I just entered into the space of data mining, machine learning and clustering. I'm having special problem, and do not know which technique to use it for solving it.
I want to perform clustering of observations (objects or whatever) on specific data format. All variables in each observation is numeric. My data input looks like this:
1 2 3 4 5 6
1 3 5 7
2 9 10 11 12 13 14
45 1 22 23 24
Let's say that n represent row (observation, or 1D vector,..) and m represents column (variable index in each vector). n could be very large number, and 0 < m < 100. Also main point is that same observation (row) cannot have identical values (in 1st row, one value could appear only once).
So, I want to somehow perform clustering where I'll put observations in one cluster based on number of identical values which contain each row/observation.
If there are two rows like:
1
1 2 3 4 5
They should be clustered in same cluster, if there are no match than for sure not. Also number of each rows in one cluster should not go above 100.
Sick problem..? If not, just for info that I didn't mention time dimension. But let's skip that for now.
So, any directions from you guys,
Thanks and best regards,
JDK
Its hard to recommend anything since your problem is totally vague, and we have no information on the data. Data mining (and in particular explorative techniques like clustering) is all about understanding the data. So we cannot provide the ultimate answer.
Two things for you to consider:
1. if the data indicates presence of species or traits, Jaccard similarity (and other set based metrics) are worth a try.
2. if absence is less informative, maybe you should be mining association rules, not clusters
Either way, without understanding your data these numbers are as good as random numbers. You can easily cluster random numbers, and spend weeks to get the best useless result!
Can your problem be treated as a Bag-of-words model, where each article (observation row) has no more than 100 terms?
Anyway, I think your have to give more information and examples about "why" and "how" you want to cluster these data. For example, we have:
1 2 3
2 3 4
2 3 4 5
1 2 3 4
3 4 6
6 7 8
9 10
9 11
10 12 13 14
What is your expected clustering? How many clusters are there in this clustering? Only two clusters?
Before you give more information, according to you current description, I think you do not need a cluster algorithm, but a structure of connected components. The first round you process the dataset to get the information of connected components, and you need a second round to check each row belong to which connected components. Take the example above, first round:
1 2 3 : 1 <- 1, 1 <- 2, 1 <- 3 (all point linked to the smallest point to
represent they are belong to the same cluster of the smallest point)
2 3 4 : 2 <- 4 (2 and 3 have already linked to 1 which is <= 2, so they do
not need to change)
2 3 4 5 : 2 <- 5
1 2 3 4 : 1 <- 4 (in fact this change are not essential because we have
1 <- 2 <- 4, but change this can speed up the second round)
3 4 6 : 3 <- 6
6 7 8 : 6 <- 7, 6 <- 8
9 10 : 9 <- 9, 9 <- 10
9 11 : 9 <- 11
10 11 12 13 14 : 10 <- 12, 10 <- 13, 10 <- 14
Now we have a forest structure to represent the connected components of points. The second round you can easily pick up one point in each row (the smallest one is the best) and trace its root in the forest. The rows which have the same root are in the same, in your words, cluster. For example:
1 2 3 : 1 <- 1, cluster root 1
2 3 4 5 : 1 <- 1 <- 2, cluster root 1
6 7 8 : 1 <- 1 <- 3 <- 6, cluster root 1
9 10 : 9 <- 9, cluster root 9
10 11 12 13 14 : 9 <- 9 <- 10, cluster root 9
This process takes O(k) space where k is the number of points, and O(nm + nh) time, where r is the height of the forest structure, where r << m.
I am not sure if this is the result you want.
Related
Table 1:
Position
Team
1
MCI
2
LIV
3
MAN
4
CHE
5
LEI
6
AST
7
BOU
8
BRI
9
NEW
10
TOT
Table 2
Position
Team
1
LIV
2
MAN
3
MCI
4
CHE
5
AST
6
LEI
7
BOU
8
TOT
9
BRI
10
NEW
Output I'm looking for is
Position difference = 10 as that is the total of the positional difference. How can I do this in excel/google sheets? So the positional difference is always a positive even if it goes up or down. Think of it as a league table.
