Not enough input arguments. Error in mypde_model>bcfun (line 53) ptop =utop - interp1(time, mydata(:,5), t,'spline'); Error in mypde_model (line 17) sol = pdepe(m, @pdefun,

Dear expert;

Could you help me figure out why the bcfun function is not working and help fix the problem?

Thank you!

clear
close all
clc
load mydata.mat
time = datetime(mydata.DAY) + (mydata.HOUR + mydata.QHR/4)/24; % matrix (35040 X 1)
Z=17; % depth in inches
z = linspace(0,Z,200); % length vector
t = linspace(0, 100,35040);% time vector
m= 0;
u_ini1= -4.705; %Temperature [deg C] 
u_ini2= -0.594; % Temperature [deg C] 
% solve pdepe-------------------------------------------------
sol = pdepe(m, @pdefun, @icfun, bcfun, z, t);
T = sol(:,:,1);
%Temperature profile at final time t
figure (1)
plot(t, T(end,:))
xlabel('Time')
ylabel('Temperature [deg C]')
% Build function for PDEs -------------------------------
function [c,f,s] = pdefun(z,t, u, dudz)
K =1.2;    % conductivity(W/m-K)
rho=2200;  % density(kg/m^3)                   
Cp=921;     % specific heat capacity(J/kg-K)
c=rho*Cp/K;
f = dudz;
s = 0;
end
% build function for initial conditions------------------------
function u0 = icfun(z, T_ini1,T_ini2, Z)
u_ini1= -4.705; 
u_ini2= -0.594; 
u0 = T_ini1 + z/Z*(T_ini2-T_ini1);
end
% build function for boundary conditions-----------------------
function [ptop,qtop, pbot,qbot] = bcfun(ztop, utop, zbot, ubot,t,time, mydata)
ptop =utop - interp1(time, mydata(:,5), t,'spline'); %?????.......
qtop= 0; 
pbot = -ubot + interp1(time, mydata(:,end), t, 'spline');%????......
qbot= 1;
end 

Answer 1

[Torsten]

Use

sol = pdepe(m, @pdefun, @(z)icfun(z,u_ini1,u_ini2, Z),@(ztop, utop, zbot, ubot,t) bcfun(ztop, utop, zbot, ubot,t,time, mydata), z, t);

instead of

sol = pdepe(m, @pdefun, @icfun, bcfun, z, t);

[Sanley Guerrier]

Thank you, Torsten

I used your code, it did not work.

Error using datetime/interp1

X and XQ must both be datetime arrays, or both be numeric.

Error in mypde_model>bcfun (line 48)

ptop =utop - interp1(time, mydata(:,5), t,'spline'); %?????.......

Error in mypde_model>@(ztop,utop,zbot,ubot,t)bcfun(ztop,utop,zbot,ubot,t,time,mydata) (line 16)

sol = pdepe(m, @pdefun, @(x)icfun(x,u_ini1,u_ini2, Z),@(ztop, utop, zbot, ubot,t) bcfun(ztop, utop, zbot,

ubot,t,time, mydata), z, t);

Error in pdepe (line 251)

[pL,qL,pR,qR] = feval(bc,xmesh(1),y0(:,1),xmesh(nx),y0(:,nx),t(1),varargin{:});

Error in mypde_model (line 16)

sol = pdepe(m, @pdefun, @(x)icfun(x,u_ini1,u_ini2, Z),@(ztop, utop, zbot, ubot,t) bcfun(ztop, utop, zbot,

ubot,t,time, mydata), z, t);

[Torsten]

I don't know what kind of arrays you pass to "bcfun". To make interp1 work, the arrays "time" and "mydata" must both be numeric and the array "time" must be strictly monotonic.

And my guess is that "qbot" should be 0 instead of 1.

[Sanley Guerrier]

Insulated at the bottom, du/dz =0.

I thought qbot would be 1.

[Torsten]

Then pbot=0, qbot=1.

[Sanley Guerrier]

Thank you for helping.

I am going to mess a little bit with the array "time". Right now it is a "datetime" array.

[Torsten]

Maybe

https://uk.mathworks.com/help/matlab/ref/datetime.convertto.html

can help.

Note that your "time" vector should include the time interval "t" you use for the integration.