2012-12-03 55 views
3

matlab中的代码是为了使生态系统中的物种在生态系统中丢失而发挥作用的可能性而创建的。现在,这段代码必须翻译成R.但是我有翻译matlab中进行的矩阵操作的问题。将matlab代码中的矩阵转换为R代码

在Matlab中,这是我试图转换成R代码代码:

for j=1:N+1 
multi_matrix4(:,j)=matrix(:,1); 
end 

在R,我已经把这个代码中的for循环:

+ multi.matrix4 <- matrix[,1,drop=FALSE] 
+ multi.matrix4 <- multi.matrix4[,j,drop=FALSE] 
+ class(multi.matrix4) 

这是从R中的信息,附带下方的for循环:

Error: subscript out of bounds 

我的问题是: 如何使用R进行这种矩阵操作??????

没有最后图表中的MATLAB代码是:

clear all 

% No of permutations 
sim=1000; 

% Total No of ecosystem functions  
N=3; 

%Total dimensions 
J=3; 

% Total No of species in pool 
total_species=4; 

% No of species drawn from pool 
species=4; 
multi_matrix=zeros(total_species,N); 

% "Threshold" 
t=.5; 

result=zeros(sim,J); 

for i=1:sim 

% %Uniformly increasing trait values 
for j=1:N 
matrix=rand(total_species,2); 
matrix(:,1)=linspace(0,1,total_species); 
matrix=sortrows(matrix,2); 
multi_matrix4(:,j)=matrix(:,1); 
end 

%Complete covariance 
matrix=rand(total_species,2); 
matrix(:,1)=linspace(0,1,total_species); 
matrix=sortrows(matrix,2); 
for j=1:N+1 
multi_matrix4(:,j)=matrix(:,1); 
end 

% Excess of high trait values 
for j=1:N 
matrix=rand(total_species,2); 
X=1:total_species;X=X'; 
matrix(:,1)=1-exp(-0.02*X.^2); 
matrix=sortrows(matrix,2); 
multi_matrix4(:,j)=matrix(:,1); 
end 


% Deficiency of high trait values 
for j=1:N 
matrix=rand(total_species,2); 
X=1:total_species;X=X'; 
% matrix(:,1)=exp((X./22.6).^3)-1; 
matrix(:,1)=exp((X./13.55).^3)-1; 
matrix=sortrows(matrix,2); 
multi_matrix4(:,j)=matrix(:,1); 
end 


% Reading empirical data 
warning off 
% [NUMERIC,txt]=xlsread('Plant_6.xls','Sheet1'); 
Exp07_2 = [ 0 0.72 0.70 ; 1 1 0 ; 0.62 0 1 ; 0.36 0.69 0.61] 
multi_matrix(1:total_species,1:N)=Exp07_2; 
random=rand(1,N); 
multi_matrix(total_species+1,1:N)=random; 
multi_matrix2=sortrows(multi_matrix',total_species+1); 
multi_matrix3=multi_matrix2'; 
multi_matrix4=multi_matrix3(1:total_species,:); 
warning on 


    % adding a sorting column 
    random2=rand(total_species,1); 
    multi_matrix4(:,N+1)=random2; 
    sort_multi_matrix=sortrows(multi_matrix4,N+1); 

    % loop adding one function at a time 
    for j=1:J 

     loss_matrix=sort_multi_matrix(1:species,1:j); 
     max_value=loss_matrix>=t; 
     B=any(max_value',2); 
     C=all(B); 
     result(i,j)=sum(C); 

    end 

end 

% reporting 
res=mean(result); 
res' 

的R-代码如下所示:

rm() 

#No of permutation 
sims <- 1000; 

#Total number of ecosystem functions 
N <- 3 

#Total dimensions 
J <- 3 

#Total number of species in pool 
total.species <- 4 

#No of species drawn from pool 
species <- 4 

multi.matrix <- matrix(0, nrow=total.species, ncol=N) 
class(multi.matrix) 

# $Threshold$ 
t <- .5; 

# The results are to be put in a matrix 
result <- matrix(0, nrow=sims, ncol=J) 

for (i in 1 : sims) 
{ 

#Uniformly increasing trait values 
for (j in 1 : N) 
{ 
matrix <- matrix(runif(total.species*2),total.species) 
class(matrix) 
matrix[,1] <- seq(0,1, len=total.species) # test 2 
class(matrix) 
matrix <- matrix[order(matrix(,2)),] 
class(matrix) 
# multi.matrix4[,j,drop=FALSE] = matrix[,1,drop=FALSE] 
multi.matrix4 <- matrix[,1,drop=FALSE] 
multi.matrix4 <- multi.matrix4[,j,drop=FALSE] 
class(multi.matrix4) 
} 

# Complete covariance 
matrix <- matrix(runif(total.species*2),total.species) 
class(matrix) 
matrix[,1] <- seq(0, 1, len=total.species) 
class(matrix) 
matrix <- matrix[order(matrix(,2)),] 
class(matrix) 
for (j in 1 : N + 1) 
{multi.matrix4 <- matrix[,1,drop=FALSE] 
multi.matrix4 <- multi.matrix4[,j,drop=FALSE] 
class(multi.matrix4) 
} 

