replace part of matrix to another matrix

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mohammed hussein
mohammed hussein 2017-11-18
评论： mohammed hussein 2017-11-19
Hi i have many matrices in same size , i want to add all of them together in one matrix with replace the last quarter of each one to binning of next one until complete the matrix and the rest will be zeros . for example
a =zeros(5,5)
A=[1 2 ;3 4];
B=[5 6;7 8];
C=[9 10;11 12];
D=[13 14;15 16];
the answer
a=
1 2 0 0 0
3 5 6 0 0
0 7 9 10 0
0 0 11 13 14
0 0 0 15 16
thank you very much for helping

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采纳的回答

Stephen23
Stephen23 2017-11-18
编辑：Stephen23 2017-11-18
For any size matrices, even combinations of different sizes:
C = {[1,2;3,4],[5,6;7,8],[9,10;11,12],[13,14;15,16]};
num = numel(C);
szr = cellfun('size',C,1);
szc = cellfun('size',C,2);
csr = cumsum([0,szr-1]);
csc = cumsum([0,szc-1]);
M = zeros(1+csr(end),1+csc(end));
for k = 1:num
idr = csr(k)+(1:szr(k));
idc = csc(k)+(1:szc(k));
M(idr,idc) = C{k};
end
Giving:
>> M
M =
1 2 0 0 0
3 5 6 0 0
0 7 9 10 0
0 0 11 13 14
0 0 0 15 16
It works perfectly with any size matrices, e.g.:
C = {[1,2;3,4],[5,6;7,8],[1,2,3;4,5,6;7,8,9],[9,10;11,12],[13,14;15,16]};
gives
M =
1 2 0 0 0 0 0
3 5 6 0 0 0 0
0 7 1 2 3 0 0
0 0 4 5 6 0 0
0 0 7 8 9 10 0
0 0 0 0 11 13 14
0 0 0 0 0 15 16

更多回答（2 个）

Walter Roberson
Walter Roberson 2017-11-18
A=[1 2 ;3 4];
B=[5 6;7 8];
C=[9 10;11 12];
D=[13 14;15 16];
newvals = {A, B, C, D};
a = zeros(5,5);
for K = 1 : length(newvals)
a(K:K+1, K:K+1) = newvals{K};
end
Andrei Bobrov
Andrei Bobrov 2017-11-18
编辑：Andrei Bobrov 2017-11-18
In your case (without loop)
k = cat(3,A,B,D,C);
[m,n,q] = size(k);
a = full(gallery('tridiag',q*m/2+1,1,1,1));
ii = ((1:m*n-1) + (0:q-1)'*m*n)';
a(a>0) = k([ii(:);prod([m,n,q])]);
in general case (with for..end loop)
C = {[1,2;3,4],[5,6;7,8],[1,2,3;4,5,6],[9,10;11,12],[13,14;15,16]};
[m,n] = cellfun(@(x)size(x),C(:));
s = sum(m-1) + 1;
a = zeros(s,sum(n-1)+1);
jj = 1;
for ii = 1:numel(m)
id = jj + (0:m(ii)-1)' + s*(0:n(ii)-1);
a(id) = C{ii};
jj = id(end);
end
All for MATLAB >= R2016b

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