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Integrate

LabWindows/CVI

Integrate

Advanced Analysis Library Only

AnalysisLibErrType Integrate (double inputArray[], ssize_t numberOfElements, double samplingInterval, double initialCondition, double finalCondition, double outputArray[]);

Purpose

Calculates the discrete integral of the input array Simpson's Rule for discrete evaluation. Integrate obtains the element of the resulting array using the following formula:

where X–1 is the initial condition
Xn is the final condition
i is the array index
n is the number of elements
dt is the sampling interval

The values are accumulated into the output array. Thus, the last element of the array contains the area under the curve.

Integrate can perform the operation in place; that is, the input and output arrays can be the same.

Example

/* Generate an array with random numbers and integrate it. */
double x[200], y[200];
double dt, xInit, xFinal;
int n;
n = 200;
dt = 0.001;
xInit = -0.5;
xFinal = -0.25;
Uniform (n, 17, x);
Integrate (x, n, dt, xInit, xFinal, y);

Parameters

Input
Name Type Description
inputArray double [] Input array to integrate.
numberOfElements ssize_t Number of elements used to compute the integral value of the input array.
samplingInterval double Sampling interval used in the integration.

Default Value: 1.0.
initialCondition double Initial condition.

When the integration formula is applied to each array element, the value of the preceding array element is used. initialCondition specifies the value preceding the first element of the input array. In other words, initialCondition can be thought of as the value of X–1.

Default Value: 0.0.
finalCondition double Final condition.

When the integration formula is applied to each array element, the value of the next array element is used. finalCondition specifies the value following the last element of the input array. In other words, finalCondition can be thought of as the value of Xn.

Default Value: 0.0.
Output
Name Type Description
outputArray double [] Integrated array.

Return Value

Name Type Description
status AnalysisLibErrType A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.

Additional Information

Library: Advanced Analysis Library

Include file: analysis.h

LabWindows/CVI compatibility: LabWindows/CVI 3.1 and later