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--- visual3d:documentation:pipeline:expressions:overview [2024/07/03 17:40] – created sgranger
+++ visual3d:documentation:pipeline:expressions:overview [2024/07/12 13:29] (current) – removed sgranger
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-====== Overview ======
-Many (but not all) edit boxes and pipeline command parameters allow the use of expressions instead of numerical values. Visual3D uses a common expression parser, so the following syntax is common across all command parameters that allow expressions.
-==== Evaluate_Expression Command ====
-The Evaluate_Expression command allows the users to include expressions for defining the processing of the signals.
-Evaluate_Expression
-/Expression=
-!/Signal_Type=
-!/Signal_Folder=
-!/Signal_Name=
-/Result_Type=
-/Result_Folder=
-/Result_Name=
-!/Apply_as_suffix_to_signal_name=FALSE
-**;**
-=== Expression_Items ===
-[[Visual3D:Documentation:Pipeline:Expressions:Expression_Items#Data_Tree|Data Tree Signals]]
-[[Visual3D:Documentation:Pipeline:Expressions:Expression_Items#Model_Builder|Expressions_in_Model_Builder_Mode]]
-[[Visual3D:Documentation:Pipeline:Expressions:Expression_Items#Pipeline_Parameters|Pipeline_Parameters]]
-[[Visual3D:Documentation:Pipeline:Expressions:Expression_Items#Tags|Tags]]
-[[Visual3D:Documentation:Pipeline:Expressions:Expression_Items#C3D_Parameters|C3D_Parameters]]
-[[Visual3D:Documentation:Pipeline:Expressions:Expression_Items#Model_Metrics|Model Metrics]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data|String Data]]
-=== Visual3D Reserved Characters ===
-There are five characters that cause the equation parser considerable trouble. We have introduced reserved pipeline commands that can be used in the place of these characters.
-|Reserved_Characters                                                            |             |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Characters#Amp|&]]      |Ampersand    |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Characters#Colon|:]]    |Colon        |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Characters#Semicolon|;]]|Semicolon    |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Characters#Plus|+]]     |Plus         |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Characters#FSlash|/]]   |Forward Slash|
-=== Visual3D Reserved Names ===
-|Reserved_Names                                                                              |                           |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Names#CURRENT_SIGNAL|CURRENT_SIGNAL]]|short hand for signal names|
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Names#NAN|NAN]]                      |Not a Number               |
-|[[Visual3D:Documentation:Pipeline:Expressions:Reserved_Names#isNAN|isNAN]]                  |Is Not a Number?           |
-=== Numbers ===
-|Mathematical Constants                                                          |                                                                                                    |
-|pi()                                                                            |3.14159265358979323846                                                                              |
-|gravity_vector()                                                                |gravity vector in the laboratory coordinate system. For a z-up coordinate system returns (0,0,-9.81)|
-|[[Visual3D:Documentation:Pipeline:Expressions:Expression_Numbers#random|rand()]]|Generate a random number                                                                            |
-=== Mathematical Operators ===
-**Note: Visual3D parses the mathematical operators before it parses the signal names. If you have a signal name that contains a mathematical operator (e.g. R-Foot1), Visual3D will probably not be able to parse the equation expression properly.**
-**Also Note the potential conflict between some of the operators and the reserved characters. If the string is obviously an expression, there is no conflict.**
-|Mathematical Operators                                                                                 |                                            |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Plus|+]]                         |Plus or Add                                 |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Minus|-]]                        |Minus or Subtract                           |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Multiply|*]]                     |Multiply                                    |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Divide|/]]                       |Divide                                      |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Power|^]]                        |Power -> for example, x^2 = x to the power 2|
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Logical_Or||]]                   |logical OR -> the adjective NOT is allowed  |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Logical_And|&]]                  |logical AND -> the adjective NOT is allowed |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Equals|== OR =]]                 |Equals                                      |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Not_Equals|<> OR ><]]            |Not Equals                                  |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Less_Than|<]]                    |Less Than                                   |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Less_Than_Or_Equals|<= OR =<]]   |Less Than or Equals To                      |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Greater_Than|>]]                 |Greater Than                                |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#Greater_Than_Or_Equals|>= OR =>]]|Greater Than or Equals To                   |
-|[[Visual3D:Documentation:Pipeline:Expressions:Mathematical_Operators_#NOT|NOT()]]                      |NOT()                                       |
-== The ugly truth of the logical and ==
-& is used by Visual3D for concatenating strings
-it works quite well, but there is one circumstance where this choice of delimiter is a nuisance.
