Hi my friends

I have COMSOL Multiphysics 5.1 and when I compute study of "gaas_pin_photodiode.mph" It has errors..

Why?

- Function: ^

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.gdm1.D@VDN$t

- Defined as: (((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5)))

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.gdm1.Nd0@VDN$t

- Defined as: (comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2)))

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.gdm1.Na@VDN$t

- Defined as: comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2))))

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.Na@VDN$t

- Defined as: comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2))))

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.Naminus@VDN$t

- Defined as: comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2))))

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.Ndoping@VDN$t

- Defined as: ((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2)))))

Failed to evaluate temporary symbolic derivative variable.

- Variable: comp1.semi.n_eq@VDN$t

- Defined as: (((((((((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2))))))*0.5)*(2*(0.5*comp1.semi.Ndoping)))+((2*comp1.semi.ni_mod)*(comp1.semi.ni_eff*((((comp1.semi.gamma_n*comp1.semi.gamma_p)^(-0.5))*0.5)*((comp1.semi.gamma_p*(((1/(1e-300+exp(comp1.semi.eta_n)))*(exp(comp1.semi.log_FD_half(comp1.semi.eta_n))*(dcomp1.semi.log_FD_half_dx1(comp1.semi.eta_n)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_n)*((1/(1e-300+(abs(comp1.Ne)/comp1.semi.Nc)))*((1/comp1.semi.Nc)*real(conj(sign(comp1.Ne))*comp1.Net)))))))+(((-comp1.semi.FD_half_etaeff_n)/((1e-300+exp(comp1.semi.eta_n))^2))*(exp(comp1.semi.eta_n)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_n)*((1/(1e-300+(abs(comp1.Ne)/comp1.semi.Nc)))*((1/comp1.semi.Nc)*real(conj(sign(comp1.Ne))*comp1.Net))))))))+(comp1.semi.gamma_n*(((1/(1e-300+exp(comp1.semi.eta_p)))*(exp(comp1.semi.log_FD_half(comp1.semi.eta_p))*(dcomp1.semi.log_FD_half_dx1(comp1.semi.eta_p)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_p)*((1/(1e-300+(abs(comp1.Ph)/comp1.semi.Nv)))*((1/comp1.semi.Nv)*real(conj(sign(comp1.Ph))*comp1.Pht)))))))+(((-comp1.semi.FD_half_etaeff_p)/((1e-300+exp(comp1.semi.eta_p))^2))*(exp(comp1.semi.eta_p)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_p)*((1/(1e-300+(abs(comp1.Ph)/comp1.semi.Nv)))*((1/comp1.semi.Nv)*real(conj(sign(comp1.Ph))*comp1.Pht)))))))))))))*(0.5*((((0.5*comp1.semi.Ndoping)^2)+(comp1.semi.ni_mod^2))^(-0.5))))+(real(conj(sign(comp1.semi.Ndoping))*(((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2)))))))*0.5))*(comp1.semi.Ndoping>=0))+((((((((((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2))))))*0.5)*(2*(0.5*comp1.semi.Ndoping)))+((2*comp1.semi.ni_mod)*(comp1.semi.ni_eff*((((comp1.semi.gamma_n*comp1.semi.gamma_p)^(-0.5))*0.5)*((comp1.semi.gamma_p*(((1/(1e-300+exp(comp1.semi.eta_n)))*(exp(comp1.semi.log_FD_half(comp1.semi.eta_n))*(dcomp1.semi.log_FD_half_dx1(comp1.semi.eta_n)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_n)*((1/(1e-300+(abs(comp1.Ne)/comp1.semi.Nc)))*((1/comp1.semi.Nc)*real(conj(sign(comp1.Ne))*comp1.Net)))))))+(((-comp1.semi.FD_half_etaeff_n)/((1e-300+exp(comp1.semi.eta_n))^2))*(exp(comp1.semi.eta_n)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