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ego_script [2012/09/13 22:36]
hermann [Expression Calculation Syntax]
ego_script [2015/09/14 02:31] (current)
admin [Overview]
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 A simple EGO script model can be seen below: A simple EGO script model can be seen below:
  
-<​file ​cpp ego1.ego>​+<​file ​java ego1.ego>​
 Script {{ Script {{
   // Loads a GeoTiff map.   // Loads a GeoTiff map.
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 Here is a slightly more complex example: Here is a slightly more complex example:
  
-<​file ​cpp ego2.ego>​+<​file ​java ego2.ego>​
 Script {{ Script {{
   landscape := LoadCategoricalMap "​c:/​landscape.tif";​   landscape := LoadCategoricalMap "​c:/​landscape.tif";​
-  ​cells hects m2s := CalcAreas landscape;​ +  ​areas := CalcAreas landscape;​ 
-  ​SaveLookupTable hects "c:/area_in_hectares.csv";+  ​SaveTable areas "c:/areas.csv";
 }}; }};
 </​file>​ </​file>​
  
-Note that functor [[Calc Areas]] produces ​three lookup tables, representing the calculated area in cells, hectares and square meters.+Note that functor [[Calc Areas]] produces ​a table, representing the calculated area in cells, hectares and square meters.
  
 It is possible to omit variables representing outputs or ignore them using the variable ''​_''​ (underline). So the previous example can be re-written as shown below: It is possible to omit variables representing outputs or ignore them using the variable ''​_''​ (underline). So the previous example can be re-written as shown below:
  
-<​file ​cpp ego3.ego>​+<​file ​java ego3.ego>​
 Script {{ Script {{
   landscape := LoadCategoricalMap "​c:/​landscape.tif";​   landscape := LoadCategoricalMap "​c:/​landscape.tif";​
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 It is also possible to use the input and output names to bind variables and parameters. The previous example can be rewritten as It is also possible to use the input and output names to bind variables and parameters. The previous example can be rewritten as
  
-<​file ​cpp ego4.ego>​+<​file ​java ego4.ego>​
 Script {{ Script {{
   { landscape=map } := LoadCategoricalMap { filename="​c:/​landscape.tif"​ };   { landscape=map } := LoadCategoricalMap { filename="​c:/​landscape.tif"​ };
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 It is possible to freely mix both styles. So you can write the previous input as It is possible to freely mix both styles. So you can write the previous input as
  
-<​file ​cpp ego4.ego>​+<​file ​java ego4.ego>​
 Script {{ Script {{
   landscape := LoadCategoricalMap { filename="​c:/​landscape.tif"​ };   landscape := LoadCategoricalMap { filename="​c:/​landscape.tif"​ };
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 It is also possible to inline a definition of functor pretty much like nesting function calls in other programming languages: It is also possible to inline a definition of functor pretty much like nesting function calls in other programming languages:
  
-<​file ​cpp ego5.ego>​+<​file ​java ego5.ego>​
 Script {{ Script {{
   { hects=cellAreaInHectares } := CalcAreas (LoadCategoricalMap { filename="​c:/​landscape.tif"​ });   { hects=cellAreaInHectares } := CalcAreas (LoadCategoricalMap { filename="​c:/​landscape.tif"​ });
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 You can define a single line comment preceding the text with a '​%%//​%%'​. You can define a single line comment preceding the text with a '​%%//​%%'​.
  
-<​code ​cpp>+<​code ​java>
 // This is a single line comment. // This is a single line comment.
 </​code>​ </​code>​
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 Multi-line comments can be defined surrounding the text with '​%%/​*%%'​ and '​%%*/​%%'​. Multi-line comments can be defined surrounding the text with '​%%/​*%%'​ and '​%%*/​%%'​.
  
-<​code ​cpp>+<​code ​java>
 /* This is a multi-line /* This is a multi-line
 comment */ comment */
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 It is worth noting that there is a very important difference between both comment styles: multi-line comment style are not preserved if the model is opened using the graphical interface. Usually this is not a problem since multi-line comment can be defined using the '​%%//​%%'​ style. Ex: It is worth noting that there is a very important difference between both comment styles: multi-line comment style are not preserved if the model is opened using the graphical interface. Usually this is not a problem since multi-line comment can be defined using the '​%%//​%%'​ style. Ex:
  
-<​code ​cpp>+<​code ​java>
 // This is a multi-line // This is a multi-line
 // comment // comment
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 The sequence ''​===''​ is used to separate the brief and extended comments of a functor. The sequence ''​===''​ is used to separate the brief and extended comments of a functor.
  
