constraints(VGAM)
constraints()所属R语言包：VGAM
Constraint Matrices
约束矩阵
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Extractor function for the constraint matrices of objects in the VGAM package.
提取VGAM的软件包中的对象的约束矩阵的函数。
用法----------Usage----------
constraints(object, ...)
参数----------Arguments----------
参数：object
Some VGAM object, for example, having class vglmff-class.
一些VGAM对象，例如，类vglmff-class。
参数：...
Other possible arguments such as type.
其他可能的参数，如type。
Details
详细信息----------Details----------
Constraint matrices describe the relationship of coefficients/component functions of a particular explanatory variable between the linear/additive predictors in VGLM/VGAM models. For example, they may be all different (constraint matrix is the identity matrix) or all the same (constraint matrix has one column and has unit values).
约束矩阵描述一个特定的解释变量之间的线性/添加剂预测在VGLM模型/ VGAM模型的系数/组件功能的关系。例如，它们可以是所有不同的（约束矩阵是单位矩阵）或所有相同的（约束矩阵具有一列，并具有单位值）。
VGLMs and VGAMs have constraint matrices which are known. The class of RR-VGLMs have constraint matrices which are unknown and are to be estimated.
VGLMs和VGAMs有约束矩阵，这是已知的。类的RR-VGLMs有约束矩阵的是未知的，要估算。
值----------Value----------
This extractor function returns a list comprising of constraint matrices—usually one for each column of the VLM model matrix, and in that order. The list is labelled with the variable names. Each constraint matrix has M rows, where M is the number of linear/additive predictors, and whose rank is equal to the number of columns. A model with no constraints at all has an order M identity matrix as each variable's constraint matrix.
该提取器函数返回一个约束矩阵，通常包括一个用于每个列的VLM模型矩阵的列表，并在该命令。被标记的变量名的列表。每个约束矩阵M行M是数量的线性/添加剂的预测，和的秩等于列数。在所有没有约束的命令M每个变量的约束矩阵单位矩阵作为模型。
For vglm and vgam objects, feeding in the "lm"-type constraint matrices back into the same model should work and give an identical model. The default are the "vlm"-type constraint matrices. See the constraints argument of vglm, and the example below.
vglm和vgam对象，喂养"lm"-type约束矩阵回相同的模型工作，并给出一个相同的模式。默认情况下是"vlm"型约束矩阵。请参阅constraints vglm参数，，下面的例子。
注意----------Note----------
In all VGAM family functions zero = NULL means none of the linear/additive predictors are modelled as intercepts-only. Other arguments found in certain VGAM family functions which affect constraint matrices include parallel and exchangeable.
在所有的VGAM的家庭功能zero = NULL是指没有线性/对添加剂的预测建模为拦截只。发现在某些VGAM约束矩阵的家庭功能影响的其他参数包括parallel和exchangeable。
The constraints argument in vglm and vgam allows constraint matrices to be inputted. If so, then constraints(fit, type = "lm") can be fed into the constraints argument of the same object to get the same model.
constraints参数vglm和vgam允许约束矩阵输入。如果是这样的话，那么constraints(fit, type = "lm")可以送入constraints同一个对象得到相同的模型参数。
The xij argument does not affect constraint matrices; rather, it allows each row of the constraint matrix to be multiplied by a specified vector.
xij参数不影响约束矩阵，而是允许约束矩阵的每一行的被指定的向量乘以。
（作者）----------Author(s)----------
T. W. Yee
参考文献----------References----------
Vector generalized additive models. Journal of the Royal Statistical Society, Series B, Methodological, 58, 481–493.
Reduced-rank vector generalized linear models. Statistical Modelling, 3, 15–41.
information.
参见----------See Also----------
VGLMs are described in vglm-class; RR-VGLMs are described in rrvglm-class.
VGLMs中描述vglm-class;的RR-VGLMs是在rrvglm-class。
Arguments such as zero and parallel found in many VGAM family functions are a way of creating/modifying constraint matrices conveniently, e.g., see zero. See CommonVGAMffArguments for more information.
如zero和parallel发现在许多VGAM家庭功能的参数是一个方便的创建/修改约束矩阵的方式，例如，看到zero。见CommonVGAMffArguments更多信息。
实例----------Examples----------
# Fit the proportional odds model:[适合的比例优势模型：]
pneumo <- transform(pneumo, let = log(exposure.time))
(fit1 <- vglm(cbind(normal, mild, severe) ~ bs(let, 3),
cumulative(parallel = TRUE, reverse = TRUE), pneumo))
coef(fit1, matrix = TRUE)
constraints(fit1) # Parallel assumption results in this[在此并行的假设结果]
constraints(fit1, type = "vlm") # This is the same as the default ("vlm"-type)[作为默认值，这是相同的（“VLM”型）]
# An equivalent model to fit1 (needs the type "lm" constraints):[的等效模型FIT1（需要类型“流明”的约束）：]
clist.lm <- constraints(fit1, type = "lm") # The "lm"-type constraints[“LM”型的限制]
(fit2 <- vglm(cbind(normal, mild, severe) ~ bs(let, 3),
cumulative(reverse = TRUE), pneumo, constraints = clist.lm))
abs(max(coef(fit1, matrix = TRUE) -
coef(fit2, matrix = TRUE))) # Should be zero[应该是零]
# Fit a rank-1 stereotype (RR-multinomial logit) model:[适合的职级-1型（RR-多项式logit）模型：]
data(car.all)
fit <- rrvglm(Country ~ Width + Height + HP, multinomial, car.all, Rank = 1)
constraints(fit) # All except the first are the estimated A matrix [除了第一个是估计的矩阵]
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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。
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发表于 2012-10-1 15:30:50
