Solving ODE and using conditions

Hi, after resolving my ODE of n variables I want to write a code to verifiy for exemple if this condition is correct :

n(1)(t=0)+2*n(2)(t=0)+....=n(1)(t)+2*n(2)(t) at each time and execute the code in another file , here is my code:

clear all,clc
 %constantes :::
%temperature
T=17000;
%constante k: recombinaison radiative
k1=2.36 *(1e-12)*(T/300)^(-0.29)*exp(17.60/T); 
k2 =3.24 *(1e-12) *(T/300)^(-0.66);
k3=3.50 *(1e-12)*(T/300)^(-0.53)* exp(3.20/T);
%constante k::Reconmbinaison 
k4=1*10^(-10); 
k5=4.54*10^(-10);
k6=9.10*10^(-10);
k7=8.98*10^(-9)*(T/300)^(-0.5);
k8=5.56*10^(-11)*(T/300)^(0.41)*exp(26.90/T);
k9=4.98*10^(-10)*exp(-18116/T);
k10=6*10^(-11)*(T/300)^(-0.16);
k11=8.69*10^(-11)*exp(-22600/T);
k12=1*10^(-10);
k13=2.94*10^(-11)*(T/300)^(0.5)*exp(-58025/T);
k14=1*10^(-9);
k15=4.80*10^(-10)
k16=1.00*10^(-9)*(T/300)^(-0.5);
k17=8.30*10^(-10);
k18=2.42*10^(-12)*(T/300)^(-0.21)*exp(44/T);
k19=1.18*10^(-11)*exp(-20413/T);
k20=9.82*10^(-12)*(T/300)^(-0.21)*exp(-5.20/T);
k21=1.66*10^(-10)*exp(-14100/T);
k22=1.15*10^(-10)*exp(-13400/T);
k23=2.51*10^(-10)*exp(-38602/T);
k24=1.00*10^(-10);
k25=5.37*10^(-11)*exp(-13800/T);
k26=5.00*10^(-11)*exp(-200/T);
k27=5.00*10^(-12)*exp(-900/T);
k28=6.00*10^(-12);
k29=2.00*10^(-10)*(T/300)^(-0.12);
k30=1.30*10^(-10);
k31=5.00*10^(-10);
k32=2.90*10^(-10);
k33=3.10*10^(-10);
k34=3.66*10^(-11);
k35=2.26*10^(-12)*(T/300)^(0.86)*exp(-3134.0/T);
k36=1.80*10^(-10);
k37=3.38*10^(-11)*(T/300)^(-0.17)*exp(2.80/T);
k38=3*10^(-12);
k39=1.00*10^(-10)*(T/300)^(0.4);
k40=6.10*10^(-10);
k41=1*10^(-13);
k42=5*10^(-11);
k43=5*10^(-11);
k44=1.15*10^(-10);
k45=4*10^(-11);
k46=1*10^(-10);
k47=1.50*10^(-11)*exp(-4300/T);
k48=5.3137*10^(-10);
k49=4.10*10^(-10);
k50=8*10^(-10);
k51=1.32*10^(-12);
k52=2.8*10^(-12)*exp(23400/T);
k53=1*10^(-10)*exp(-55200/T);
k54=8.60*10^(-11);
k55=5.99*10^(-12)*exp(-24075/T);
k56=2.02*10^(-11)*(T/300)^(-0.19)*exp(31.90/T);
k57=2.51*10^(-11)*exp(-30653/T);
k58=3.47*10^(-11)*(T/300)^(-1.33)*exp(-242/T);

%constante k::Recombinaison dissociative
k59=3*10^(-7)*(T/300)^(-0.5);
k60=1.70*10^(-7)*(T/300)^(-0.3);
 
%constante k::Association radiative
k61=4.01*10^(-18)*(T/300)^(0.17)*exp(-101.50/T);
k62=1.08*10^(-18)*(T/300)^(0.07)*exp(-57.50/T);
k63=3.14*10^(-18)*(T/300)^(-0.15)*exp(-68/T);
k64=4.00*10^(-14)*(T/300)^(-1);
k65=4.69*10^(-19)*(T/300)^(1.52)*exp(50.50/T);
k66=3*10^(-16)*(T/300)^(-1);
k67=5*10^(-10)*(T/300)^(-3.7)*exp(-800/T);
k68=4.36*10^(-18)*(T/300)^(0.35)*exp(-161.30/T);
k69=5.72*10^(-19)*(T/300)^(0.37)*exp(-51/T);
k70=4.90*10^(-20)*(T/300)^(1.58);
k71=3.71*10^(-18)*(T/300)^(0.24)*exp(-26.10/T);

