如何构建一个包含9个较小矩阵的矩阵 [英] How to construct a matrix containing 9 smaller matrix
问题描述
A1(i,j),A2(i,j),A3(i,j),A4(i, j),A5(i,j),A6(i,j),A7(i,j),A8(i,j),A9(i,j)
$ b
然后我想构造一个更大的矩阵(3N乘3N),包括这9个矩阵:
A = [A1 A2 A3
A4 A5 A6
A7 A8 A9]
<在Fortran中,我可以使用命令行:
do i = 1,FN
do j = 1 ,A(i,j)= A 1(i,j),A 2(i,j),A 3(i,j) (i,j); A7(i,j),A8(i,j),A9(i,j)]
end do
end do
解决方案为了好玩,您还可以通过使用do循环来制作大型A矩阵。
do i = 1,N
A(i,:)= [A1(i ,:),A2(i ,: ),A3(i ,:)]
A(i + N,:)= [A4(i ,:),A5(i ,:),A6(i ,:)]
A i + N * 2,:)= [A7(i ,:),A8(i ,:),A9(i ,:)]
enddo
其中fi以行为主方式排列A矩阵,所以小矩阵也以这种方式出现。如果确实需要的话,这也可以写成一行:
A =转置(重塑(&
([A1(i ,:),A2(i ,:),A3(i ,:)],i = 1,N),&
A8(i ,:),A9(i ,:)],A6(i ,:)],i = 1,N),&
i = 1,N)],[N * 3,N * 3]))
A = reshape(在一行中) &
[([A1(:,i),A4(:,i),A7(:,i)],i = 1,N) (:,i),A5(:,i),A8(:i)],i = 1,N),
,i = 1,N)],[N * 3,N * 3])
< hr>
为了更进一步,我们可以定义
hcat
和vcat
例程与其他语言一样(注意这里需要显式接口):
funct (A,B,C)result(X)
integer,dimension(:, :) :) A,B,C
integer :: X(size(A,1),size( A,2)+尺寸(B,2)+尺寸(C,2))
X =重塑([A,B,C],形状(X))
endfunction
函数vcat(A,B,C)结果(X)
整数,维(:, :) :: A,B,C
integer :: X(size( A,1)+大小(B,1)+大小(C,1),大小(A,2))
X =转置(重塑(&
[转置(A),转置(B),转置(C)],&
[size(X,2),size(X,1)]))
endfunction
$ p
$ $ $ code $ A = vcat(hcat(A1,A2,A3),hcat(A4, A5,A6),hcat(A7,A8,A9))
在问题中需要的形式:
A = [A1 A2 A3; A4 A5 A6; A7 A8 A9]
I have nine matrices whose dimension as (N by N)
A1(i,j),A2(i,j),A3(i,j),A4(i,j),A5(i,j),A6(i,j),A7(i,j),A8(i,j),A9(i,j)
Then I want to construct a larger matrix (3N by 3N) including these nine matrices as:
A = [A1 A2 A3
A4 A5 A6
A7 A8 A9]
In fortran, can I use the command line as
do i=1,FN
do j=1,FML
A(i,j) = [A1(i,j),A2(i,j),A3(i,j);A4(i,j),A5(i,j),A6(i,j);A7(i,j),A8(i,j),A9(i,j)]
end do
end do
Just for fun, you can also make the large A matrix by using do-loops as
do i = 1, N
A( i, : ) = [ A1( i,: ), A2( i,: ), A3( i,: ) ]
A( i + N, : ) = [ A4( i,: ), A5( i,: ), A6( i,: ) ]
A( i + N*2, : ) = [ A7( i,: ), A8( i,: ), A9( i,: ) ]
enddo
which fills the A matrix in row-major way and so the small matrices also appear in that way. If really really necessary, this could also be written as one-liner as
A = transpose( reshape( &
[ ( [ A1( i,: ), A2( i,: ), A3( i,: ) ], i=1,N ), &
( [ A4( i,: ), A5( i,: ), A6( i,: ) ], i=1,N ), &
( [ A7( i,: ), A8( i,: ), A9( i,: ) ], i=1,N ) ], [N*3, N*3] ))
which turns out to be the transpose of the second array constructor in the @francescalus answer (in one-liner form)
A = reshape( &
[ ( [ A1( :,i ), A4( :,i ), A7( :,i ) ], i=1,N ), &
( [ A2( :,i ), A5( :,i ), A8( :,i ) ], i=1,N ), &
( [ A3( :,i ), A6( :,i ), A9( :,i ) ], i=1,N ) ], [N*3, N*3] )
To go one-step further, we may define hcat
and vcat
routines as in other languages (note here that explicit interface is necessary):
function hcat( A, B, C ) result( X )
integer, dimension(:,:) :: A, B, C
integer :: X( size(A,1), size(A,2)+size(B,2)+size(C,2) )
X = reshape( [ A, B, C ], shape( X ) )
endfunction
function vcat( A, B, C ) result( X )
integer, dimension(:,:) :: A, B, C
integer :: X( size(A,1)+size(B,1)+size(C,1), size(A,2) )
X = transpose( reshape( &
[ transpose(A), transpose(B), transpose(C) ], &
[ size(X,2), size(X,1) ] ) )
endfunction
then we can write
A = vcat( hcat( A1, A2, A3 ), hcat( A4, A5, A6 ), hcat( A7, A8, A9 ) )
which is somewhat more similar to the desired form in the question:
A = [ A1 A2 A3 ; A4 A5 A6 ; A7 A8 A9 ]
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