modwt(waveslim)
modwt()所属R语言包:waveslim
(Inverse) Maximal Overlap Discrete Wavelet Transform
(反)最大重叠离散小波变换
译者:生物统计家园网 机器人LoveR
描述----------Description----------
This function performs a level J decomposition of the input vector using the non-decimated discrete wavelet transform. The inverse transform performs the reconstruction of a vector or time series from its maximal overlap discrete wavelet transform.
执行该功能的水平J分解的输入向量使用非抽取的离散小波转换。逆变换进行的矢量或从它的最大重叠离散小波变换的时间序列的重建。
用法----------Usage----------
imodwt(y)
参数----------Arguments----------
参数:x
a vector or time series containing the data be to decomposed. There is no restriction on its length.
的向量或包含数据的时间序列分解。其长度上是没有限制。
参数:y
Object of class "modwt".
对象类"modwt"。
参数:wf
Name of the wavelet filter to use in the decomposition. By default this is set to "la8", the Daubechies orthonormal compactly supported wavelet of length L=8 (Daubechies, 1992), least asymmetric family.
的小波滤波器的名称使用在分解。默认情况下,此设置为"la8"的Daubechies正交的紧支撑小波的长度L=8(Daubechies小,1992年),至少不对称的家庭。
参数:n.levels
Specifies the depth of the decomposition. This must be a number less than or equal to log(length(x),2).
指定的深度的分解。这必须是一个小于或等于log(length(x),2)。
参数:boundary
Character string specifying the boundary condition. If boundary=="periodic" the defaulTRUE, then the vector you decompose is assumed to be periodic on its defined interval,<br> if boundary=="reflection", the vector beyond its boundaries is assumed to be a symmetric reflection of itself.
字符串指定的边界条件。如果boundary=="periodic"defaulTRUE,然后在其定义的时间间隔,<br>请您分解的矢量假定是周期性的,则boundary=="reflection",超出其边界的矢量被假定为一个对称反射本身。
Details
详细信息----------Details----------
The code implements the one-dimensional non-decimated DWT using the pyramid algorithm. The actual transform is performed in C using pseudocode from Percival and Walden (2001). That means convolutions, not inner products, are used to apply the wavelet filters.
该代码实现的一维非锐减DWT使用金字塔算法。实际的转换工作是在C程序中使用的伪代码由波斯富街和Walden(2001)。这意味着卷积,而不是内积,用于应用小波滤波器。
The MODWT goes by several names in the statistical and engineering literature, such as, the “stationary DWT”, “translation-invariant DWT”, and “time-invariant DWT”.
MODWT“的统计和工程文献的几个名字,如”静止载重吨“,”平移不变性的DWT“,”时间不变载重吨“。
The inverse MODWT implements the one-dimensional inverse transform using the pyramid algorithm (Mallat, 1989).
逆MODWT实现的一维逆变换使用金字塔算法(Mallat的,1989年)。
值----------Value----------
Object of class "modwt", basically, a list with the following components
对象的类"modwt",基本上,一个列表,以下组件
参数:d?
Wavelet coefficient vectors.
小波系数向量。
参数:s?
Scaling coefficient vector.
缩放系数向量。
参数:wavelet
Name of the wavelet filter used.
小波滤波器的名称。
参数:boundary
How the boundaries were handled.
的界限如何处理。
(作者)----------Author(s)----------
B. Whitcher
参考文献----------References----------
An Introduction to Wavelets and Other Filtering Methods in Finance and Economics, Academic Press.
Long-memory processes, the Allan variance and wavelets, In Wavelets and Geophysics, pages 325-344, Academic Press.
Wavelet Methods for Time Series Analysis, Cambridge University Press.
参见----------See Also----------
dwt, idwt, mra.
dwt,idwt,mra。
实例----------Examples----------
## Figure 4.23 in Gencay, Selcuk and Whitcher (2001)[#图4.23 Gencay,塞尔丘克和Whitcher的(2001年)]
data(ibm)
ibm.returns <- diff(log(ibm))
# Haar[哈尔]
ibmr.haar <- modwt(ibm.returns, "haar")
names(ibmr.haar) <- c("w1", "w2", "w3", "w4", "v4")
# LA(8)[LA(8)]
ibmr.la8 <- modwt(ibm.returns, "la8")
names(ibmr.la8) <- c("w1", "w2", "w3", "w4", "v4")
# shift the MODWT vectors[转移MODWT向量]
ibmr.la8 <- phase.shift(ibmr.la8, "la8")
## plot partial MODWT for IBM data[#图部分MODWT的为IBM数据]
par(mfcol=c(6,1), pty="m", mar=c(5-2,4,4-2,2))
plot.ts(ibm.returns, axes=FALSE, ylab="", main="(a)")
for(i in 1:5)
plot.ts(ibmr.haar[[i]], axes=FALSE, ylab=names(ibmr.haar)[i])
axis(side=1, at=seq(0,368,by=23),
labels=c(0,"",46,"",92,"",138,"",184,"",230,"",276,"",322,"",368))
par(mfcol=c(6,1), pty="m", mar=c(5-2,4,4-2,2))
plot.ts(ibm.returns, axes=FALSE, ylab="", main="(b)")
for(i in 1:5)
plot.ts(ibmr.la8[[i]], axes=FALSE, ylab=names(ibmr.la8)[i])
axis(side=1, at=seq(0,368,by=23),
labels=c(0,"",46,"",92,"",138,"",184,"",230,"",276,"",322,"",368))
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注:
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