%constante k::Transfert de charge
k72=7.05*10^(-10)*(T/300)^(-0.03)*exp(16.70/T);
k73=1*10^(-10);
k74=1.10*10^(-10);
k75=1.10*10^(-10);
k76=1.10*10^(-10);
k77=5.20*10^(-11);
k78=4.80*10^(-10);
k79=4.90*10^(-12)*(T/300)^(0.5)*exp(-4580/T);
k80=6.30*10^(-10);
k81=1.90*10^(-11);
k82=1.00*10^(-11);
k83=1.40*10^(-10);
k84=7.30*10^(-10)*exp(-890/T);
k85=1.00*10^(-9);
k86=3.11*10^(-10);
k87=1.00*10^(-9);
k88=8.25*10^(-10);
k89=1.10*10^(-9)*(T/300)^(-0.50);
k90=4.51*10^(-10);
k91=1* 10^(-11);
k92=8.40*10^(-10);
k93=8.50^(-10);
k94=3.40*10^(-10);
k95=5*10^(-11);
k96=1.20*10^(-10);
k97=6.60*10^(-10);
k98=4.60*10^(-10);
k99=1.00*10^(-10)*(T/300)^(-0.5);
k100=7.40*10^(-11);
k101=6.30*10^(-10);
k102=3.30*10^(-10);
k103=5.70*10^(-10);

%constante k::Neutralisation
k104=7.51*10^(-8)*(T/300)^(-0.5);
k105=7.51*10^(-8)*(T/300)^(-0.5);
k106=7.51*10^(-8)*(T/300)^(-0.5);
k107=7.51*10^(-8)*(T/300)^(-0.5);
k108=7.51*10^(-8)*(T/300)^(-0.5);
k109=7.51*10^(-8)*(T/300)^(-0.5);
k110=7.51*10^(-8)*(T/300)^(-0.50);
k111=7.51*10^(-8)*(T/300)^(-0.50);
k112=7.51*10^(-8)*(T/300)^(-0.50);
k113=7.51*10^(-8)*(T/300)^(-0.50);
k114=7.51*10^(-8)*(T/300)^(-0.5);
k115=7.51*10^(-8)*(T/300)^(-0.5);
k116=7.51*10^(-8)*(T/300)^(-0.5);
k117=7.51*10^(-8)*(T/300)^(-0.5);
%constante k::Photoionisation
k118=3.10*10^(-10)*exp(-3.3/T);
k119=4.90*10^(-8)*exp(-0.50/T);
k120=1.09*10^(-8)*exp(-0.5/T);
k121=4.10*10^(-10)*exp(-3.80/T);
k122=1*10^(-11)*exp(-1.70/T);
k123=2.96*10^(-9)*exp(-2/T);
k124=5*10^(-9)*exp(-2.1/T);
k125=6.88*10^(-9)*exp(-1.5/T);
k126=7.90*10^(-10)*exp(-2.1/T);
k127=6.10*10^(-9)*exp(-0.5/T);
k128=3.50*10^(-11)*exp(-2/T);
k129=2.30*10^(-10)*exp(-3.90/T);
k130=2.10*10^(-10)*exp(-3.50/T);
k131=4.70*10^(-10)*exp(-2.10/T);
%constante k::Attachement radiatif

k132=2.25*10^(-15);
k133=1.50*10^(-15);
k134=2.00*10^(-15)*(T/300)^(-0.5);
k135=1.70*10^(-14)*(T/300)^(-0.5);
%constante k::Détachement associatif

k136=5*10^(-10);
k137=1*10^(-9);
k138=1*10^(-9);
k139=5*10^(-10);
k140=5*10^(-10);
k141=5*10^(-11);
k142=5*10^(-10);
k143=1.90*10^(-10);
k144=2.90*10^(-10);
k145=3.10*10^(-10)*(T/300)^(-0.83);
k146=6.50*10^(-10);
k147=2.20*10^(-10);
k148=1.00*10^(-9);
k149=1*10^(-9);

%constante k::Excitation/ Désexcitation
k150=2.0425*10^(-7)*T^(-0.3)*exp(-29489.55/T);
k151=2.6*10^(-10)*T^(0.89)*exp(-11372.9/T);
k152=1.2*10^(-10)*T^(0.59)*exp(-18916.15/T);
k153=6.0278*10^(-7)*T^(-0.4)*exp(-19880.36/T);
k154=1.6306*10^(-17);
k155=3.6532*10^(-11);

%constante k::Détachement électronique
k156=7*10^(-10);
k157=2*10^(-10);
k158=3.6*10^(-10);

%constante k::Dissociation par impact électronique
k159= 6.2*10^(-10) * T^(1.75) * exp(-113032.7/T );

%constante k::Ionisation par impact électronique
k160= 7.1*10^(-9) * T^(0.76) * exp(-181038/T );

%constante k::Attachement électronique cn(1)6/s
k161=1*10^(-31);
k162=1*10^(-31);

