polish error msg for SymEngine

QuantumBFS · Mar 20, 2020 · 8575718 · 8575718
1 parent 3fea7e3
commit 8575718
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/src/register.jl b/src/register.jl
@@ -19,7 +19,9 @@ function parse_str(s::String)
     return v, k - 1
 end
 
-function ket_m end
+function ket_m(s)
+    error("Please install SymEngine and type using SymEngine explicitly to use symbolic functionality of Yao")
+end
 
 function bra_m(s)
     adjoint(ket_m(s))