Really compiles now...

binder/postBuild

 #!/bin/bash
 set -ex
-CXX=clang++ pip install git+git://github.com/ianhbell/teqp.git
\ No newline at end of file
+CXX=clang++ python setup.py install
\ No newline at end of file

include/teqp/types.hpp

@@ -38,6 +38,10 @@ auto forceeval(T&& expr)
 template<typename T> struct is_complex_t : public std::false_type {};
 template<typename T> struct is_complex_t<std::complex<T>> : public std::true_type {};
 
+// See https://stackoverflow.com/a/41438758
+template<typename T> struct is_mcx_t : public std::false_type {};
+template<typename T> struct is_mcx_t<mcx::MultiComplex<T>> : public std::true_type {};
+
 template<typename T>
 auto getbaseval(const T& expr)
 {
@@ -48,6 +52,9 @@ auto getbaseval(const T& expr)
     else if constexpr (is_complex_t<T>()) {
         return expr.real();
     }
+    else if constexpr (is_mcx_t<T>()) {
+        return expr.real();
+    }
     else {
         return expr;
     }

src/multifluid.cpp

-#define USE_AUTODIFF
-
 #include "teqp/core.hpp"
 #include "teqp/models/multifluid.hpp"
 
 #include <optional>
 
-
-
 template<typename J>
 void time_calls(const std::string &coolprop_root, const J &BIPcollection) {
     auto model = build_multifluid_model({ "methane", "ethane" }, coolprop_root, BIPcollection);