e to \e require a 'typedef xxx KeyType' tag, as well? |
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67 | */ |
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