%constante k::Processus de recombinaison cn(1)6/s
k163=5.70*10^(-34)*T^(-2.6);
k164=2.5919*10^(-80);
k165=1.31*10^(-31)*T^(-1.5);
%condition intial 
%IC=IC1=IC2=....=IC43=10^6cm^3
IC =10^18*ones(1,43);
%opt=odeset('OutputFcn',@odeplot,'OutputSel',[1:43]);
tic,[t,n] = ode45(@(t,n)myequations(t,n,k1,k2,k3,k4,k5,k6,k7,k8,k9,k10,k11,k12,k13,k14,k15,k16,k17,k18,k19,k20,k21,k22,k23,k24,k25,k26,k27,k28,k29,k30,k31,k32,k33,k34,k35,k36,k37,k38,k39,k40,k41,k42,k43,k44,k45,k46,k47,k48,k49,k50,k51,k52,k53,k54,k55,k56,k57,k58,k59,k60,k61,k62,k63,k64,k65,k66,k67,k68,k69,k70,k71,k72,k73,k74,k75,k76,k77,k78,k79,k80,k81,k82,k83,k84,k85,k86,k87,k88,k89,k90,k91,k92,k93,k94,k95,k96,k97,k98,k99,k100,k101,k102,k103,k104,k105,k106,k107,k108,k109,k110,k111,k112,k113,k114,k115,k116,k117,k118,k119,k120,k121,k122,k123,k124,k125,k126,k127,k128,k129,k130,k131,k132,k133,k134,k135,k136,k137,k138,k139,k140,k141,k142,k143,k144,k145,k146,k147,k148,k149,k150,k151,k152,k153,k154,k155,k156,k157,k158,k159,k160,k161,k162,k163,k164,k165),[0 10e-3],IC)
toc
function dndt=myequations(t,n,k1,k2,k3,k4,k5,k6,k7,k8,k9,k10,k11,k12,k13,k14,k15,k16,k17,k18,k19,k20,k21,k22,k23,k24,k25,k26,k27,k28,k29,k30,k31,k32,k33,k34,k35,k36,k37,k38,k39,k40,k41,k42,k43,k44,k45,k46,k47,k48,k49,k50,k51,k52,k53,k54,k55,k56,k57,k58,k59,k60,k61,k62,k63,k64,k65,k66,k67,k68,k69,k70,k71,k72,k73,k74,k75,k76,k77,k78,k79,k80,k81,k82,k83,k84,k85,k86,k87,k88,k89,k90,k91,k92,k93,k94,k95,k96,k97,k98,k99,k100,k101,k102,k103,k104,k105,k106,k107,k108,k109,k110,k111,k112,k113,k114,k115,k116,k117,k118,k119,k120,k121,k122,k123,k124,k125,k126,k127,k128,k129,k130,k131,k132,k133,k134,k135,k136,k137,k138,k139,k140,k141,k142,k143,k144,k145,k146,k147,k148,k149,k150,k151,k152,k153,k154,k155,k156,k157,k158,k159,k160,k161,k162,k163,k164,k165)
dndt=zeros(43,1)
%Chemin C
dndt(1)= k1*n(2)*n(42)+k15*n(5)*n(9)+k16*n(5)*n(26)+k25*n(4)*n(26)...
+k29*n(4)*n(9)+k33*n(4)*n(11)+k39*n(7)*n(26)+k40*n(7)*n(27)...
+k43*n(7)*n(9)+k44*n(7)*n(12)+k48*n(9)*n(9)+k59*n(11)*n(42)...
+k72*n(2)*n(24)+k104*n(3)*n(5)+k105*n(3)*n(8)+k106*n(3)*n(25)...
+k117*n(18)*n(2)+k119*n(3)*n(43)+k122*n(11)*n(43)+k124*n(13)*n(43)...
+k130*n(22)*n(43)-k4*n(1)*n(37)-k8*n(1)*n(15)-k9*n(1)*n(26)...
-k10*n(1)*n(24)-k11*n(1)*n(20)-k12*n(1)*n(35)-k13*n(1)*n(22)...
-k61*n(2)*n(1)-k64*n(1)*n(13)-k65*n(1)*n(4)-k66*n(1)*n(9)...
-k67*n(1)*n(5)-k68*n(1)*n(1)-k69*n(1)*n(7)-k73*n(1)*n(27)...
-k74*n(1)*n(11)-k75*n(1)*n(23)-k76*n(1)*n(21)-k77*n(1)*n(19)...
-k118*n(1)*n(43)-k132*n(1)*n(42)-k136*n(1)*n(3)-k137*n(1)*n(12)...
-k138*n(1)*n(14)-k139*n(1)*n(6)-2*k164*n(7)*n(1)*n(1)...
+k164*n(7)*n(1)^(2)-k163*n(1)*n(15)*n(4)+k163*n(1)*n(15)*n(4)...
-k165*n(1)*n(32)*n(4)+k165*n(1)*n(32)*n(4);
%Chemin C+:
dndt(2)= -k1*n(2)*n(42)-k5*n(2)*n(15)-k6*n(2)*n(30)-k7*n(2)*n(36)...
-k61*n(2)*n(1)-k62*n(2)*n(7)-k63*n(2)*n(4)-k72*n(2)*n(24)...
