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--- visual3d:documentation:pipeline:signal_commands:indefinite_integral [2024/06/19 13:38] – removed sgranger
+++ visual3d:documentation:pipeline:signal_commands:indefinite_integral [2024/09/09 20:09] (current) – Cleaned up the page and began applying the pipeline page format. wikisysop
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+====== Indefinite Integral ======
+This pipeline command computes an indefinite integral from the start event to the stop event. This is a cumulative integral, with the value of each frame indicating the cumulative sum from the start event's initial value. This cumulative sum process uses the [[http://en.wikipedia.org/wiki/Trapezoidal_rule|trapezoidal rule]].
+For a given signal, s, the value of its integral at a given frame at time t is computed from the previous frame, at time t-1, as follows:
+<code>
+integral (t) = integral (t-1) + ((s(t)+s(t-1))* T / 2)
+</code>
+where T = time between frames (this is the data rate)
+===== Command =====
+The command can be edited via text editor. The details on the command are found below:
+<code>
+Indefinite_Integral
+/Signal_Types=The type of signal to be evaluated
+/Signal_Folder=The name of the signal folder
+/Signal_Names=The name of the signal to be evaluated
+/Result_Types=The type of signal to be evaluated
+/Result_Folder= The name of the resulting folder
+/Result_Names= The names of the resulting signal. If left blank the same number is used
+/Apply_As_Suffix_To_Signal_Name=The result is given the same name as the original signal with the suffix added
+/Event_Sequence= The event sequence
+/Exclude_Events= The exclude events
+/Event_Instance= The instance of the event sequence
+/Initial_Value= The value of the integral at the start event
+;
+</code>
+==== Notes ====
+The [[Visual3D:Documentation:Pipeline:Metric_Commands:Metric_Integrate|Metric_Integrate]] command will return the integral as a metric.
+Valid Result_Types are restricted according to the Signal_Types that are input into the command. If the Signal_Types are from the [[visual3d:documentation:c3d_signal_types:target_data_type|TARGET]] data type, then the result type can only be [[visual3d:documentation:c3d_signal_types:target_data_type|TARGET]], [[visual3d:documentation:visual3d_signal_types:derived_data_type|DERIVED]], or [[visual3d:documentation:visual3d_signal_types:metric_data_type|METRIC]].
+The Initial_Value parameter, if used, must be a signal expression that can return multiple components. The same Initial_Value expression is used for all signals.
+==== Examples ====
+This example calculates the velocity of the center of mass from force platform data during a vertical jump using the **Indefinite_Integral** command. Constants of integration (initial value) must be determined. In this case, the initial value is the initial velocity at the start of the preparation for the jump which is zero.
+**Note:** This is only an example and you should check the constants of integration for your analysis.
+<code>
+!************************************************************************
+! Take the vertical GRF, subtract the body weight, and divide the
+! result by body mass to get the vertical CoM acceleration
+!************************************************************************
+! Add the two signals from F1 and F2 - end result is GRF for both plates
+Add_Signals
+/SIGNAL_TYPES=FORCE+FORCE
+/SIGNAL_NAMES=FP1+FP2
+/SIGNAL_FOLDER=PROCESSED+PROCESSED
+/RESULT_NAME=GRF
+/RESULT_FOLDER=PROCESSED
+;
+! Subtract the body weight in N - Metric is MASS_N
+Subtract_Signals
+/SIGNAL_TYPES=DERIVED+METRIC
+/SIGNAL_FOLDER=PROCESSED
+/SIGNAL_NAMES=GRF+MASS_N
+/COMPONENT_SEQUENCE=Z, ALL
+/RESULT_NAME=GRF_R
+! /RESULT_FOLDER=PROCESSED
+;
+</code>
+<code>
+! Divide the result by body mass to get the vertical CoM acceleration
+Divide_Signals
+/SIGNAL_TYPES=DERIVED+METRIC
+/SIGNAL_FOLDER=PROCESSED
+/SIGNAL_NAMES=GRF_R+MASS
+/COMPONENT_SEQUENCE=ALL
+/RESULT_NAME=COM_GRF_Z_ACCEL
+! /RESULT_FOLDER=PROCESSED
+;
+!************************************************************
+! Integrate the vertical CoM acceleration over time to get the
+! change in vertical CoM velocity. Initial value is zero
+!***********************************************************
+Indefinite_Integral
+/SIGNAL_TYPES=DERIVED
+/SIGNAL_NAMES=COM_GRF_Z_ACCEL
+/SIGNAL_FOLDER=PROCESSED
+/RESULT_SUFFIX=_VEL
+! /RESULT_FOLDER=PROCESSED
+! /START_AT_EVENT=
+! /END_AT_EVENT=
+! /INITIAL_VALUE=0
+;
+</code>
+==== Legacy Parameters ====
+Earlier versions of Visual3D accepted the following parameters for this command. These parameters are no longer supported.
+<code>
+Indefinite_Integral
+/Signal_Types=The type of signal to be evaluated
+/Signal_Names=The name of the signal to be evaluated
+/Signal_Folder=The name of the signal folder
+/Result_Folder= The name of the resulting folder
+/Result_Suffix= The result is given the same name as the original signal with the suffix added
+/Start_At_Event= The event at the beginning of the range
+/End_At_Event= The event at the end of the range
+/Initial_Value= The value of the integral at the start event
+</code>