-and that is when you want & to actually be a logical and and the parser throws it away
-in this case you can use the reserved string AMP
-it was only really ugly before version 2024_04 because it didn't work before then
-Example given a file that has TAGS labelled TEST1 and TEST2
-To select files containing the tags TEST1 and TEST2
-Select_Active_File
-/FILE_NAME=ALL_FILES
-/QUERY=TEST1 & TEST2
-! /SUBJECT_TAGS=NO_SUBJECT
-**;**
-! But what if you want to generalize and use another pipeline parameter for TEST2
-Set_Pipeline_Parameter
-/PARAMETER_NAME=SCOTT2
-/PARAMETER_VALUE=TEST1 &::AMP &::SCOTT
-**;**
-Select_Active_File
-/FILE_NAME=ALL_FILES
-/QUERY=TEST1 &::AMP &::SCOTT
-! /SUBJECT_TAGS=NO_SUBJECT
-**;**
-=== Brackets ===
-|Brackets                                                                    |                                    |
-|[[Visual3D:Documentation:Pipeline:Expressions:Brackets#Parentheses|( )]]    |contain the parameters in a function|
-|[[Visual3D:Documentation:Pipeline:Expressions:Brackets#Square_Brackets|[ ]]]|specify frame numbers and components|
-==== Functions ====
-Visual3D has pre-defined functions imbedded in the pipeline to help you out.
-These functions are commonly used or have been added based on customer use.
-===  Metric Functions ===
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Minimum|Metric_Minimum]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Maximum|Metric_Maximum]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Range|Metric_Range]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Mean|Metric_Mean]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Median|Metric_Median]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_StdDev|Metric_StdDev]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_RMS|Metric_RMS]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Sum|Metric_Sum]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_Integrate|Metric_Integrate]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Metric_InterQuartile|Metric_InterQuartile]]
-[[Visual3D:Documentation:Pipeline:Expressions:Metric_Functions#Cross_Correlation|Cross_Correlation]]
-===  Signal Functions ===
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Data_Exists|Data Exists]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Frame_Count|Frame_Count]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Add|Add]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Sort|Sort]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Transpose|Transpose]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Interpolate|Interpolate]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#First_Derivative|First Derivative]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Second_Derivative|Second Derivative]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Resolve_Discontinuity|Resolve_Discontinuity]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Indefinite_Integral|Indefinite_Integral]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Point_Relative_To_3Points|Point_Relative_To_3Points]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Snip|Snip]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Spline|Spline]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Point_Relative_To_3Points|Point_Relative_To_3Points]]
-[[Visual3D:Documentation:Pipeline:Expressions:Signal_Functions#Append_As...|Append_As]]
-=== String Data ===
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#Syntax|Specifying String Data]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#Modify|Modifying String Data]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#Parsing|Parsing String Data]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_Left|String_Left]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_Right|String_Right]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_Mid|String_Mid]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_Find|String_Find]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_Reverse_Find|String_Reverse_Find]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_To_Lower|String_To_Lower]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#String_To_Upper|String_To_Upper]]