-k117*n(18)*n(2)+k45*n(7)*n(11)+k73*n(1)*n(27)...
+k74*n(1)*n(11)+k75*n(1)*n(23)+k76*n(1)*n(21)...
+k77*n(1)*n(19)+k118*n(1)*n(43)+k122*n(11)*n(43);
%Chemin C-:
dndt(3)= k32*n(4)*n(12)+k132*n(1)*n(42)-k14*n(3)*n(24)-k104*n(3)*n(5)...
-k105*n(3)*n(8)-k106*n(3)*n(25)-k119*n(3)*n(43)...
-k136*n(1)*n(3)-k140*n(3)*n(4)-k141*n(3)*n(15)-k142*n(3)*n(7);
%Chemin O:
dndt(4)= k2*n(5)*n(42)+k8*n(1)*n(15)+k10*n(1)*n(24)+k13*n(1)*n(22)...
+k14*n(3)*n(24)+k35*n(7)*n(15)+k36*n(7)*n(19)...
+k37*n(7)*n(24)+k38*n(7)*n(32)+k52*n(15)*n(24)...
+k53*n(15)*n(20)+k55*n(15)*n(22)+k56*n(15)*n(26)...
+k78*n(5)*n(9)+k79*n(5)*n(22)+k80*n(5)*n(30)...
+k81*n(5)*n(15)+k84*n(6)*n(15)+k85*n(6)*n(26)...
+k104*n(3)*n(5)+2*k107*n(5)*n(6)+k108*n(5)*n(18)...
+k109*n(6)*n(8)+k120*n(6)*n(43)+2*k126*n(15)*n(43)...
+k128*n(19)*n(43)+k130*n(22)*n(43)+k131*n(24)*n(43)...
+k162*n(42)*n(4)*n(15)-k19*n(4)*n(24)-k20*n(4)*n(32)...
-k21*n(4)*n(30)-k22*n(4)*n(30)-k23*n(4)*n(20)...
-k24*n(4)*n(36)-k25*n(4)*n(26)-k26*n(4)*n(26)...
-k27*n(4)*n(13)-k28*n(4)*n(35)-k29*n(4)*n(9)...
-k30*n(4)*n(21)-k31*n(4)*n(14)-k32*n(4)*n(12)...
-k33*n(4)*n(11)-k63*n(2)*n(4)-k65*n(1)*n(4)...
-2*k70*n(4)*n(4)-k82*n(4)*n(21)-k83*n(4)*n(23)...
-k133*n(4)*n(42)-k140*n(3)*n(4)-k143*n(4)*n(6)...
-k144*n(4)*n(12)-k161*n(42)*n(4)*n(15)...
-k162*n(42)*n(4)*n(15)-k163*n(1)*n(15)*n(4)-k165*n(1)*n(32)*n(4);
%Chemin O+:
dndt(5)= k5*n(2)*n(15)+k34*n(8)*n(15)+k82*n(4)*n(21)...
+k83*n(4)*n(23)+k128*n(19)*n(43)-k19*n(4)*n(24)...
-k20*n(4)*n(32)-k21*n(4)*n(30)-k22*n(4)*n(30)...
-k23*n(4)*n(20)-k24*n(4)*n(36)-k25*n(4)*n(26)...
-k26*n(4)*n(26)-k27*n(4)*n(13)-k28*n(4)*n(35)...
-k29*n(4)*n(9)-k30*n(4)*n(21)-k31*n(4)*n(14)...
-k32*n(4)*n(12)-k33*n(4)*n(11)-k63*n(2)*n(4)...
-k65*n(1)*n(4)-2*k70*n(4)*n(4)-k82*n(4)*n(21)...
-k83*n(4)*n(23)-k133*n(4)*n(42)-k140*n(3)*n(4)...
-k143*n(4)*n(6)-k144*n(4)*n(12)-k161*n(42)*n(4)*n(15)...
-k162*n(42)*n(4)*n(15)-k163*n(1)*n(15)*n(4)-k165*n(1)*n(32)*n(4);
%Chemin O-:
dndt(6)= k133*n(4)*n(42)+k161*n(42)*n(4)*n(15)-k84*n(6)*n(15)...
-k85*n(6)*n(26)-k107*n(5)*n(6)-k109*n(6)*n(8)-k120*n(6)*n(43)...
-k139*n(1)*n(6)-k143*n(4)*n(6)-k145*n(6)*n(24)...
-k146*n(6)*n(22)-k147*n(6)*n(7);
%Chemin N:
dndt(7)= k3*n(8)*n(42)+k9*n(1)*n(26)+k11*n(1)*n(20)...
+k18*n(5)*n(20)+k19*n(4)*n(24)+k23*n(4)*n(20)...
+k26*n(4)*n(26)+k30*n(4)*n(21)+2*k60*n(21)*n(42)...
+k86*n(8)*n(15)+k87*n(8)*n(9)+k88*n(8)*n(22)...
+k89*n(8)*n(26)+k90*n(8)*n(24)+k105*n(3)*n(8)...
+k109*n(6)*n(8)+k110*n(8)*n(18)+k111*n(8)*n(12)...
+k112*n(8)*n(28)+k113*n(8)*n(14)+2*k129*n(20)*n(43)...
+k131*n(24)*n(43)+2*k159*n(20)*n(42)-k35*n(7)*n(15)...
-k36*n(7)*n(19)-k37*n(7)*n(24)-k38*n(7)*n(32)...
-k39*n(7)*n(26)-k40*n(7)*n(27)-k41*n(7)*n(13)...
-k42*n(7)*n(14)-k43*n(7)*n(9)-k44*n(7)*n(12)...
-k45*n(7)*n(11)-k46*n(7)*n(35)-k62*n(2)*n(7)...
