Matric and C

Posted 2020-06-26

Definition

https://www.mathsisfun.com/algebra/matrix-introduction.html

How to do Multiplication

a(m,n)*b(n,p)->c(m,p)

https://www.mathsisfun.com/algebra/matrix-multiplying.html

Online calculator

http://matrix.reshish.com/multCalculation.php

C implementation 

/* Multiplying matrix a and b and storing in array mult. */
    for(i=0; i<r1; ++i)
    for(j=0; j<c2; ++j)
    for(k=0; k<c1; ++k)
    {
        mult[i][j]+=a[i][k]*b[k][j];
    }

/*mat(r*c) *mat(r),v will have k rows,1 column

for(i=0;i<k;i++)

for(j=0;j<k;j++)
   v[i]+=mat[i][j]*v2[j];

*/

/*v1 has k columns and 1 row,v has 1 coumn,k rows,result will have one

row,one column,so only using a variable to store is ok

for(i=0;i<k;i++)
      result=result+v1[i]*v[i];

*/