How to create a symbolic vandermonde matrix in matlab?

I am trying to create a symbolic vandermonde matrix in matlab, but not able to do! I see the function vander() creates a matrix with numbers. But I want to create a symbolic representation; so that I can further take an inverse of that.

AX = b ; I know A = vandermonder matrix of size (nxn) and I know b is of size (nx1) both A and b are arbitraty and A is vandermonde type matrix.

How to create that A and also such that I can take the inverse as well!

Any help with this! Thanks.

[Matt J]

But I want to create a symbolic representation; so that I can further take an inverse of that.

Why would you wish to do that? Why not just use polyfit(), as is normally done?

Answer 1

[Chunru]

N = 4;
A = sym('A', [N, N])

A = 

v = sym('v', [N, 1]);
A = v.^(N-1:-1:0)

A = 

inv(A)

ans = 

[Anshuman]

Great, thanks a lot! And what about creating a MxN vandermonde matrix ; may you kindly help which lines I should modify? Will it be.

A = sym('A', [M, N])
v = sym('v', [N, 1]);
A = v.^(N-1:-1:0)

[Chunru]

M = 4; N = 5;
A = sym('A', [M, N])

A = 

v = sym('v', [M, 1]);
A = v.^(N-1:-1:0)

A = 

[Anshuman]

Also how to create a vandermonde MxN matrix, with entries from 0-1 equal spaced; I can create it for MxM type matrix but not able to do so in MxN ;

In MxM I have ; what to do in MxN ; where M is between [0-1] equally spaced and N is the degree to which I want to take the vandermonde matrix.

t1 = linspace(0,1,M);
A = fliplr(vander(t1));