Logo 
Search:

C Programming Articles

Submit Article
Home » Articles » C Programming » Mathematics ProgramRSS Feeds

Program to multiply two sparse matrices

Posted By: Elizabeth Hughes     Category: C Programming     Views: 19632

Program to multiply two sparse matrices.

Code for Program to multiply two sparse matrices in C Programming

#include <stdio.h>
#include <conio.h>
#include <alloc.h>

#define MAX1 3
#define MAX2 3
#define MAXSIZE 20

#define TRUE 1
#define FALSE 2

struct sparse
{
    int *sp ;
    int row ;
    int *result ;
} ;

void initsparse ( struct sparse * ) ;
void create_array ( struct sparse * ) ;
int count ( struct sparse ) ;
void display ( struct sparse ) ;
void create_tuple ( struct sparse*, struct sparse ) ;
void display_tuple ( struct sparse ) ;
void prodmat ( struct sparse *, struct sparse, struct sparse ) ;
void searchina ( int *sp, int ii, int*p, int*flag ) ;
void searchinb ( int *sp, int jj, int colofa, int*p, int*flag ) ;
void display_result ( struct sparse ) ;
void delsparse ( struct sparse * ) ;

void main( )
{
    struct sparse s[5] ;
    int i ;

    clrscr( ) ;

    for ( i = 0 ; i <= 3 ; i++ )
        initsparse ( &s[i] ) ;

    create_array ( &s[0] ) ;

    create_tuple ( &s[1], s[0] ) ;
    display_tuple ( s[1] ) ;

    create_array ( &s[2] ) ;

    create_tuple ( &s[3], s[2] ) ;
    display_tuple ( s[3] ) ;

    prodmat ( &s[4], s[1], s[3] ) ;

    printf ( "\nResult of multiplication of two matrices: " ) ;
    display_result ( s[4] ) ;

    for ( i = 0 ; i <= 3 ; i++ )
        delsparse ( &s[i] ) ;