-k69*n(1)*n(7)-k71*n(8)*n(7)-k91*n(7)*n(21)...
-k142*n(3)*n(7)-k147*n(6)*n(7)-k164*n(7)*n(1)*n(1);
%Chemin N+:
dndt(8)=k91*n(7)*n(21)-k3*n(8)*n(42)-k34*n(8)*n(15)...
-k71*n(8)*n(7)-k86*n(8)*n(15)-k87*n(8)*n(9)...
-k88*n(8)*n(22)-k89*n(8)*n(26)-k90*n(8)*n(24)...
-k105*n(3)*n(8)-k109*n(6)*n(8)-k110*n(8)*n(18)...
-k111*n(8)*n(12)-k112*n(8)*n(28)-k113*n(8)*n(14);
%Chemin C2:
dndt(9)= k9*n(1)*n(26)+k12*n(1)*n(35)+k13*n(1)*n(22)...
+k27*n(4)*n(13)+k41*n(7)*n(13)+k68*n(1)*n(1)...
+k74*n(1)*n(11)+k94*n(11)*n(24)+k111*n(8)*n(12)...
+k115*n(12)*n(25)+k121*n(9)*n(43)+k123*n(12)*n(43)...
+k124*n(13)*n(43)+k136*n(1)*n(3)+k153*n(10)*n(42)...
+k154*n(10)^(2)+k155*n(10)*n(1)-k15*n(5)*n(9)...
-k29*n(4)*n(9)-k43*n(7)*n(9)-k47*n(9)*n(15)...
-2*k48*n(9)*n(9)-k49*n(9)*n(19)-k66*n(1)*n(9)...
-k78*n(5)*n(9)-k87*n(8)*n(9)-k92*n(9)*n(23)...
-k93*n(9)*n(27)-k121*n(9)*n(43)-k134*n(9)*n(42)...
-k148*n(9)*n(12)-k150*n(9)*n(42);
%Chemin C2(d)
dndt(10)= k150*n(9)*n(42)-k153*n(10)*n(42)-k154*n(10)^(2)-k155*n(10)*n(1);
%Chemin C2+:
dndt(11)= k61*n(2)*n(1)+k78*n(5)*n(9)+k87*n(8)*n(9)...
+k92*n(9)*n(23)+k93*n(9)*n(27)-k33*n(4)*n(11)...
-k45*n(7)*n(11)-k50*n(11)*n(15)-k59*n(11)*n(42)...
-k74*n(1)*n(11)-k94*n(11)*n(24)-k122*n(11)*n(43);
%Chemin C2-:
dndt(12)= -k32*n(4)*n(12)-k44*n(7)*n(12)-k111*n(8)*n(12)...
-k115*n(12)*n(25)-k123*n(12)*n(43)-k137*n(1)*n(12)...
-k144*n(4)*n(12)-k148*n(9)*n(12)-k149*n(12)*n(13)...
+k31*n(4)*n(14)+k42*n(7)*n(14)+k134*n(9)*n(42);
%Chemin C3:
dndt(13)= k48*n(9)*n(9)+k66*n(1)*n(9)+k113*n(8)*n(14)...
+k114*n(14)*n(25)+k125*n(14)*n(43)...
+k137*n(1)*n(12)-k27*n(4)*n(13)-k41*n(7)*n(13)...
-k64*n(1)*n(13)-k124*n(13)*n(43)...
-k135*n(13)*n(42)-k149*n(12)*n(13);
%Chemin C3-:
dndt(14)= k135*n(13)*n(42)-k31*n(4)*n(14)...
-k42*n(7)*n(14)-k113*n(8)*n(14)...
-k114*n(14)*n(25)-k125*n(14)*n(43)-k138*n(1)*n(14);
%Chemin O2:
dndt(15)= k17*n(5)*n(32)+k19*n(4)*n(24)+k20*n(4)*n(32)...
+k21*n(4)*n(30)+k57*n(24)*n(24)+k70*n(4)*n(4)...
+k77*n(1)*n(19)+k97*n(19)*n(32)+k98*n(19)*n(24)...
+k108*n(5)*n(18)+k110*n(8)*n(18)+k116*n(18)*n(25)...
+k117*n(18)*n(2)+k127*n(18)*n(43)+k143*n(4)*n(6)...
+2*k156*n(18)*n(15)+2*k157*n(18)*n(16)...
+2*k158*n(18)*n(17)+k161*n(42)*n(4)*n(15)...
-k5*n(2)*n(15)-k8*n(1)*n(15)-k34*n(8)*n(15)...
-k35*n(7)*n(15)-k47*n(9)*n(15)-k50*n(11)*n(15)...
-k51*n(15)*n(37)-k52*n(15)*n(24)-k53*n(15)*n(20)...
-k54*n(15)*n(27)-k55*n(15)*n(22)-k56*n(15)*n(26)...
-k81*n(5)*n(15)-k84*n(6)*n(15)-k86*n(8)*n(15)...
-k95*n(15)*n(21)-k96*n(15)*n(23)-k126*n(15)*n(43)...
-k141*n(3)*n(15)-k151*n(15)*n(42)-k152*n(15)*n(42)...
-k156*n(18)*n(15)-k161*n(42)*n(4)*n(15)...
-k162*n(42)*n(4)*n(15)-k163*n(1)*n(15)*n(4);
%Chemin O2(a):
dndt(16)= k151*n(42)*n(15)-k157*n(16)*n(18);
%Chemin O2(b):
dndt(17)= k152*n(42)*n(15)-k158*n(17)*n(18);
%Chemin O2-:
dndt(18)= k84*n(6)*n(15)+k162*n(42)*n(4)*n(15)...
-k108*n(5)*n(18)-k110*n(8)*n(18)...
-k116*n(18)*n(25)-k117*n(18)*n(2)-k127*n(18)*n(43)...
-k156*n(18)*n(15)-k157*n(18)*n(16)-k158*n(18)*n(17);
%Chemin O2+:
dndt(19)= k81*n(5)*n(15)+k86*n(8)*n(15)+k95*n(15)*n(21)...
+k96*n(15)*n(23)-k36*n(7)*n(19)-k49*n(9)*n(19)-k77*n(1)*n(19)...
-k97*n(19)*n(32)-k98*n(19)*n(24)-k128*n(19)*n(43);
%Chemin N2:
dndt(20)= k21*n(4)*n(30)+k37*n(7)*n(24)+k39*n(7)*n(26)...
+k57*n(24)*n(24)+k76*n(1)*n(21)+k82*n(4)*n(21)...
+k91*n(7)*n(21)+k95*n(15)*n(21)+k99*n(21)*n(26)...
+k100*n(21)*n(22)-k11*n(1)*n(20)-k18*n(5)*n(20)...
-k23*n(4)*n(20)-k53*n(15)*n(20)...
-k129*n(20)*n(43)-k159*n(20)*n(42)-k160*n(20)*n(42);
%Chemin N2+:
dndt(21)= k40*n(7)*n(27)+k71*n(8)*n(7)+k160*n(20)*n(42)...
-k30*n(4)*n(21)-k60*n(21)*n(42)-k76*n(1)*n(21)...
-k82*n(4)*n(21)-k91*n(7)*n(21)...
-k95*n(15)*n(21)-k99*n(21)*n(26)-k100*n(21)*n(22);
%Chemin CO:
dndt(22)= k4*n(1)*n(37)+k5*n(2)*n(15)+k8*n(1)*n(15)...
+k24*n(4)*n(36)+k26*n(4)*n(26)+k27*n(4)*n(13)...
+k28*n(4)*n(35)+k29*n(4)*n(9)+k31*n(4)*n(14)...
+k32*n(4)*n(12)+2*k47*n(9)*n(15)+k49*n(9)*n(19)...
+k50*n(11)*n(15)+k54*n(15)*n(27)+k58*n(24)*n(37)...
+k65*n(1)*n(4)+k75*n(1)*n(23)+k83*n(4)*n(23)...
+k92*n(9)*n(23)+k96*n(15)*n(23)+k102*n(24)*n(23)...
+k139*n(1)*n(6)+k140*n(3)*n(4)-k13*n(1)*n(22)...
-k55*n(15)*n(22)-k79*n(5)*n(22)-k88*n(8)*n(22)...
-k100*n(21)*n(22)-k101*n(22)*n(27)...
-k130*n(22)*n(43)-k146*n(6)*n(22);
%Chemin CO+:
dndt(23)= k7*n(2)*n(36)+k15*n(5)*n(9)+k33*n(4)*n(11)...
+k49*n(9)*n(19)+k50*n(11)*n(15)+k63*n(2)*n(4)...
+k67*n(1)*n(5)+k79*n(5)*n(22)+k88*n(8)*n(22)...
+k100*n(21)*n(22)+k101*n(22)*n(27)-k75*n(1)*n(23)...
-k83*n(4)*n(23)-k92*n(9)*n(23)...
-k96*n(15)*n(23)-k102*n(24)*n(23);
%Chemin NO:
dndt(24)= k20*n(4)*n(32)+k22*2*n(4)*n(30)+k23*n(4)*n(20)...
+k24*n(4)*n(36)+k25*n(4)*n(26)+k34*n(8)*n(15)...
+k35*n(7)*n(15)+k51*n(15)*n(37)+k106*n(3)*n(25)...
+k114*n(14)*n(25)+k115*n(12)*n(25)+k116*n(18)*n(25)...
+k147*n(6)*n(7)-k10*n(1)*n(24)-k14*n(3)*n(24)-k19*n(4)*n(24)...
-k37*n(7)*n(24)-k52*n(15)*n(24)-k57*2*n(24)*n(24)...
-k58*n(24)*n(37)-k72*n(2)*n(24)-k90*n(8)*n(24)...
-k94*n(11)*n(24)-k98*n(19)*n(24)-k102*n(24)*n(23)...
-k103*n(24)*n(27)-k131*n(24)*n(43)-k145*n(6)*n(24);
%Chemin NO+:
dndt(25)= k6*n(2)*n(30)+k16*n(5)*n(26)+k17*n(5)*n(32)...
+k18*n(5)*n(20)+k30*n(4)*n(21)+k36*n(7)*n(19)...
+k54*n(15)*n(27)+k72*n(2)*n(24)+k90*n(8)*n(24)...
+k94*n(11)*n(24)+k98*n(19)*n(24)+k102*n(24)*n(23)...
+k103*n(24)*n(27)-k106*n(3)*n(25)-k114*n(14)*n(25)...
-k115*n(12)*n(25)-k116*n(18)*n(25);
%Chemin CN:
dndt(26)= k4*n(1)*n(37)+k6*n(2)*n(30)+k7*n(2)*n(36)...
+k10*n(1)*n(24)+k11*n(1)*n(20)+k12*n(1)*n(35)...
+k28*n(4)*n(35)+k41*n(7)*n(13)+k42*n(7)*n(14)...
+k43*n(7)*n(9)+k45*n(7)*n(11)+k46*2*n(7)*n(35)...
+k69*n(1)*n(7)+k73*n(1)*n(27)+k93*n(9)*n(27)...
+k101*n(22)*n(27)+k103*n(24)*n(27)...
+k112*n(8)*n(28)+k142*n(3)*n(7)...
+k164*n(7)*n(1)*n(1)-k9*n(1)*n(26)-k16*n(5)*n(26)...
-k25*n(4)*n(26)-k26*n(4)*n(26)-k39*n(7)*n(26)...
-k56*n(15)*n(26)-k85*n(6)*n(26)...
-k89*n(8)*n(26)-k99*n(21)*n(26);
%Chemin CN+:
dndt(27)= k62*n(2)*n(7)+k89*n(8)*n(26)+k99*n(21)*n(26)...
-k40*n(7)*n(27)-k54*n(15)*n(27)...
-k73*n(1)*n(27)-k93*n(9)*n(27)...
-k101*n(22)*n(27)-k103*n(24)*n(27);
%Chemin CN-:
dndt(28)= k14*n(3)*n(24)+k44*n(7)*n(12)+k85*n(6)*n(26)-k112*n(8)*n(28);
%Chemin O3:
dndt(29)= k163*n(1)*n(15)*n(4);
%Chemin N2O:
dndt(30)= k38*n(7)*n(32)+k53*n(15)*n(20)+k58*n(24)*n(37)...
-k6*n(2)*n(30)-k21*n(4)*n(30)...
-k22*n(4)*n(30)-k80*n(5)*n(30);
%Chemin N2O+:
dndt(31)= k80*n(5)*n(30);
%Chemin NO2:
dndt(32)= k52*n(15)*n(24)+k145*n(6)*n(24)-k17*n(5)*n(32)...
-k20*n(4)*n(32)-k38*n(7)*n(32)...
-k97*n(19)*n(32)-k165*n(1)*n(32)*n(4);
%Chemin NO2+:
dndt(33)= k97*n(19)*n(32);
%Chemin CO2:
dndt(34)= k51*n(15)*n(37)+k55*n(15)*n(22)...
+k141*n(3)*n(15)+k146*n(6)*n(22);
%Chemin C2N:
dndt(35)= -k12*n(1)*n(35)-k28*n(4)*n(35)-k46*n(7)*n(35);
%Chemin CNO:
dndt(36)= -k7*n(2)*n(36)-k24*n(4)*n(36);
%Chemin OCN
dndt(37)= -k4*n(1)*n(37)-k51*n(15)*n(37)...
-k58*n(24)*n(37)+k56*n(15)*n(26);
%Chemin NO3:
dndt(38)= k165*n(1)*n(32)*n(4);
%Chemin C2O:
dndt(39)= k144*n(4)*n(12);
%Chemin C4:
dndt(40)= k64*n(1)*n(13)+k138*n(1)*n(14)+k148*n(9)*n(12);
%Chemin C5:
dndt(41)= k149*n(12)*n(13);
%Chemin e:
dndt(42)= k118*n(1)*n(43)+k119*n(3)*n(43)+k120*n(6)*n(43)...
+k121*n(12)*n(43)+k123*n(12)*n(43)+k125*n(14)*n(43)...
+k127*n(18)*n(43)+k136*n(1)*n(3)+k137*n(1)*n(12)...
+k138*n(1)*n(14)+k139*n(1)*n(6)+k140*n(3)*n(4)...
+k141*n(3)*n(15)+k142*n(3)*n(7)+k143*n(4)*n(6)...
+k144*n(4)*n(12)+k145*n(6)*n(24)+k146*n(6)*n(22)...
+k147*n(6)*n(7)+k148*n(9)*n(12)+k149*n(12)*n(13)...
+k150*n(9)*n(42)+k151*n(15)*n(42)+k152*n(15)*n(42)...
+k153*n(10)*n(42)+k156*n(18)*n(15)+k157*n(18)*n(16)...
+k158*n(18)*n(17)+k159*n(20)*n(42)...
+2*k160*n(20)*n(42)-k1*n(2)*n(42)-k2*n(5)*n(42)...
-k3*n(8)*n(42)-k59*n(11)*n(42)-k60*n(21)*n(42)...
-k132*n(1)*n(42)-k133*n(4)*n(42)-k134*n(9)*n(42)...
-k135*n(13)*n(42)-k150*n(9)*n(42)-k151*n(15)*n(42)...
-k152*n(15)*n(42)-k153*n(10)*n(42)-k159*n(20)*n(42)...
-k160*n(20)*n(42)-k161*n(42)*n(4)*n(15)...
-k162*n(42)*n(4)*n(15);
%Chemin hv:
dndt(43)= -k118*n(1)*n(43)-k119*n(3)*n(43)-k120*n(6)*n(43)...
-k121*n(9)*n(43)-k122*n(11)*n(43)-k123*n(12)*n(43)...
-k124*n(13)*n(43)-k125*n(14)*n(43)-k126*n(15)*n(43)...
-k127*n(18)*n(43)-k128*n(19)*n(43)-k129*n(20)*n(43)...
-k130*n(22)*n(43)-k131*n(24)*n(43)+k1*n(2)*n(42)...
+k2*n(5)*n(42)+k3*n(8)*n(42)+k61*n(2)*n(1)...
+k62*n(2)*n(7)+k63*n(2)*n(4)+k64*n(1)*n(13)...
+k65*n(1)*n(4)+k66*n(1)*n(9)+k67*n(1)*n(5)...
+k68*n(1)*n(1)+k69*n(1)*n(7)+k70*n(4)*n(4)...
+k71*n(8)*n(7)+k132*n(1)*n(42)+k133*n(4)*n(42)...
+k134*n(9)*n(42)+k135*n(13)*n(42);
end 

Answer 1

[Torsten]

After the call to ode45, insert (without semicolon at the end of the line)

expr_at_0 = n(1,1)+2*n(1,2)

expr_at_end = n(end,1)+2*n(end,2)

n1(t=0)+2*n2(t=0) and in the next line n1(t=tend)+2*n2(t=tend) will be printed

[Imene Yed]

thnak you so much for the anwser sir but can you please explain to me this methode .

[Torsten]

After the call to ode45, the solution at all output times is stored in the matrix n.

It is a (ntimes x 43) matrix. n(i,j) is the solution for n(j) at output time t(i).

The vector t is a (ntimes x1) vector containing the output times.

Now you can combine the vectors according to your needs.

[Imene Yed]

@Torstenthanks sir but I would like to verify the equation at each t .

[Torsten]

expr_at_i(:)= n(:,1) + 2*n(:,2);

Now store t and expr_at_i to a file:

save expr.txt t expr_at_i -ascii

[Imene Yed]

Error using save

Unable to write file expr.txt: permission denied.

Error in finalODE (line 207)

save expr.txt t expr_at_i -ascii

[Torsten]

Here I can't help.

It seems you don't have writing permission in the directory you are working in.

After starting matlab, change to a directory where you have permission to write using the "cd" command. Or - if you have the right to do that - change the previleges in the directory you are working in.

[Imene Yed]

Thank you for all your help,but I would like to write this code in another script(because you see I have a long script) but it doesn't seem to work ,

[Imene Yed]

thank you so much for your help sir

[Torsten]

Call a function (maybe named "function postprocess") with t and n as inputs and postprocess the solution there according to your needs.

[Imene Yed]

@Torsten is there any other way to put the algorithm that you proposed to me in another script and call my previous code ?

[Torsten]

Make a script "postprocess.m" like

function [] = postprocess(t,n)

% postprocess your solution here according to your needs

end

Call this script after the call to ode45 as

postprocess(t,n);

[Imene Yed]

thank you so much sir !!!!you're the best

[Imene Yed]

sir I did as you said but It doesnt seem to display the values of my prostprocess script.i ddidnt find them in the workspace ,I found only n.

[Torsten]

But I thought you wanted to write them to file in "postprocess".

Why do you search for them in the workspace ?

[Imene Yed]

I made another script

Make a script "postprocess.m"

function [] = postprocess(t,n)

% postprocess your solution here according to your needs

end

Call this script after the call to ode45 as

postprocess(t,n);

I executed the old file (the one with ODE45)

[Imene Yed]

I'm looking for the rsults on the postprocesus file Ididnt find it

[Torsten]

I don't know what you mean.

What do you want to do in "postprocess" ? I assumed you save results and maybe some deduced variables in "postprocess". But you will have to program it in this function.

[Imene Yed]

I mean I want to use this script(postprocess) to do my calculus :

expr_at_0 = n(1,1)+2*n(1,2)

.......

by importing the n and t values from the previuous script(where there is ODE45) because my old script is already big .