# FunctionSpaceToExponentialExpansion(R, FE, x, cen)¶

exprToXXP(fcn, posCheck?) converts the expression fcn to an exponential expansion. If posCheck? is true, log's of negative numbers are not allowed nor are nth roots of negative numbers with n even. If posCheck? is false, these are allowed.
localAbs(fcn) = abs(fcn) or sqrt(fcn^2) depending on whether or not FE has a function abs. This should be a local function, but the compiler won't allow it.