-[[Visual3D:Documentation:Pipeline:General_Information:String_Data#To_String|To_String]]
-=== Least Squares Fitting of Data ===
-[[Visual3D:Documentation:Pipeline:Expressions:Least_Squares_Fitting_of_Data#Best_Fit_Plane|Best_Fit_Plane]]
-[[Visual3D:Documentation:Pipeline:Expressions:Least_Squares_Fitting_of_Data#Best_Fit_Circle|Best_Fit_Circle]]
-[[Visual3D:Documentation:Pipeline:Expressions:Least_Squares_Fitting_of_Data#Best_Fit_Sphere|Best_Fit_Sphere]]
-[[Visual3D:Documentation:Pipeline:Expressions:Least_Squares_Fitting_of_Data#Simple_Linear_Regression|Simple_Linear_Regression]]
-===  Intersection Functions ===
-[[Visual3D:Documentation:Pipeline:Expressions:Intersection_Functions#Line_Line_Intersect|Line_Line_Intersect]]
-[[Visual3D:Documentation:Pipeline:Expressions:Intersection_Functions#Line_Plane_Intersect|Line_Plane_Intersect]]
-[[Visual3D:Documentation:Pipeline:Expressions:Intersection_Functions#Project_Point_On_Plane|Project_Point_On_Plane]]
-[[Visual3D:Documentation:Pipeline:Expressions:Intersection_Functions#Point_Distance_To_Plane|Point_Distance_To_Plane]]
-[[Visual3D:Documentation:Pipeline:Expressions:Intersection_Functions#Point_Distance_To_Line|Point_Distance_To_Line]]
-[[Visual3D:Documentation:Pipeline:Expressions:Intersection_Functions#Is_Point_Inside_Polygon|Is_Point_Inside_Polygon]]
-=== Assigned Force Functions ===
-[[Visual3D:Documentation:Pipeline:Expressions:Assigned_Force_Functions#Forces|Force]]
-[[Visual3D:Documentation:Pipeline:Expressions:Assigned_Force_Functions#Center_Of_Pressure|Center Of Pressure]]
-[[Visual3D:Documentation:Pipeline:Expressions:Assigned_Force_Functions#Free_Moment|Free Moment]]
-=== Trigonometric Functions ===
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Cosine|Cosine]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Sine|Sine]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Tangent|Tangent]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Cotangent|Cotangent]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Arctangent|Arctangent]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Cosine|Cosine]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Arcsine|Arcsine]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#ArcCos|ArcCos]]
-[[Visual3D:Documentation:Pipeline:Expressions:Trigonometric_Functions#Arctan2|Arctan2]]
-===  Array and Matrix Functions ===
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#Vector|Vector]]
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#Unit_Vector|Unit_Vector]]
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#List|List]]
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#Rotation_Multiply|Rotation_Multiply]]
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#Rotation_Inverse|Rotation_Inverse]]
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#Rotation_Transpose|Rotation_Transpose]]
-[[Visual3D:Documentation:Pipeline:Expressions:Array_and_Matrix_Functions#Pose_Euler2Rotation4x4|Pose_Euler2Rotation4x4]]
-=== Common Math Expressions ===
-**int(a**) - truncate each component to the nearest integer
-**round(a)** - round each component to the nearest integer
-**fmod(y,x)** - Returns the floating-point remainder of y/x
-=> y and x must be one dimensional signals; returns a one dimensional signal
-**abs(a)** - absolute value
-**sign(a)**= sign of the signal ((a<0)=-1, (a>0)=1, (a==0) = 0
-**sqrt(a)** - square root
-**exp(a)** - exponent
-**log(a)** - natural log
-**log10(a)** - log base 10
-**length(x)** -- creates the length (magnitude) of a vector
-**distance(a,b)** -- distance between two signals.
-Example
-Evaluate_Expression
-/Expression= distance(LANDMARK::ORIGINAL::RIGHT_HIP , TARGET::ORIGINAL::LHIP)
-/Result_Name=PROX_THIGH_RADIUS
-! /Result_Type=DERIVED
-! /Result_Folder=PROCESSED
-**;**
-\\
-**dot (a, b)** -- creates the dot product of a and b
-**cross (a, b)** -- creates the cross product of a and b
-**NOTE: Often you will want to do dot (a, b)/ length (b), or cross (a, b) / length (b)**
-==== Expression Examples ====
-Examples of using Evaluate_Expressions can be found here: **[[Visual3D:Documentation:Pipeline:Expressions:Examples|Expressions Examples]]**