_n)*((1/(1e-300+(abs(comp1.Ne)/comp1.semi.Nc)))*((1/comp1.semi.Nc)*real(conj(sign(comp1.Ne))*comp1.Net))))))))+(comp1.semi.gamma_n*(((1/(1e-300+exp(comp1.semi.eta_p)))*(exp(comp1.semi.log_FD_half(comp1.semi.eta_p))*(dcomp1.semi.log_FD_half_dx1(comp1.semi.eta_p)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_p)*((1/(1e-300+(abs(comp1.Ph)/comp1.semi.Nv)))*((1/comp1.semi.Nv)*real(conj(sign(comp1.Ph))*comp1.Pht)))))))+(((-comp1.semi.FD_half_etaeff_p)/((1e-300+exp(comp1.semi.eta_p))^2))*(exp(comp1.semi.eta_p)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_p)*((1/(1e-300+(abs(comp1.Ph)/comp1.semi.Nv)))*((1/comp1.semi.Nv)*real(conj(sign(comp1.Ph))*comp1.Pht)))))))))))))*(0.5*((((0.5*comp1.semi.Ndoping)^2)+(comp1.semi.ni_mod^2))^(-0.5))))+(real(conj(sign(comp1.semi.Ndoping))*(((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2)))))))*0.5))*((-((comp1.semi.Ndoping=0))+((((((((((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2))))))*0.5)*(2*(0.5*comp1.semi.Ndoping)))+((2*comp1.semi.ni_mod)*(comp1.semi.ni_eff*((((comp1.semi.gamma_n*comp1.semi.gamma_p)^(-0.5))*0.5)*((comp1.semi.gamma_p*(((1/(1e-300+exp(comp1.semi.eta_n)))*(exp(comp1.semi.log_FD_half(comp1.semi.eta_n))*(dcomp1.semi.log_FD_half_dx1(comp1.semi.eta_n)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_n)*((1/(1e-300+(abs(comp1.Ne)/comp1.semi.Nc)))*((1/comp1.semi.Nc)*real(conj(sign(comp1.Ne))*comp1.Net)))))))+(((-comp1.semi.FD_half_etaeff_n)/((1e-300+exp(comp1.semi.eta_n))^2))*(exp(comp1.semi.eta_n)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_n)*((1/(1e-300+(abs(comp1.Ne)/comp1.semi.Nc)))*((1/comp1.semi.Nc)*real(conj(sign(comp1.Ne))*comp1.Net))))))))+(comp1.semi.gamma_n*(((1/(1e-300+exp(comp1.semi.eta_p)))*(exp(comp1.semi.log_FD_half(comp1.semi.eta_p))*(dcomp1.semi.log_FD_half_dx1(comp1.semi.eta_p)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_p)*((1/(1e-300+(abs(comp1.Ph)/comp1.semi.Nv)))*((1/comp1.semi.Nv)*real(conj(sign(comp1.Ph))*comp1.Pht)))))))+(((-comp1.semi.FD_half_etaeff_p)/((1e-300+exp(comp1.semi.eta_p))^2))*(exp(comp1.semi.eta_p)*(dcomp1.semi.log_FD_half_inv_dx1(comp1.semi.logx_p)*((1/(1e-300+(abs(comp1.Ph)/comp1.semi.Nv)))*((1/comp1.semi.Nv)*real(conj(sign(comp1.Ph))*comp1.Pht)))))))))))))*(0.5*((((0.5*comp1.semi.Ndoping)^2)+(comp1.semi.ni_mod^2))^(-0.5))))+(real(conj(sign(comp1.semi.Ndoping))*(((((-((((((-comp1.semi.gdm2.genext1(d(y,t)))*(2*(y-comp1.semi.gdm2.genext1(y))))+((2*(x-comp1.semi.gdm2.genext1(x)))*(-comp1.semi.gdm2.genext1(d(x,t)))))*(0.5*((((y-comp1.semi.gdm2.genext1(y))^2)+((x-comp1.semi.gdm2.genext1(x))^2))^(-0.5))))*(1/comp1.semi.gdm2.ch_geo))*(2*(comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo))))*exp(-((comp1.semi.gdm2.D/comp1.semi.gdm2.ch_geo)^2)))*(comp1.semi.gdm2.cp_dtd*comp1.semi.gdm2.Ngeo))*comp1.semi.gdm2.cp_dtd)-(comp1.semi.gdm1.cp_dtd*((comp1.semi.gdm1.Ngeo*comp1.semi.gdm1.cp_dtd)*((-((((((-comp1.semi.gdm1.genext1(d(x,t)))*((x-comp1.semi.gdm1.genext1(x))*2))+(((y-comp1.semi.gdm1.genext1(y))*2)*(-comp1.semi.gdm1.genext1(d(y,t)))))*(0.5*((((x-comp1.semi.gdm1.genext1(x))^2)+((y-comp1.semi.gdm1.genext1(y))^2))^(-0.5))))*(1/comp1.semi.gdm1.ch_geo))*((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)*2)))*exp(-((comp1.semi.gdm1.D/comp1.semi.gdm1.ch_geo)^2)))))))*0.5))*((-((comp1.semi.Ndoping