CSCI 240 Abstract Data Types

1
Department of Computer and Information
Science,School of Science, IUPUI
CSCI 240
Abstract Data Types
Sparse Matrices
Dale Roberts, Lecturer IUPUI droberts_at_cs.iupui.edu
2
Sparse Matrices
Sparse matrices have a large number of zero
elements in proportion to the number of nonzero
elements. Storing in n x n array will have a lot
of wasted space. Alternative circular lists
storing only nonzero elements.
3
Sparse Matrix Nodes
of head nodes of rows of columns
head node
entry node
tag
j
i
aij
aij
tag is used to tell entry, head and aij nodes part
4
Linked Representation for Matrix
4
4
0
2
11
1
1
1
0
12
5
1
2
-4
3
3
-15
Circular linked list
5
Sparse Matrix Data Structure

• define MAX_SIZE 50 / size of largest matrix
  /typedef enum head, entry tagfieldtypedef
  struct matrix_node matrix_pointertypedef
  struct entry_node int row
  int col int value
  typedef struct matrix_node
  matrix_pointer down matrix_pointer
  right tagfield tag
  union matrix_pointer
  next entry_node entry
  u
  matrix_pointer hdnodeMAX_SIZE

6
Try creating your data for this matrix
7
Acknowledgements

• All of this code is from Horowitz, Sahni, and
  Anderson-Freed, Fundamentals of Data Structures
  in C.
• Some slides were originally developed by Chen,
  Hsin-His.