handle exotic types in balance

Author: baggepinnen

lib/ControlSystemsBase/src/matrix_comps.jl

@@ -542,7 +542,7 @@ Compute a similarity transform `T = S*P` resulting in `B = T\\A*T` such that the
 and column norms of `B` are approximately equivalent. If `perm=false`, the
 transformation will only scale `A` using diagonal `S`, and not permute `A` (i.e., set `P=I`).
 """
-function balance(A, perm::Bool=true)
+function balance(A::AbstractMatrix{<:LinearAlgebra.BlasFloat}, perm::Bool=true)
     n = LinearAlgebra.checksquare(A)
     B = copy(A)
     job = perm ? 'B' : 'S'
@@ -570,6 +570,11 @@ function cswap!(i::Integer, j::Integer, X::StridedMatrix)
     end
 end
 
+function balance(A::AbstractMatrix, perm::Bool=true)
+    Ac = Float64.(A)
+    balance(Ac, perm)
+end
+
 
 
 """

lib/ControlSystemsBase/test/test_matrix_comps.jl

@@ -15,6 +15,11 @@ sysb,T = ControlSystemsBase.balance_statespace(sys)
 @test similarity_transform(sysb, T) ≈ sys
 Ab,Bb,Cb,T = ControlSystemsBase.balance_statespace(A,B,C)
 
+sysbb,Tb = ControlSystemsBase.balance_statespace(big(1.0)*sys)
+@test Tb ≈ T
+@test sysbb ≈ sysb
+
+
 @test Ab*T ≈ T*A
 @test Bb ≈ T*B
 @test Cb*T ≈ C