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Topic: Creating matrix from another matrix using column position
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anton siswo

Posts: 2
From: Indonesia
Registered: 3/22/13
Creating matrix from another matrix using column position
Posted: Mar 24, 2013 11:23 PM
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Hello everyone here.....

I have problem here, I have a matrix 16x24, lets call it matrix A. There is Matrix B 24x24 which depend on the reading row and column with values from Matrix A.

Here are link for matrix A:

After that, I want to create matrix C, consist of matrix 150x150.

The rule are below here:

1. Matrix C formed from matrix A.
2. Each row and column from matrix C are read the values from matrix A for each row, not the entire matrix. If there is no values from matrix A (based on the tables) from each row from matrix A, such as A[1,100] then the value in C[1,100] is 0. For examples, row and column in matrix C [49,50] are formed from matrix A, for 49 in [8,1];[7,10];[4,13];[3,22] and for 50 in [8,2];[7,11];[4,14];[3,23]. I'm already using Position command in mathematica.
3. After that, get the column value only from matrix C for 49 and 50. It should be like this, for 49-> 1,10,13,22 and for 50 -> 2,11,14,23.
4. When we already got the column value for 49 and 50, we are forming the value from point 3 into [1,2];[10,11];[13,14];[22,23]. this 4 new elements are taking the value from matrix B in B[1,2];B[10,11];B[13,14];B[22,23].
5. After finished taking the value in matrix B, we sum it. So it should be sum of values from B[1,2] + B[10,11] + B[13,14] + B[22,23].
6. When finished, we take the result in matrix C. So, it should be C[49,50] = value from B[1,2] + B[10,11] + B[13,14] + B[22,23].
7. It goes along the way for matrix C starting from [1,1] until [150,150] using the rules before.

So, my question is how to implement it in mathematica? I'va been stuck for a month, because of this algorithm.

Thank you very much and I do sorry for my bad grammar.

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