Undefined function or variable 'solv'.

I am using ode45 to solve 32 coupled ODEs. I am not used to matlab, so it could be a very simple fix, but when attempting to solve the system, I get the error "Undefined function or variable 'solv' ," where 'solv' is my function.

function diff = solv(t,x)
Vex = x(1);
Vatt_hi= x(2);
Vatt_lo= x(3);
Ven= x(4);

Vp_cyt= x(5);
Vp_nuc= x(6);

Rc= x(7);
Rv= x(8);

Rc_rdrp= x(9);
Rv_rdrp= x(10);

Cp= x(11);

Vpnuc_m1= x(12);
Vpcyt_m1= x(13);

Rm_1= x(14);
Rm_2= x(15);
Rm_3= x(16);
Rm_4= x(17);
Rm_5= x(18);
Rm_6= x(19);
Rm_7= x(20);
Rm_8= x(21);

Ppb1= x(22);
Ppb2= x(23);
Ppa= x(24);
Prdrp= x(25);
Pnp= x(26);
Pm1= x(27);
Pnep= x(28);
Pha= x(29);
Pna= x(30);
Pm2= x(31);

vrel = x(32);


diff(1,1) = kdis_hi * Vatt_hi + kdis_lo * Vatt_lo - (katt_hi * (btot_hi - Vatt_hi) + katt_lo * (btot_lo - Vatt_lo)) * Vex;
diff(2,1) = katt_hi * (btot_hi - Vatt_hi) * Vex - (kdis_hi + ken) * Vatt_hi;
diff(3,1) = katt_lo * (btot_lo - Vatt_lo) * Vex - (kdis_lo + ken) * Vatt_lo;
diff(4,1) = ken * (Vatt_hi + Vatt_lo) - (kfus + kdeg_Ven) * Ven;
diff(5,1) = 8 * kfus * Ven - kimp * Vp_cyt;
diff(6,1) = kimp * Vp_cyt + kbind_np * Pnp * Rv_rdrp - (kbind_m1 * Pm1 + kdeg_rnp) * Vp_nuc;
diff(7,1) = ksyn_c * Vp_nuc - kbind_rdrp * Prdrp * Rc - kdeg_r * Rc;
diff(8,1) = ksyn_v * Cp - kbind_rdrp * Prdrp * Rv - kdeg_r * Rv;
diff(9,1) = kbind_rdrp * Prdrp * Rc - kbind_np * Pnp * Rc_rdrp - kdeg_rrdrp * Rc_rdrp;
diff(10,1) = kbind_rdrp * Prdrp * Rv - kbind_np * Pnp * Rv_rdrp - kdeg_rrdrp * Rv_rdrp;
diff(11,1) = kbind_np * Pnp * Rc_rdrp - kdeg_rnp * Cp;
diff(12,1) = kbind_m1 * Pm1 * Vp_nuc - (kexp * Pnep + kdeg_rnp) * Vpnuc_m1;
diff(13,1) = kexp * Pnep * Vpnuc_m1 - 8 * vrel - kdeg_rnp * Vpcyt_m1;
diff(14,1) = (ksyn_m / l1) * (Vp_nuc / 8) - kdeg_m * Rm_1;
diff(15,1) = (ksyn_m / l2) * (Vp_nuc / 8) - kdeg_m * Rm_2;
diff(16,1) = (ksyn_m / l3) * (Vp_nuc / 8) - kdeg_m * Rm_3;
diff(17,1) = (ksyn_m / l4) * (Vp_nuc / 8) - kdeg_m * Rm_4;
diff(18,1) = (ksyn_m / l5) * (Vp_nuc / 8) - kdeg_m * Rm_5;
diff(19,1) = (ksyn_m / l6) * (Vp_nuc / 8) - kdeg_m * Rm_6;
diff(20,1) = (ksyn_m / l7) * (Vp_nuc / 8) - kdeg_m * Rm_7;
diff(21,1) = (ksyn_m / l8) * (Vp_nuc / 8) - kdeg_m * Rm_8;
diff(22,1) = (ksyn_p / drib) * Rm_2 - krdrp * Ppb1 * Ppb2 * Ppa;
diff(23,1) = (ksyn_p / drib) * Rm_1 - krdrp * Ppb1 * Ppb2 * Ppa;
diff(24,1) = (ksyn_p / drib) * Rm_3 - krdrp * Ppb1 * Ppb2 * Ppa;
diff(25,1) = krdrp * Ppb1 * Ppb2 * Ppa - kbind_rdrp * Prdrp * (Rv + x(7)) - (n_prdrp - 8) * vrel;
diff(26,1) = (ksyn_p / drib) * Rm_5 - (lv / nnuc_np) * kbind_np * Pnp * (Rc_rdrp + Rv_rdrp) - (n_pnp - 8 * (lv / nnuc_np)) * vrel;
diff(27,1) = (ksyn_p / drib)*(1 - f_spl7) * Rm_7 - (lv / nnuc_m1) * kbind_m1 * x(6) - (n_pm1 - 8 * (lv / nnuc_m1)) * vrel;
diff(28,1) = (ksyn_p / drib) * f_spl8 * Rm_8 - (lv / nnuc_nep) * kexp * Pnep * Vpnuc_m1 - (n_pnep - 8 * (lv / nnuc_nep)) * vrel;
diff(29,1) = (ksyn_p / drib) * Rm_4 - n_pha * vrel;
diff(30,1) = (ksyn_p / drib) * Rm_6 - n_pna * vrel;
diff(31,1) = (ksyn_p / drib) * f_spl7 * Rm_7 - n_pm2 * vrel;
diff(32,1) = krel * Vpcyt_m1 * ((Prdrp/(Prdrp + kv_rel * n_prdrp)) * (Pha/(Pha + kv_rel * n_pha)) * (Pnp/(Pnp + kv_rel * n_pnp)) * (Pna/(Pna + kv_rel * n_pna)) * (Pm1/(Pm1 + kv_rel * n_pm1)) * (Pm2/(Pm2 + kv_rel * n_pm1)) * (Pnep/(Pnep + kv_rel * n_pnep)));

end

% in another file
t = linspace(0,60);
x = [10 100 0 0 0 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0];

[time,xsol] = ode45(@solv,t,x);

Answer 1

[Star Strider]

Where did you save it?

You must save it to a directory or your MATLAB user path, and MATLAB has to know that directory exists.

See: What Is the MATLAB Search Path? and Add Folders to the MATLAB Search Path at Startup

[Bill Bastian]

Both files are saved to the same directory which has been added to the user path.

[Steven Lord]

Is your solv function in a file named solv.m or is the file under a different name? The recommendation is that the main function in a file share its name with the file. If they do differ, MATLAB will know the function by the file name.

% if this is in a file timesthree.m you will need to call it like:
%
% y = timesthree(5) % y is 10
function y = timestwo(x)
y = 2*x;
end

[Bill Bastian]

That was the problem, thank you!