# Excess of high trait values 
for (j in 1 : N) 
{matrix <- matrix(runif(total.species*2),total.species) 
class(matrix) 
X <- 1 : total.species 
X <- t(X) 
matrix[,1] <- c(1 - exp(-0.02 %*% X^2)) # Hie... p. 8 
matrix <- matrix[order(matrix(,2)),] 
# multi.matrix4[,j,drop=FALSE] <- matrix[,1,drop=FALSE] 
# multi.matrix4[,j,drop=FALSE] <- matrix[,1] 
multi.matrix4 <- matrix[,1,drop=FALSE] 
multi.matrix4 <- multi.matrix4[,j,drop=FALSE] 
class(multi.matrix4) 
} 

# Deficiency of high trait values 
for (j in 1 : N) 
{matrix <- matrix(runif(total.species*2),total.species) 
    class(matrix) 
X <- 1 : total.species 
X <- t(X) 
# matrix[1:4,1] <- c(exp((X/22.6)^3)-1) 
matrix[1:4,1] <- c(exp((X/13.55)^3)-1) 
class(matrix) 
matrix <- matrix[order(matrix(,2))] 
class(matrix) 
# multi.matrix4[,j,drop=FALSE] <- matrix[,1,drop=FALSE] 
# multi.matrix4[,j,drop=FALSE] <- matrix[,1] 
# multi.matrix4[,j] <- matrix[,1,drop=FALSE] 
# class(multi.matrix4) 
multi.matrix4 <- matrix[,1,drop=FALSE] 
multi.matrix4 <- multi.matrix4[,j,drop=FALSE] 
class(multi.matrix4) 
} 

# Reading empirical data 
Exp_07_2 <- file(description = "Exp_07_2", open = "r", blocking = TRUE, encoding = getOption("encoding"), raw = FALSE) 
Exp_07_2 <- matrix(scan(Exp_07_2),nrow=4,byrow=TRUE) 
read.matrix <- function(Exp_07_2){ 
    as.matrix(read.table(Exp_07_2)) 
} 
Exp_07_2 
class(Exp_07_2) 
multi.matrix <- matrix(c(Exp_07_2),ncol=3) 
class(multi.matrix) 
multi.matrix <- multi.matrix(1:total.species,1:N) 
class(multi.matrix) 
random <- runif(N) 
multi.matrix2 <- t(multi.matrix)[order(t(multi.matrix)[,1], t(multi.matrix)[,2], t(multi.matrix)[,3], t(multi.matrix)[,4]),] 
class(multi.matrix2) 
multi.matrix3 <- t(multi.matrix2) 
class(multi.matrix3) 
multi.matrix4 <- multi.matrix3[1:total.species,,drop=FALSE] 
class(multi.matrix4) 


# Adding a sorting column 
random2 <- runif(total.species,1) 
random2 <- multi.matrix4[,N+1,drop=FALSE] 
sort.multi.matrix <- multi.matrix4(order(multi.matrix4[,1], multi.matrix4[,2], multi.matrix4[,3],multi.matrix4[,4]),N+1,drop=FALSE) 

# loop adding one function at a time 
for (j in 1 : J) 

{loss.matrix <- sort.multi.matrix[nrow=species,ncol=j,drop=FALSE] 
    class(loss.matrix) 
max.value <- loss.matrix >= t 
c(B) <- any(t(max.value),2) 
c(C) <- all(c(B)) 
result(i,j) <- c(sum(C)) 
} 
} 

# Reporting 
res <- mean(result) 
res 
t(res) 
+0

你可以翻译成'just R',或者你可以翻译成[Armadillo](http://arma.sf.net),它可以通过[RcppArmadillo](http://dirk.eddelbuettel)从R中使用。 COM /代码/ rcpp.armadillo.html)。 Armadillo的设计目标之一是为Matlab用户提供这种类型的转换。我已经完成了昂贵的仿真问题,取得了巨大的成功,并且获得了非常显着的速度提升。 –

+0

也许如果你用'for'循环发布R代码,我们可以帮助你更好一点。只是猜测,但我怀疑'multi.matrix4'中只有'N'列,并且当'j'命中'N + 1'时循环失败。 – nograpes

+0

是的,这是正确的。现在,R代码已发布。 – user1842171

回答

0

虽然我没有Matlab的和R在手,让我怀疑这是什么造成的问题:

在R您尝试分配给矩阵中不存在的位置,结果:它失败

在Matlab中,您尝试将其分配给矩阵中不存在的位置,结果是:它会原谅您的奇怪选择,扩展您的矩阵并成功。

假设这就是问题所在,解决方法很简单:

当创建R中的矩阵,确保它是足够大的 包含所有你想在以后添加到它的东西。

这被称为initalization,并且在大多数情况下是最佳实践。即使在Matlab中,通常建议尽可能提前初始化变量,然后让它们随着时间增长。

+0

谢谢。然后我将初始化代码,使矩阵成正比。这说得通。 – user1842171