Unsure of what is happening in for loop
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Dear all,
I have the following for loop,
T92to20_state_d = [2.50926000000000; 5.04629166666667; 3.81944833333333];
Rn92to20_state_d = [24.1978271186779; 24.8685463692206; 24.5147611929163];
LvETPM92to20_state_d = [11.5146886953329; 10.5486657087851; 10.7259878112342];
GE92to20_state_d = [-12.3855735457507; -12.1467974925575; -12.2727450153218];
windspd92to20_state_d_2 = [1.64395657249513; 1.16191506903469; 1.62723837006298];
T4 = [276.391481481482; 277.285000000000; 277.706296296296];
Pressure_atmos = [99.189335562566010];
k = 0.35;
z1 = 0.5; z2 = 1.14;
z0 = 0.21756875;
T = T92to20_state_d + 273.16;
H_old = Rn92to20_state_d - LvETPM92to20_state_d - GE92to20_state_d;
H92to20_state_d = H_old;
delta1 = ones(size(H_old));
L = ones(size(1:length(Rn92to20_state_d)+1));
zeta_old = zeros(size(H_old));
l = 0;
for i = 1:3
while delta1(i) > 0.01
u_s(i) = (k.*windspd92to20_state_d_2(i)*0.277778*z1)/(log(z1/z0) - 4.7*zeta_old(i));
L(i) = (T(i)*u_s(i)^3*1010*1.225)/(k*9.81*H92to20_state_d(i));
a(i) = 122.44*Pressure_atmos/T(i);
b(i) = u_s(i)*abs(T4(i) - T(i));
c(i) = 0.74*log(z2/z1) + (4.7/L(i))*(z2-z1);
H(i) = a(i)*b(i)/c(i);
zeta(i) = z2/L(i);
delta1(i) = (L(i+1)-L(i))./L(i);
H92to20_state_d(i) = H(i);
zeta_old(i) = zeta(i);
l = l+1;
end
end
Using manual calculation, I can get the values for i = 1 but not for i = 2 and 3.
% u_s(2) = (k.*windspd92to20_state_d_2(2)*0.277778*z1)/(log(z1/z0) - 4.7*zeta_old(2))
% = 0.2444 (but answer from loop is 0.0679).
% delta1(1) = -0.6625 (but answer from loop is -0.7151)
I can't seem to find the problem. Thank you in advance.
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Mathieu NOE
le 8 Déc 2021
hello
I don't get why the while loop is for ?
The for loop by itself will generate this result
delta1 =
-0.7151
-0.1559
-0.6961
so the condition while delta1(i) > 0.01 is never met
I a have a feeling the code implementation is maybe not what is should be but I don't understand what is the target here
I beleive the code does even not need that for loop as it should be vectorized
also why have created the variable "l" which is incremented ?
so code sligthly modified for my test purpose
clc
clearvars
T92to20_state_d = [2.50926000000000; 5.04629166666667; 3.81944833333333];
Rn92to20_state_d = [24.1978271186779; 24.8685463692206; 24.5147611929163];
LvETPM92to20_state_d = [11.5146886953329; 10.5486657087851; 10.7259878112342];
GE92to20_state_d = [-12.3855735457507; -12.1467974925575; -12.2727450153218];
windspd92to20_state_d_2 = [1.64395657249513; 1.16191506903469; 1.62723837006298];
T4 = [276.391481481482; 277.285000000000; 277.706296296296];
Pressure_atmos = [99.189335562566010];
k = 0.35;
z1 = 0.5; z2 = 1.14;
z0 = 0.21756875;
T = T92to20_state_d + 273.16;
H_old = Rn92to20_state_d - LvETPM92to20_state_d - GE92to20_state_d;
H92to20_state_d = H_old;
delta1 = ones(size(H_old));
L = ones(size(1:length(Rn92to20_state_d)+1));
zeta_old = zeros(size(H_old));
l = 0;
% for i = 1:3
% while delta1(ci) > 0.01
for ci = 1:3
u_s(ci) = (k.*windspd92to20_state_d_2(ci)*0.277778*z1)/(log(z1/z0) - 4.7*zeta_old(ci));
L(ci) = (T(ci)*u_s(ci)^3*1010*1.225)/(k*9.81*H92to20_state_d(ci));
a(ci) = 122.44*Pressure_atmos/T(ci);
b(ci) = u_s(ci)*abs(T4(ci) - T(ci));
c(ci) = 0.74*log(z2/z1) + (4.7/L(ci))*(z2-z1);
H(ci) = a(ci)*b(ci)/c(ci);
zeta(ci) = z2/L(ci);
delta1(ci) = (L(ci+1)-L(ci))./L(ci);
H92to20_state_d(ci) = H(ci);
zeta_old(ci) = zeta(ci);
l = l+1; % what is the purpose of this ?
end
% end
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