I want to know if my code is well written based on a set of criteria.

2 次查看（过去 30 天）
Daniel
Daniel 2024-3-17
评论： Daniel 2024-3-18
Ran in:
To estimate DIP_s, it is necessary to approximate the expected DIP concentration within the current time step used in the integration(i.e DIP_interm . If the time step is one day, this concentration (DIP_interm) is the sum of the present DIP and the result of Equation 1 with DIP_fert= 0. The difference between DIP_interm and DIP_O is an estimate of DIP_s.
dDIPdt = DIP_Fert + DIP_resp_phy - DIP_grow_phy - (0.1 * DIP) ...............................................................EQN(1)
DIP_req = DIP_grow_phy-(DIP_resp_phy + DIP_msc);
DIP_fert can then be calculated by applying the following rules:
if DIP_interm < DIP_O
DIP_Fert = DIP_req + (DIP_O - DIP_interm);
elseif 0 <= DIP_s <= DIP_req
DIP_Fert = DIP_req - DIP_s;
elseif DIP_s > DIP_req
DIP_Fert = 0;
end
Finally, Equation 1 is re-evaluated by inserting the value of DIP_fert obtained based on the above rules so as to obtain the rate change of DIP. The sum of DIP_fert calculated at each time step over the entire integration period is a rough estimate of the overall fertilizer N requirements for that period
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
% Define simulation period
startdate = datetime(2023, 01, 01, 'Format', 'uuuu-MM-dd');
finishdate = datetime(2023, 06, 30, 'Format', 'uuuu-MM-dd');
tspans = (1:1:days(finishdate - startdate) + 1);
%Dissolved inorganic phosphorous (DIP)
T_w = 20;
T_min = 18;
T_max = 27;
T_opt = 33;
if T_w < T_opt
Tau = exp(-4.6 * ((T_opt - T_w) / (T_opt - T_min)).^4);
else
Tau = exp(-4.6 * ((T_w - T_opt) / (T_max - T_opt)).^4);
end
V_n = 1;
GPP_lambda = 7.0; % assumed as & in g m^-3 d^-1
GPP = GPP_lambda * Tau * V_n;
DIP_IN = 0.2;
DIP_Fert = 0;
Redfield_ratio_p = 0.025;
DIP_grow_phy = GPP*Redfield_ratio_p;
DIP_resp_phy = 0.5 *DIP_grow_phy;
% Initialize DIP
DIP = zeros(length(tspans), 1); % Initialize DIP vector
% Initialize arrays to store DIP_Fert
DIP_Fert_values = zeros(length(tspans), 1);
for t = 1:length(tspans)-1
dDIPdt = @(t, DIP) calculate_dDIPdt(t, DIP, DIP_Fert, DIP_resp_phy, DIP_grow_phy);
[t_integrated, DIP_integrated] = ode45(@(t, DIP) dDIPdt(t, DIP), tspans(t:t+1), DIP_IN);
DIP(t+1) = DIP_integrated(end);
% Recalculate DIP_Fert based on conditions
DIP_O = 0.1;
DIP_msc = 0.1*DIP(t);
DIP_req = DIP_grow_phy-(DIP_resp_phy + DIP_msc);
DIP_interm = DIP(t) + (DIP_resp_phy + DIP_msc - DIP_grow_phy);
DIP_s =max(0,(DIP_interm - DIP_O));
if DIP_interm < DIP_O
DIP_Fert = DIP_req + (DIP_O - DIP_interm);
elseif all((0 <= DIP_s) & (DIP_s <= DIP_req))
DIP_Fert = DIP_req - DIP_s;
elseif DIP_s > DIP_req
DIP_Fert = 0;
end
% Check if DIP_Fert is negative and set it to zero
if DIP_Fert < 0
DIP_Fert = 0;
end
% Update DIP_Fert array
DIP_Fert_values(t+1) = DIP_Fert;
% Update initial condition for the next iteration
DIP_IN = DIP(t+1);
end
% Output DIP_Fert values at different time steps
disp('DIP_Fert values:');
DIP_Fert values:
disp(DIP_Fert_values);
0 0.1131 0 0 0 0 0 0 0 0 0 0.0163 0.0330 0.0294 0.0072 0 0.0020 0.0200 0.0341 0.0262 0.0030 0 0.0066 0.0242 0.0326 0.0200 0 0 0.0133 0.0303 0.0304 0.0112 0 0 0.0179 0.0344 0.0289 0.0050 0 0.0032 0.0211 0.0337 0.0246 0.0020 0 0.0087 0.0261 0.0319 0.0173 0 0 0.0147 0.0315 0.0299 0.0093 0 0.0008 0.0189 0.0345 0.0278 0.0040 0 0.0047 0.0224 0.0332 0.0226 0.0008 0 0.0111 0.0282 0.0311 0.0141 0 0 0.0164 0.0330 0.0294 0.0071 0 0.0020 0.0201 0.0340 0.0261 0.0030 0 0.0067 0.0243 0.0325 0.0199 0 0 0.0134 0.0303 0.0304 0.0110 0 0 0.0180 0.0345 0.0289 0.0050 0 0.0033 0.0212 0.0336 0.0245 0.0020 0 0.0087 0.0261 0.0319 0.0172 0 0 0.0148 0.0316 0.0299 0.0092 0 0.0008 0.0189 0.0344 0.0277 0.0040 0 0.0047 0.0225 0.0332 0.0225 0.0007 0 0.0112 0.0283 0.0311 0.0140 0 0 0.0165 0.0331 0.0294 0.0070 0 0.0021 0.0201 0.0340 0.0260 0.0029 0 0.0068 0.0244 0.0325 0.0197 0 0 0.0135 0.0304 0.0303 0.0110 0 0 0.0180 0.0345 0.0289 0.0049 0 0.0033 0.0212 0.0336 0.0245 0.0019 0 0.0088 0.0262 0.0319 0.0171 0 0 0.0148 0.0316 0.0299 0.0092
% Plot DIP
plot(DIP);
xlabel('Time');
ylabel('Concentration');
legend('DIP',Location='northwest');
function dDIPdt = calculate_dDIPdt(~, DIP, DIP_Fert, DIP_resp_phy, DIP_grow_phy)
dDIPdt = DIP_Fert + DIP_resp_phy - DIP_grow_phy +- (0.1 * DIP);
end

请先登录，再回答此问题。

回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Numerical Integration and Differential Equations 的更多信息

标签

产品


版本

R2023a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by