Table 2 New (using formula to find positional difference):
Position
Team
Positional Difference
1
LIV
1
2
MAN
1
3
MCI
2
4
CHE
0
5
AST
1
6
LEI
1
7
BOU
0
8
TOT
2
9
BRI
1
10
NEW
1
Try this:
=IFNA(ABS(INDEX(A:B,MATCH(E2,B:B,0),1)-D2),"-")
Assuming that table 1 is at columns A:B:
As im so new to this field and im trying to explore the data for a time series, and find the missing values and count them and study a distribution of their length and fill in these gaps, the thing is i have, let's say 10 file.txt and for each file i have 2 columns as follows:
C1 C2
944 0
920 1
920 2
928 3
912 7
920 8
920 9
880 10
888 11
920 12
944 13
and so on... lets say till 100 and not necessarily the 10 files have the same number of observations.
so here for example the missing values and not necessarily appears in all files that i have, missing value are: 4,5 and 6 in C2 and the corresponding 1st column C1(measured in milliseconds, so the value of 928ms is not a time neighbor of 912ms). So i want to find those gaps(the total missing values in all 10 files) and show a histogram of their lengths.
i wrote a piece of code in R, but the problem is that i don't get the exact total number that i should have for the missing values.
path = "files path"
out.file<-data.frame(TS = 0, Index = 0, File = '')
file.names <- dir(path, pattern =".txt")
for(i in 1:length(file.names)){
file <- cbind(read.table(file.names[i],
header=F,
sep ="\t",
stringsAsFactors=FALSE),
file.names[i])
colnames(file) <- c('TS', 'Index', 'File')
out.file <- rbind(out.file, file)
}
d = dim(out.file)[1]
misDa = 0
for(i in 2:(d-1)){
if(abs(out.file$Index[i]-out.file$Index[i+1]) > 1)
misDa = misDa+1
}
Hard to give specific hints without having a more extensive example of your data that contains some of the actual NAs.
If you are using R (like it seems) the naniar and the imputeTS packages offer nice functions for missing data visualizations.
Some examples from the naniar package, which is especially good for multivariate data (more plot examples):
Some examples from the imputeTS package, which is especially good for time series data (additional plot examples):
I have a time series dataframe like blow, and the number in it is meaning less, and I have some problems when applying LSTM.
I have saw some demos of LSTM, mostly use this pattern: [y_{t-2},y_{t-1},y_{t}] to predict [y_{t+1}], but just as the dataframe blow, I also have featureA, featureB, featureC, so my quesiton is: how to use multi inputs or multi features for LSTM
time featureA featureB featureC target
1 2 5 6 1
2 4 1 7 3
3 6 2 1 5
4 2 4 0 7
5 7 6 1 5
6 9 3 2 8
7 1 2 3 5
8 2 9 5 10
9 1 10 7 6
10 3 2 2 11
For RNN/LSTM, it is more like this: [..., y_{t-2}(x_{t-2}), y_{t-1}(x_{t-1})] to predict [y_{t}(x_{t})]
Or more succinctly:
y_{t} = f(y_{t-1}, x_{t})
So in feed forward you still use your inputs x_{t} (i.e. your features) plus the outputs from previous timesteps to make the prediction at the current timestep.
I am trying to calculate points in a Formula 1 racing league. I'm having trouble with a bonus 15 points if a constructor qualifies 1st and finishes the race 1st. The issue is there could be two different drivers who do this. For example. As you can see, HAM qualified 1st and ROS finished 1st in the race. Because they both drive for Mercedes, 15 points need to be awarded to Mercedes. The data can't be moved around as it's imported using an API (not in the example) but a copy of the layout can be found here
Qualifying Race Driver Team
14 1 ROS mercedes
1 15 HAM mercedes
3 3 VET ferrari
8 4 RIC red_bull
6 5 MAS williams
19 6 GRO haas
10 7 HUL force_india
16 8 BOT williams
7 9 SAI toro_rosso
5 10 VES toro_rosso
13 11 PAL renault
Put this in I2 and copy down. See if that is how you want it:
=IF(AND(VLOOKUP(1, $A$2:$H$12, 8, FALSE)=VLOOKUP(1, $B$2:$H$12, 7, FALSE), VLOOKUP(1, $B$2:$H$12, 7, FALSE)=H2, MATCH(H2, H:H, 0)=ROW(H2)), 15, 0)
I know that tensors have an apply method, but this only applies a function to each element. Is there an elegant way to do row-wise operations? For example, can I multiply each row by a different value?
Say
A =
1 2 3
4 5 6
7 8 9
and
B =
1
2
3
and I want to multiply each element in the ith row of A by the ith element of B to get
1 2 3
8 10 12
21 24 27
how would I do that?
See this link: Torch - Apply function over dimension
(Thanks to Alexander Lutsenko for providing it. I just moved it to the answer.)
One possibility is to expand B as follow:
1 1 1
2 2 2
3 3 3
[torch.DoubleTensor of size 3x3]
Then you can use element-wise multiplication directly:
local A = torch.Tensor{{1,2,3},{4,5,6},{7,8,9}}
local B = torch.Tensor{1,2,3}
local C = A:cmul(B:view(3,1):expand(3,3))