text: void MV(int dim1, int dim2, double* A, double* x, double* y) {
    int i1,i2;
    register double tmp1;
    for (i2=0; i2<dim2; i2++ ) {
      tmp1=0.0;
      for (i1=0; i1<dim1; i1++ ) 
        tmp1+=A[dim1*i2+i1]*x[i1];
      y[i2]=tmp1;
    }
  }
  