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1. Advanced Data Structure using C++

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LECTURE NOTES OF ADVANCED DATA STRUCTURE (MT-CSE 110)<br />

AD and LA. Using the above convention for numbering the<br />

diagonals, and given that sparse matrix A contains nd diagonals<br />

having nonzero elements, arrays AD and LA are set up as follows:<br />

• AD is defined as AD(lda,nd), where the leading dimension,<br />

lda, must be greater than or equal to n. Each diagonal of<br />

matrix A that has at least one nonzero element is stored in a<br />

column of array AD. All of the elements of the diagonal,<br />

including its zero elements, are stored in n contiguous<br />

locations in the array, in the same order as they appear in<br />

the diagonal. Padding with zeros is required as follows to fill<br />

the n locations in each column of array AD:<br />

o Each superdiagonal (k > 0), which has n‐k elements, is<br />

padded with k trailing zeros.<br />

o The main diagonal (k = 0), which has n elements, does<br />

not require padding.<br />

o Each subdiagonal (k < 0), which has n‐|k| elements, is<br />

padded with |k| leading zeros.<br />

• LA is a one‐dimensional integer array of length nd, containing<br />

the diagonal numbers k for the diagonals stored in each<br />

corresponding column in array AD.<br />

3. Storage‐by‐Indices<br />

For a sparse matrix A, storage‐by‐indices uses three one‐<br />

dimensional arrays to define the sparse matrix storage, AR, IA, and<br />

JA. Given the m by n sparse matrix A having ne nonzero elements,<br />

the arrays are set up as follows:<br />

• AR of (at least) length ne contains the ne nonzero elements of<br />

the sparse matrix A, stored contiguously in any order.<br />

• IA, an integer array of (at least) length ne contains the<br />

Prepared By :­<br />

Er. Harvinder Singh<br />

Assist Prof., CSE, H.C.T.M (Kaithal) Page ‐ 129 ‐

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