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70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
/*
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C code of two 2 by 2 matrix multiplication using Strassen's algorithm
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*/
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#include<stdio.h>
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int main()
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{
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int a[2][2], b[2][2], c[2][2], i, j;
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int m1, m2, m3, m4, m5, m6, m7;
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printf("Enter the 4 elements of first matrix: ");
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for(i = 0; i < 2; i++)
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for(j = 0; j < 2; j++)
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scanf("%d", &a[i][j]);
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printf("Enter the 4 elements of second matrix: ");
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for(i = 0; i < 2; i++)
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for(j = 0; j < 2; j++)
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scanf("%d", &b[i][j]);
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printf("\nThe first matrix is\n");
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for(i = 0; i < 2; i++)
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{
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printf("\n");
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for(j = 0; j < 2; j++)
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printf("%d\t", a[i][j]);
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}
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printf("\nThe second matrix is\n");
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for(i = 0; i < 2; i++)
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{
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printf("\n");
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for(j = 0; j < 2; j++)
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printf("%d\t", b[i][j]);
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}
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m1= (a[0][0] + a[1][1]) * (b[0][0] + b[1][1]);
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m2= (a[1][0] + a[1][1]) * b[0][0];
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m3= a[0][0] * (b[0][1] - b[1][1]);
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m4= a[1][1] * (b[1][0] - b[0][0]);
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m5= (a[0][0] + a[0][1]) * b[1][1];
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m6= (a[1][0] - a[0][0]) * (b[0][0]+b[0][1]);
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m7= (a[0][1] - a[1][1]) * (b[1][0]+b[1][1]);
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c[0][0] = m1 + m4- m5 + m7;
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c[0][1] = m3 + m5;
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c[1][0] = m2 + m4;
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c[1][1] = m1 - m2 + m3 + m6;
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printf("\nAfter multiplication using Strassen's algorithm \n");
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for(i = 0; i < 2 ; i++)
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{
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printf("\n");
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for(j = 0; j < 2; j++)
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printf("%d\t", c[i][j]);
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}
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return 0;
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}
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/*
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Enter the 4 elements of first matrix:
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1 2
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3 4
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Enter the 4 elements of second matrix:
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5 6
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7 8
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The first matrix is
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1 2
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3 4
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The second matrix is
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5 6
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7 8
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After multiplication using Strassen's algorithm
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19 22
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43 50
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