Dear R-helper,
I have subject 1, 2, 3 and formulation S, MF, MM. I
have a problem in calculating AUC. The AUC (0~t) in
formulation MF and MM were miscalculated, but I don?t
know where my problem is. Here is my code and output.
test<-function( InVVTestindex,
separateWindows=TRUE)
{
for( i in 1:length(unique
(InVVTestindex$subject))){
x<-InVVTestindex$time[InVVTestindex$subject==i]
y<-InVVTestindex$concentration[InVVTestindex$subject==i]
v<-InVVTestindex$formulation[InVVTestindex$subject==i]
w<-InVVTestindex$pH[InVVTestindex$subject==i]
#calculate AUC
add<-function(time,concentration){
auc<-0
for(i in 2:length(time)) {
auc[i]<-1/2*(time[i]-time[i-1])*(concentration[i]+concentration[i-1])
auc[i]<-auc[i]+auc[i-1]
}
return(list(auc=auc))
}
add<-add(x,y)
AUC<-add$auc
#Output
cat("<< Output >>\n")
output<-data.frame(w,i,v,x,y,AUC)
colnames(output)<-list("pH","subject","formulation","time","concentration","AUC(0~t)")
show(output)
cat("\n\n")
}
}
<< Output >>
pH subject formulation time concentration
AUC(0~t)
1 6.8 1 S 0.0 0.00
0.0000
2 6.8 1 S 0.5 110.26
27.5650
3 6.8 1 S 1.0 116.17
84.1725
4 6.8 1 S 1.5 130.20
145.7650
5 6.8 1 S 2.0 145.77
214.7575
6 6.8 1 S 3.0 123.75
349.5175
7 6.8 1 S 4.0 123.05
472.9175
8 6.8 1 S 5.0 82.35
575.6175
9 6.8 1 S 6.0 48.62
641.1025
10 6.8 1 S 8.0 26.51
716.2325
11 6.8 1 S 10.0 3.04
745.7825
12 6.8 1 S 12.0 2.87
751.6925
13 6.8 1 S 24.0 2.74
785.3525
14 6.8 1 MF 0.0 0.00 752.4725
15 6.8 1 MF 0.5 91.67
775.3900
16 6.8 1 MF 1.0 216.78
852.5025
17 6.8 1 MF 1.5 179.91
951.6750
18 6.8 1 MF 2.0 187.02
1043.4075
19 6.8 1 MF 3.0 176.15
1224.9925
20 6.8 1 MF 4.0 171.24
1398.6875
21 6.8 1 MF 5.0 157.83
1563.2225
22 6.8 1 MF 6.0 149.15
1716.7125
23 6.8 1 MF 8.0 142.18
2008.0425
24 6.8 1 MF 10.0 107.56
2257.7825
25 6.8 1 MF 12.0 86.37
2451.7125
26 6.8 1 MF 24.0 9.30
3025.7325
27 6.8 1 MM 0.0 0.00
2914.1325
28 6.8 1 MM 0.5 114.18
2942.6775
29 6.8 1 MM 1.0 160.72
3011.4025
30 6.8 1 MM 1.5 152.28
3089.6525
31 6.8 1 MM 2.0 125.05
3158.9850
32 6.8 1 MM 3.0 118.97
3280.9950
33 6.8 1 MM 4.0 123.26
3402.1100
34 6.8 1 MM 5.0 143.46
3535.4700
35 6.8 1 MM 6.0 137.00
3675.7000
36 6.8 1 MM 8.0 91.48
3904.1800
37 6.8 1 MM 10.0 52.46
4048.1200
38 6.8 1 MM 12.0 15.39
4115.9700
39 6.8 1 MM 24.0 8.00
4256.3100
Best regards,
Hsin-Ya Lee