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--- visual3d:documentation:pipeline:expressions:overview [2024/06/19 12:49] – sgranger
+++ visual3d:documentation:pipeline:expressions:overview [2024/07/12 13:29] (current) – removed sgranger
@@ Line 1: / Line 1: @@
-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]]**