diff --git a/HCS_Toolbox_ver01/c_hpc.m b/HCS_Toolbox_ver01/c_hpc.m
index 31cac113c702af46472665206c03da483bf18ae2..b12a53f5b2e03232b381e0b16b24c6116fe4deff 100644
--- a/HCS_Toolbox_ver01/c_hpc.m
+++ b/HCS_Toolbox_ver01/c_hpc.m
@@ -34,7 +34,7 @@ hn=hnorm(x,Gd,P);
 if hn^(-mu)>-mu*rho*h*n-tol
 F0=A+B*(K0+K)+rho*Gd;
 s=log(1+mu*rho*h*n*hn^mu)/(rho*mu);
-Q=expm(rho*Gd*log(hn))*expm(-rho*Gd*s)*expm(F0*s)*expm(-rho*Gd*log(hn));
+Q=expm(Gd*log(hn))*expm(-rho*Gd*s)*expm(F0*s)*expm(-Gd*log(hn));
 else Q=zeros(size(A));
 end;