-<​code ​cpp>+<​code ​java>
 // Generate the initial '​seed' ​ // Generate the initial '​seed' ​
 // //
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 The first syntax represents properties using comments. The first syntax represents properties using comments.
-<​code ​cpp>+<​code ​java>
 /** name = value */ /** name = value */
 </​code>​ </​code>​
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 The other syntax uses the special symbol @. The other syntax uses the special symbol @.
  
-<​code ​cpp>+<​code ​java>
 @name = value @name = value
 </​code>​ </​code>​
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 Examples of properties can be seen below: Examples of properties can be seen below:
  
-<​code ​cpp>+<​code ​java>
 /** /**
   dff.date = Wed Oct 21 18:19:21 2009   dff.date = Wed Oct 21 18:19:21 2009
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 </​code>​ </​code>​
  
-<​code ​cpp>+<​code ​java>
 @alias = Largest Patch Area @alias = Largest Patch Area
 @collapsed = yes @collapsed = yes
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 The syntax The syntax
  
-<​code ​cpp>+<​code ​java>
 // The input map.  // The input map. 
 // //
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 and and
  
-<​code ​cpp>+<​code ​java>
 @comment = "The input map.  @comment = "The input map. 
  
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 Since Dinamica EGO version 2.0, expressions in EGO Script can be represented using an additional special syntax. The example below illustrates:​ Since Dinamica EGO version 2.0, expressions in EGO Script can be represented using an additional special syntax. The example below illustrates:​
  
-<​code ​cpp>+<​code ​java>
 if #random <= ($mean - $min) / ($max - $min) then if #random <= ($mean - $min) / ($max - $min) then
    $min + sqrt(#​random * ($max - $min) * ($mean - $min))    $min + sqrt(#​random * ($max - $min) * ($mean - $min))
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 The use of sigils has some advantages including making easy to determine the data type represented by the variables. They also prevent clashes between special names like "​rand",​ "​line"​ and "​column"​ and the user defined ones. ((Using sigils the expression "rand + #rand" is the sum of a random value with a the value of map named "​rand"​)) The use of sigils has some advantages including making easy to determine the data type represented by the variables. They also prevent clashes between special names like "​rand",​ "​line"​ and "​column"​ and the user defined ones. ((Using sigils the expression "rand + #rand" is the sum of a random value with a the value of map named "​rand"​))
- 
-//However, keep in mind that this syntax is not fully compatible with the graphical interface and you may end up having an invalid model if you edit a model created using this syntax in the graphical interface.//​ 
  
 === Examples === === Examples ===
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 The example below represents a fragment of a real model using the original syntax: The example below represents a fragment of a real model using the original syntax:
  
-<​code ​cpp>+<​code ​java>
     patches := LoadCategoricalMap "​../​originals/​landscape.ers"​ .no .no 0 0 .none;     patches := LoadCategoricalMap "​../​originals/​landscape.ers"​ .no .no 0 0 .none;
     // ...     // ...
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 The model modified to use the special expression calculation syntax can be seen below: The model modified to use the special expression calculation syntax can be seen below:
  