    getch( ) ;
}

/* initialises elements of structure */
void initsparse ( struct sparse *p ) { p -> sp = NULL ; p -> result = NULL ; } /* dynamically creates the matrix */
void create_array ( struct sparse *p ) { int n, i ; /* allocate memory */
p -> sp = ( int * ) malloc ( MAX1 * MAX2 * sizeof ( int ) ) ; /* add elements to the array */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ ) { printf ( "Enter element no. %d: ", i ) ; scanf ( "%d", &n ) ; * ( p -> sp + i ) = n ; } } /* displays the contents of the matrix */
void display ( struct sparse s ) { int i ; /* traverses the entire matrix */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ ) { /* positions the cursor to the new line for every new row */
if ( i % 3 == 0 ) printf ( "\n" ) ; printf ( "%d\t", * ( s.sp + i ) ) ; } } /* counts the number of non-zero elements */
int count ( struct sparse s ) { int cnt = 0, i ; for ( i = 0 ; i < MAX1 * MAX2 ; i++ ) { if ( * ( s.sp + i ) != 0 ) cnt++ ; } return cnt ; } /* creates an array that stores information about non-zero elements */
void create_tuple ( struct sparse *p, struct sparse s ) { int r = 0 , c = -1, l = -1, i ; /* get the total number of non-zero elements */
p -> row = count ( s ) + 1 ; /* allocate memory */
p -> sp = ( int * ) malloc ( p -> row * 3 * sizeof ( int ) ) ; /* store information about
total no. of rows, cols, and non-zero values */
* ( p -> sp + 0 ) = MAX1 ; * ( p -> sp + 1 ) = MAX2 ; * ( p -> sp + 2 ) = p -> row - 1 ; l = 2 ; /* scan the array and store info. about non-zero values
in the 3-tuple */
for ( i = 0 ; i < MAX1 * MAX2 ; i++ ) { c++ ; /* sets the row and column values */
if ( ( ( i % 3 ) == 0 ) && ( i != 0 ) ) { r++ ; c = 0 ; } /* checks for non-zero element,
row, column and non-zero value
is assigned to the matrix */
if ( * ( s.sp + i ) != 0 ) { l++ ; * ( p -> sp + l ) = r ; l++ ; * ( p -> sp + l ) = c ; l++ ; * ( p -> sp + l ) = * ( s.sp + i ) ; } } } /* displays the contents of the matrix */
void display_tuple ( struct sparse s ) { int i, j ; /* traverses the entire matrix */
printf ( "\nElements in a 3-tuple: " ) ; j = ( * ( s.sp + 2 ) * 3 ) + 3 ; for ( i = 0 ; i < j ; i++ ) { /* positions the cursor to the new line for every new row */
if ( i % 3 == 0 ) printf ( "\n" ) ; printf ( "%d\t", * ( s.sp + i ) ) ; } printf ( "\n" ) ; } /* performs multiplication of sparse matrices */
void prodmat ( struct sparse *p, struct sparse a, struct sparse b ) { int sum, k, position, posi, flaga, flagb, i , j ; k = 1 ; p -> result = ( int * ) malloc ( MAXSIZE * 3 * sizeof ( int ) ) ; for ( i = 0 ; i < * ( a.sp + 0 * 3 + 0 ) ; i++ ) { for ( j = 0 ; j < * ( b.sp + 0 * 3 + 1 ) ; j++ ) { /* search if an element present at ith row */
searchina ( a.sp, i, &position, &flaga ) ; if ( flaga == TRUE ) { sum = 0 ; /* run loop till there are element at ith row
in first 3-tuple */
while ( * ( a.sp + position * 3 + 0 ) == i ) { /* search if an element present at ith col.
in second 3-tuple */
searchinb ( b.sp, j, * ( a.sp + position * 3 + 1 ), &posi, &flagb ) ; /* if found then multiply */
if ( flagb == TRUE ) sum = sum + * ( a.sp + position * 3 + 2 ) * * ( b.sp + posi * 3 + 2 ) ; position = position + 1 ; } /* add result */
if ( sum != 0 ) { * ( p -> result + k * 3 + 0 ) = i ; * ( p -> result + k * 3 + 1 ) = j ; * ( p -> result + k * 3 + 2 ) = sum ; k = k + 1 ; } } } } /* add total no. of rows, cols and non-zero values */
* ( p -> result + 0 * 3 + 0 ) = * ( a.sp + 0 * 3 + 0 ) ; * ( p -> result + 0 * 3 + 1 ) = * ( b.sp + 0 * 3 + 1 ) ; * ( p -> result + 0 * 3 + 2 ) = k - 1 ; } /* searches if an element present at iith row */
void searchina ( int *sp, int ii, int *p, int *flag ) { int j ; *flag = FALSE ; for ( j = 1 ; j <= * ( sp + 0 * 3 + 2 ) ; j++ ) { if ( * ( sp + j * 3 + 0 ) == ii ) { *p = j ; *flag = TRUE ; return ; } } } /* searches if an element where col. of first 3-tuple
is equal to row of second 3-tuple */
void searchinb ( int *sp, int jj, int colofa, int *p, int *flag ) { int j ; *flag = FALSE ; for ( j = 1 ; j <= * ( sp + 0 * 3 + 2 ) ; j++ ) { if ( * ( sp + j * 3 + 1 ) == jj && * ( sp + j * 3 + 0 ) == colofa ) { *p = j ; *flag = TRUE ; return ; } } } /* displays the contents of the matrix */
void display_result ( struct sparse s ) { int i ; /* traverses the entire matrix */
for ( i = 0 ; i < ( * ( s.result + 0 + 2 ) + 1 ) * 3 ; i++ ) { /* positions the cursor to the new line for every new row */
if ( i % 3 == 0 ) printf ( "\n" ) ; printf ( "%d\t", * ( s.result + i ) ) ; } } /* deallocates memory */
void delsparse ( struct sparse *s ) { if ( s -> sp != NULL ) free ( s -> sp ) ; if ( s -> result != NULL ) free ( s -> result ) ; }
  
Share: 


Didn't find what you were looking for? Find more on Program to multiply two sparse matrices Or get search suggestion and latest updates.

Elizabeth Hughes
Elizabeth Hughes author of Program to multiply two sparse matrices is from London, United Kingdom.
 
View All Articles

 
Please enter your Comment

  • Comment should be atleast 30 Characters.
  • Please put code inside [Code] your code [/Code].

 
No Comment Found, Be the First to post comment!