Assembly: ImslCS (in ImslCS.dll) Version: 6.5.0.0
Syntax
C# |
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[SerializableAttribute] public class Difference |
Visual Basic (Declaration) |
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<SerializableAttribute> _ Public Class Difference |
Visual C++ |
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[SerializableAttribute] public ref class Difference |
Remarks
Class Difference performs m = periods.Length successive backward differences of period and order on the n = z.Length observations .
Consider the backward shift operator B given by
for all k. Then, the backward difference operator with period s is defined by the following:
Note that and are defined only for . Repeated differencing with period s is simply
where is the order of differencing. Note that
is defined only for .
The general difference formula used in the class Difference is given by
where represents the number of observations "lost" because of differencing and NaN represents the missing value code. Note that
A homogeneous, stationary time series can be arrived at by appropriately differencing a homogeneous, nonstationary time series (Box and Jenkins 1976, p. 85). Preliminary application of an appropriate transformation followed by differencing of a series can enable model identification and parameter estimation in the class of homogeneous stationary autoregressive moving average models.