mfirst.last(wavethresh)
mfirst.last()所属R语言包：wavethresh
Build a first/last database for multiple wavelet transforms.
建立一个多小波变换的第一个/最后一个数据库。
译者：生物统计家园网 机器人LoveR
描述----------Description----------
This function is not intended for user use, but is used by various functions involved in computing and displaying multiple wavelet transforms.
此功能供用户使用，而是用来计算和显示多个小波变换的各种功能。
用法----------Usage----------
mfirst.last(LengthH, nlevels, ndecim, type = "wavelet", bc = "periodic")
参数----------Arguments----------
参数：LengthH
Number of filter matrix coefficients.
滤波器矩阵系数的数目。
参数：nlevels
Number of levels in the decomposition
在分解中的级别数
参数：ndecim
The decimation scale factor for the multiple wavelet basis.
抽取比例因子为多个小波基。
参数：type
Whether the transform is non-decimated or ordinary (wavelet). The non-decimated multiple wavelet transform is not yet supported.
无论是变换是不可毁灭或普通股（小波）。目前还不支持非锐减的多小波变换。
参数：bc
This argument determines how the boundaries of the the function are to be handled. The permitted values are periodic or symmetric
此参数确定的界限的功能是如何处理的。允许的值是定期或symmetric
Details
详细信息----------Details----------
Suppose you begin with 2^m=2048 coefficient vectors. At the next level you would expect 1024 smoothed data vectors, and 1024 wavelet vectors, and if bc="periodic" this is indeed what happens. However, if bc="symmetric" you actually need more than 1024 (as the wavelets extend over the edges). The first last database keeps track of where all these "extras" appear and also where they are located in the packed vectors C and D of pyramidal coefficients within wavelet structures.
假设你开始2^m= 2048系数向量。在一个新的水平，你所期望的1024个平滑的数据向量，和1024小波向量，如果bc="periodic"这确实是发生了什么。但是，如果bc="symmetric"你的实际需要超过1024个（如小波扩展到边缘）。倒数第一的数据库跟踪，所有这些“额外”的出现，它们的位置在拥挤的向量C和D的金字塔系数在小波结构。
For examples, given a first.last.c row of
举例来说，一个first.last.c行
The "position" of the coefficient vectors would be
“位置”的系数向量
In other words, there are 6 coefficients, starting at -2 and ending at 3, and the first of these (c_{-2}) appears at column 20 of the $C component matrix of the wavelet structure.
换句话说，有6个系数，在-2开始和结束于3，这些和第一（c_{-2}）出现在塔20$C分量矩阵的小波结构。
You can “do” first.last in your head for periodic boundary handling but for more general boundary treatments (e.g. symmetric) first.last is indispensable.
您可以在“做”first.last在你的脑袋周期性边界处理，但更一般的边界处理（例如对称）first.last是不可缺少的。
The numbers in first last databases were worked out from inequalities derived from: Daubechies, I. (1988).
在倒数第一的数据库的数字计算出来的不平等来自的Daubechies小，I.（1988）。
值----------Value----------
A first/last database structure, a list containing the following information:
第一个/最后的数据库结构，一个列表，其中包含以下信息：
<table summary="R valueblock"> <tr valign="top"><td>first.last.c</td> <td> A (m+1)x3 matrix. The first column specifies the real index of the first coefficient vector of the smoothed data at a level, the 2nd column is the real index of the last coefficient vector, the last column specifies the offset of the first smoothed datum at that level. The offset is used by the C code to work out where the beginning of the sequence is within a packed vector of the pyramid structure. The first and 2nd columns can be used to work out how many numbers there are at a level. If bc="periodic" then the pyramid is a true power of 2 pyramid, that is it starts with a power of 2, and the next level is half of the previous. If bc="symmetric" then the pyramid is nearly exactly a power of 2, but not quite, see the Details section for why this is so.</td></tr> <tr valign="top"><td>nvecs.c</td> <td> The number of C coefficient vectors.</td></tr> <tr valign="top"><td>first.last.d</td> <td> A mx3 matrix. As for first.last.c but for the wavelet coefficients packed as the D component of a wavelet structure.</td></tr> <tr valign="top"><td>nvecs.d</td> <td> The number of D coefficient vectors.</td></tr> </table>
<table summary="R valueblock"> <tr valign="top"> <TD> first.last.c</ TD> <TD> A(m+1)x3矩阵。第一列指定真实的指数在一个水平的平滑化数据的第一系数的矢量，第2列是真正的最后系数矢量的指数，指定的偏移量，在该水平的第一被平滑的数据的最后一列。偏移量所使用的C代码的工作，满分该从哪里开始的序列内的金字塔结构的填充矢量。可用于工作的第一列和第二列有多少个数字的水平。如果BC =“定期”，那么金字塔金字塔，是一个真正的力量，开始的2的幂，一个新的水平是以前的一半。如果BC =“对称”，那么金字塔几乎完全是2的幂，但不太详细信息，请参阅“一节，为什么会是这样。</ TD> </ TR> <tr valign="top"> <TD> nvecs.c</ TD> <TD>的C系数向量的数量。</ TD> </ TR> <tr valign="top"> <TD>first.last.d</ TD> <TD> Amx3矩阵。至于first.last.c，但对于包装的D分量的小波结构的小波系数。</ TD> </ TR> <tr valign="top"> <TD> nvecs.d</ TD> <TD>D系数向量。</ TD> </ TR> </表>
RELEASE----------RELEASE----------
Version 3.9.6 (Although Copyright Tim Downie 1995-6)
版本3.9.6（虽然版权蒂姆·唐尼1995-96）
（作者）----------Author(s)----------
Tim Downie
参见----------See Also----------
accessC.mwd, accessD.mwd, draw.mwd, mwd.object, mwd, mwr, plot.mwd, print.mwd, putC.mwd, putD.mwd, summary.mwd, threshold.mwd, wd, wr.mwd.
accessC.mwd，accessD.mwd，draw.mwd，mwd.object，mwd，mwr，plot.mwd，print.mwd，putC.mwd，putD.mwd，summary.mwd，threshold.mwd，wd，wr.mwd。
实例----------Examples----------
#[]
#To see the housekeeping variables for a decomposition with[要查看家政变量的分解与]
# 4 filter coefficient matices[过滤器系数matices 4]
# 5 resolution levels and a decimation scale of two[5分辨率和抽取两个规模]
# use:[使用方法：]
mfirst.last(4,5,2)
# $first.last.c:[$ first.last.c：]
# First Last Offset[尾页偏移]
# [1,] 0 0 62[[1] 0 0 62]
# [2,] 0 1 60[[2] 0 1 60]
# [3,] 0 3 56[[3] 0 3 56]
# [4,] 0 7 48[[4] 0 7 48]
# [5,] 0 15 32[[5] 0 15 32]
# [6,] 0 31 0[[6] 0 31 0]
# []
# $nvecs.c:[$ nvecs.c：]
# [1] 63[[1] 63]
# []
# $first.last.d:[$ first.last.d：]
# First Last Offset[尾页偏移]
# [1,] 0 0 30[[1，] 0 0 30]
# [2,] 0 1 28[[2] 0 1月28日]
# [3,] 0 3 24[[3] 3月24日]
# [4,] 0 7 16[[4] 7月16日]
# [5,] 0 15 0[[5] 0 15 0]
# []
# $nvecs.d:[$ nvecs.d：]
# [1] 31[[1] 31]
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-10-1 17:26:42