-<​code ​cpp>+<​code ​java>
     patches := LoadCategoricalMap "​../​originals/​landscape.ers"​ .no .no 0 0 .none;     patches := LoadCategoricalMap "​../​originals/​landscape.ers"​ .no .no 0 0 .none;
     // ...     // ...
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     // Isolate the patches of a single category. ​     // Isolate the patches of a single category. ​
     @collapsed = yes     @collapsed = yes
-    singleCategoryPatches := #[ if #patches = $currenteCategoryId then 1 else null ];+    singleCategoryPatches := #[ if #patches = $currenteCategoryId then 1 else null ] .uint8 0 .no;
 </​code>​ </​code>​
 +
 +===== Complex Example =====
 +
 +<code java>
 +@title = Calc Patch Sizes, Mean Patch Sizes and Patch Size Standard Deviations
 +@author = Dinamica Team
 +@organization = CSR / UFMG
 +@metaversion = 1.0
 +@description = Calculate the patch sizes, the mean patch sizes and the patch size standard deviation of different categories.
 +@notes = "The model input is a map where the non-null values identify the patches.
 +
 +The output is a table per category containing the patch sizes and two additional tables containing the mean patch size and the patch size standard deviation per category."​
 +@showproperties = yes
 +@version = 1.9.32
 +Script {{
 +    // The input map. 
 +    //
 +    // Non-null values identify the patches. ​
 +    patches := LoadCategoricalMap "​../​originals/​landscape.ers"​ .no .no 0 0 .none .none;
 +
 +    ForEachCategory patches {{
 +        step = step;
 +
 +        // Patch size standard deviations. ​
 +        currentPatchSizeStandardDeviations := MuxLookupTable [
 +            "​Category"​ "​Patch_Size_Standard_Deviations_In_Hectares"​
 +        ] updatedPatchSizeStandardDeviations;​
 +
 +        // Mean Patch sizes. ​
 +        currentMeanPatchSizes := MuxLookupTable [
 +            "​Category"​ "​Mean_Patch_Sizes_In_Hectares"​
 +        ] updatedPatchMeans;​
 +
 +        // Current category. ​
 +        currentCategory := Step step;
 +
 +        // Calculate the sizes of a set of patches and their corresponding mean and 
 +        // standard deviation. ​
 +        @collapsed = yes
 +        Group {{
 +            // Isolate the patches of a single category. ​
 +            @collapsed = yes
 +            singleCategoryIndividualizedPatches := # [
 +                if #patches = $currentCategory then
 +                    #patches
 +                else 
 +                    null        ​
 +            ] .int32 .default .no .none;
 +
 +            // Calculate the patch size, the mean patch size and patch size standard ​
 +            // deviation. ​
 +            @collapsed = yes
 +            Group {{
 +                // Individualize the patches. ​
 +                individualizedPatches := CalcPatchLabelMap {
 +                    source = singleCategoryIndividualizedPatches,​
 +                    initialPatchLabel = 1,
 +                    onlyOrthogonalsAreAllowed = .no,
 +                    windowLines = 3,
 +                    windowColumns = 3,
 +                    cellType = .int32,
 +                    nullValue = .default,
 +                    patchLabelsAreSparse = .no
 +                };
 +
 +                attributes := ExtractMapAttributes individualizedPatches .yes .yes;
 +
 +                // Calculate the mean patch size. 
 +                //
 +                // The calculation uses the total patch size and the number of individual patches. ​
 +                @collapsed = yes
 +                mean := $ [
 +                    (%attributes["​cellArea"​] * %attributes["​nonNullCells"​] / %attributes["​uniqueCells"​]) ? 0
 +                ] .no 0;
 +
 +                // Calculate the patch sizes. ​
 +                _ patchSizesInHectares _ := CalcAreas individualizedPatches;​
 +
 +                // Calculate the patch size standard deviation. ​
 +                @collapsed = yes
 +                Group {{
 +                    // Calculate the patch size standard deviation. ​
 +                    @collapsed = no
 +                    LogPolicy .warning .no {{
 +                        // Calculate the SUM(Xi - MEAN)^2, where Xi is the current patch size. 
 +                        @collapsed = yes
 +                        ForEachCategory individualizedPatches {{
 +                            step0 = step;
 +
 +                            // Accumulated value of SUM(Xi - MEAN)^2. ​
 +                            currentAccumulatedValue := MuxValue 0 updatedAccumulatedValue;​
 +
 +                            // Current patch id. 
 +                            currentPatchId := Step step0;
 +
 +                            // Calculate the updated accumulated value of SUM(Xi - MEAN)^2 for the current ​
 +                            // patch size. 
 +                            @collapsed = yes
 +                            updatedAccumulatedValue := $ [
 +                                $currentAccumulatedValue + ((%patchSizesInHectares[$currentPatchId] - $mean) ^ 2)
 +                            ] .no 0;
 +                        }};
 +                    }};
 +
 +                    // Provide 0 as the default accumulated value even if the input map has no patches ​
 +                    // for the current categories. ​
 +                    accumulatedValue := ValueJunction updatedAccumulatedValue 0;
 +
 +                    // Calculate the standard deviation using the SUM(Xi - MEAN)^2. ​
 +                    @collapsed = yes
 +                    standardDeviation := $ [
 +                        sqrt($accumulatedValue / %attributes["​uniqueCells"​]) ? 0
 +                    ] .no 0;
 +                }};
 +
 +                // Update the mean table with the mean patch size of the current category. ​
 +                updatedPatchMeans := SetLookupTableValue currentMeanPatchSizes currentCategory mean;
 +
 +                // Update the table of standard deviations with the standard deviation of the 
 +                // current category. ​
 +                updatedPatchSizeStandardDeviations := SetLookupTableValue currentPatchSizeStandardDeviations currentCategory standardDeviation;​
 +            }};
 +        }};
 +
 +        // Save a table of patch sizes per category. ​
 +        SaveLookupTable patchSizesInHectares "​patch_sizes.csv"​ 2 step .none;
 +    }};
 +
 +    // Save the mean patch sizes as a table. ​
 +    SaveLookupTable updatedPatchMeans "​mean_patch_sizes.csv"​ 2 .none .none;
 +
 +    // Save the patch size standard deviations as a table. ​
 +    SaveLookupTable updatedPatchSizeStandardDeviations "​patch_size_standard_deviations.csv"​ 2 .none .none;
 +}};
 +</​code>​
 +