Scilab Function

gtild - tilde operation

Calling Sequence

Gt=gtild(G)
Gt=gtild(G,flag)

Parameters

Description

If G is a polynomial matrix (or a polynomial), Gt=gtild(G,'c') returns the polynomial matrix Gt(s)=G(-s)'.

If G is a polynomial matrix (or a polynomial), Gt=gtild(G,'d') returns the polynomial matrix Gt=G(1/z)*z^n where n is the maximum degree of G.

For continuous-time systems represented in state-space by a syslin list, Gt = gtild(G,'c') returns a state-space representation of G(-s)' i.e the ABCD matrices of Gt are A',-C', B', D'. If G is improper ( D= D(s)) the D matrix of Gt is D(-s)'.

For discrete-time systems represented in state-space by a syslin list, Gt = gtild(G,'d') returns a state-space representation of G(-1/z)' i.e the (possibly improper) state-space representation of -z*C*inv(z*A-B)*C + D(1/z) .

For rational matrices, Gt = gtild(G,'c') returns the rational matrix Gt(s)=G(-s) and Gt = gtild(G,'d') returns the rational matrix Gt(z)= G(1/z)'.

The parameter flag is necessary when gtild is called with a polynomial argument.

Examples

See Also