How can I fix the error "Index exceeds matrix dimension"

In my FEM program, I want to build a matrix bcdof[1;2;7;8;67;68;69;70;71;72] from matrix bcdof1=[1;4;34;35;36] but the program say that "Index exceeds matrix dimension". Can anyone help me, here is my code:

bcdof1=[1;4;34;35;36];
bcdof=zeros(1,2*length(bcdof1));
for i=1:length(bcdof1)
    bcdof(1,(2*i-1))=2*bcdof1(1,i)-1;
    bcdof(1,(2*i))=2*bcdof1(1,i);
end

[madhan ravi]

You have to explain the calculation

[Ductho Le]

the calculation was in my code, each element in matrix bcdof have a corresponding value in the right hand side.

Answer 1

[Dennis]

bcdof1 is a column vector you need to index bcdof1(i,1) instead of bcdof(1,i)

bcdof1=[1;4;34;35;36];
bcdof=zeros(1,2*length(bcdof1));
for i=1:length(bcdof1)
    bcdof(1,(2*i-1))=2*bcdof1(i,1)-1;
    bcdof(1,(2*i))=2*bcdof1(i,1);
end

[Ductho Le]

thank you man..I'm forgot this:))

Answer 2

[KALYAN ACHARJYA]

bcdof1=[1;4;34;35;36];
bcdof=zeros(1,2*length(bcdof1));
for i=1:1 %length(bcdof1)
    bcdof(1,2*i-1)=2*bcdof1(1,i)-1;
    bcdof(1,2*i)=2*bcdof1(1,i);
end

Your matrix is size 5x1, there is a single column. What you are doing a here using "for loop" from 1 to 5.

when i=1, it is ok, but when i=1, in your following expression

bcdof(1,2*i-1)=2*bcdof1(1,i)-1;

becomes

bcdof(1,3)=2*bcdof1(1,2)-1;

That means bcdof(1,3) and bcdof1(1,2) data is not available in matrix.

As your following data having only

bcdof1=[1;4;34;35;36];

That means

bcdof1(1,1)=1;
bcdof1(2,1)=4;
bcdof1(3,1)=34;

Please note the differences

 bcdof1=[1;4;34;35;36]

bcdof1 =

       1
       4
      34
      35
      36

>> bcdof1=[1,4,34,35,36]

bcdof1 =

       1     4    34    35    36

[KALYAN ACHARJYA]

bcdof1=[1;4;34;35;36];
bcdof=zeros(1,2*length(bcdof1));
for i=1: 1    %length(bcdof1) for sinle 1 its works
    bcdof(1,2*i-1)=2*bcdof1(1,i)-1;
    bcdof(1,2*i)=2*bcdof1(1,i);
end

Another one if you change the column vector to row vector then it works

bcdof1=[1,4,34,35,36]; % Change the data column to row matrix
bcdof=zeros(1,2*length(bcdof1));
for i=1:1%length(bcdof1)
    bcdof(1,2*i-1)=2*bcdof1(1,i)-1;
    bcdof(1,2*i)=2*bcdof1(1,i);
end

[Ductho Le]

thank you..i have seen that problem.

[KALYAN ACHARJYA]

Third way to avoid the error is- % Index position change from bcdof1(1,i) to bcdof1(i,1)

bcdof1=[1;4;34;35;36];
bcdof=zeros(1,2*length(bcdof1));
for i=1:1%length(bcdof1)
    bcdof(1,2*i-1)=2*bcdof1(i,1)-1; 
    bcdof(1,2*i)=2*bcdof1(i,1);
end