Description: The sign function did not handle nan correctly. This patch fixes it.
Forwarded: not-needed
Origin: https://gitlab.com/conradsnicta/armadillo-code/-/commit/50c5c2d619a3b529ad83ce517393c37d685acf3d

diff -Naur armadillo-10.1.2/include/armadillo_bits/arma_cmath.hpp armadillo-10.1.2-fix/include/armadillo_bits/arma_cmath.hpp
--- armadillo-10.1.2/include/armadillo_bits/arma_cmath.hpp	2016-06-17 02:22:12.000000000 +1000
+++ armadillo-10.1.2-fix/include/armadillo_bits/arma_cmath.hpp	2016-06-17 02:22:13.000000000 +1000
@@ -183,7 +183,7 @@
 typename arma_real_only<eT>::result
 arma_sign(const eT x)
   {
-  return (x > eT(0)) ? eT(+1) : ( (x < eT(0)) ? eT(-1) : eT(0) );
+  return (x > eT(0)) ? eT(+1) : ( (x < eT(0)) ? eT(-1) : ((x == eT(0)) ? eT(0) : x) );
   }