Calling 32-bit NAG C DLL functions from Visual Basic

8where the rst two arguments specify the numbers of rows and columns in the matrix. Theroutine would treat the array as representing a 3-by-2 matrix stored in row order:0B@11 2131 1222 321CAwhich isnot the intended matrix A.One solution (which is used in Appendix C) is to store the matrix in a 1-dimensional arraya1, with the element a ij stored in a1((i-1)*tda+j-1), where tda is the trailing dimensionof the matrix (in this case 2).Dim a1(5) As DoubleDim tda As Longtda = 2a1(0) = 11a1(1) = 12a1(2) = 21a1(3) = 22a1(4) = 31a1(5) = 32Call f02wec(3,2,a1(0),tda ... )Another solution is to store the transpose of the matrix A in a 2-dimensional array at, withtda now being the leading dimension of the array at:Dim at(1,2) As DoubleDim tda As Longtda = 2at(0,0) = 11at(0,1) = 21at(0,2) = 31at(1,0) = 12at(1,1) = 22at(1,2) = 32Call f02wec(3,2,at(0,0),tda, ... )The Visual Basic array at can be larger than is needed to store the 2-by-3 matrix A T inorder that the C routine accesses the correct array elements it is essential that tda is set tothe correct value: