# NDSolve::ndfdmc: Computed derivatives do not have dimensionality consistent with the initial conditions. >>

I am trying to solve this NDSolve problem and I am getting the above error and do not know why. Here is what I have:

rh := 0.9;
uh := 0.4;
eh := 1;
rv := 33;
uv := 0.271;
ev := 1;
p1 := 0.05;
p2 := 0.1;

s =
NDSolve[{y'[t] == (rh*y[t] (1 - y[t]/0.14)) - uh* y[t],
x'[t] == (rv*x[t] (1 - x[t]/129)) -
uv*x[t] - (Min[(x[t]/y[t])/10, 1])*y[t], y[0] == 0.080,
x[0] == 128}, {y[t], x[t]}, {t, 0, 20000}, MaxSteps -> 1000000]

Nh[t_] := Evaluate[y[t] /. s];
Nv[t_] := Evaluate[x[t] /. s];
Q[t_] := Evaluate[(x[t]/y[t]) /. s];
bh[Nh[t_]] := Evaluate[rh*Nh[t] (1 - Nh[t]/0.14)];
bv[Nv[t_]] := Evaluate[rv*Nv[t] (1 - Nv[t]/129)];
Qv := 100;
Qh := 10;
x1 := 0.755;
x2 := 0.431;
alpha := 0.862;
y1 := (1 - x1^(1/alpha))^alpha;
y2 := (1 - x2^(1/alpha))^alpha;
betah1 := 0.525*x1*ev;
betah2 := 0.525*x2*ev;
betav := 9.67*ev;
ch1[t_] := betah1*Min[(Q[t]/Qv), 1];
ch2[t_] := betah2*Min[(Q[t]/Qv), 1];
cv[t_] := betav*Min[(Qv/Q[t]), 1];
rh1 := 1*y1;
rh2 := 1*y2;
Eh[t_] := eh*Min[(Q[t]/Qh), 1];

syste = {
Sh'[t] == (1 - ((p1*Ih1[t] - p2*Ih2[t])/Nh[t]))*(bh[
Nh[t]]) - (ch1[t] +
rh1*Eh[t])*(Sh[t]*(Iv1[t]/Nv[t])) - (ch2[t] +
rh2*Eh[t])*(Sh[t]*(Iv2[t]/Nv[t])) - uh*Sh[t],

Ih1'[t] ==
p1*(Ih1[t]/Nh[t])*(bh[Nh[t]]) + (ch1[t] + rh1*Eh[t])*
Sh[t]*(Iv1[t]/Nv[t]) - uh*Ih1[t],

Ih2'[t] ==
p2*(Ih2[t]/Nh[t])*(bh[Nh[t]]) + (ch2[t] + rh2*Eh[t])*
Sh[t]*(Iv2[t]/Nv[t]) - uh*Ih2[t],

Sv'[t] ==
bv[Nv[t]] - cv[t]*Sv[t]*(Ih1[t]/Nh[t]) -
cv[t]*Sv[t]*(Ih2[t]/Nh[t]) - uv*Nv[t] - Eh[t]*Nh[t]*(Sv[t]/Nv[t]),

Iv1'[t] ==
cv[t]*Sv[t]*(Ih1[t]/Nh[t]) - uv*Iv1[t] -
Eh[t]*Nh[t]*(Iv1[t]/Nv[t]),

Iv2'[t] ==
cv[t]*Sv[t]*(Ih2[t]/Nh[t]) - uv*Iv2[t] -
Eh[t]*Nh[t]*(Iv2[t]/Nv[t]), Sh[0] == 0.04904, Ih1[0] == 0.00096,
Ih2[0] == 0.1 .03, Sv[0] == 55.68, Iv1[0] == 0.32, Iv2[0] == 72};

sol =
NDSolve[syste, {Sh, Ih1, Ih2, Sv, Iv1, Iv2}, {t, 0, 500},
MaxSteps -> 500000];


During evaluation of In[40]:= NDSolve::ndfdmc: Computed derivatives do not have dimensionality consistent with the initial conditions. >>

Any suggestions?

-
NDSolve::ndfdmc errors are usually localized to your problem. Please see previous questions on the same error here and see if you've made the same mistakes as any of them. –  rm -rf Apr 4 at 14:17