Community Profile # stelios loizidis

Last seen: 18 jours ago Active since 2019

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Question

Find similar values from different tables
Hello. I have two matrices, the A1 (270X1) and the A2 (171X1). Matrix A2 has some values, which are the same as some of matrix ...

27 jours ago | 1 answer | 0

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Question

Replace number with text
Hello, I have the following problem. I have a matrix A which has dimensions of 300x350. In this matrix I want to replace the val...

environ un mois ago | 2 answers | 0

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Question

Replace values ​​in a matrix
Hello. I have the following problem. I have a matrix A with dimensions 1X72. I want in matrix B to have the mean per 24 values....

3 mois ago | 1 answer | 0

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How do I find the number of hours?
Another question I have is if I have table A but the available data are as follows: 1/2/2014 01:00, 4/5/2014 05:00, 6/8/2014 16:...

3 mois ago | 0

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How do I find the number of hours?
Hello, I have a matrix A with dimensions 35000X1 (datetime). There are hours in matrix A. For example, 01:00, 05:00, 17:00, 23...

3 mois ago | 3 answers | 0

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Question

MAE and RMSE in percentage
Hello, I have the following question: I want to calculate the MAE and RMSE in percentage. The following code gives the correct ...

3 mois ago | 1 answer | 0

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Question

How do I find the corresponding dates for maximum prices?
Hello. I have a matrix A with dimensions 366x24 which contains values and a matrix B which contains dates-time (366x24 datetime)...

7 mois ago | 1 answer | 0

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Question

How do I read (hours) data from the .xlsx file?
Hello, I have the following issue. In a .xlsx file I have in column D hours (format: 00: 00: 00,01: 00: 00, ... 23:00:00). How ...

9 mois ago | 2 answers | 0

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Question

Separate datasets into months
Hello,I have the Data matrix (1X1744) which contains values for two years (2014-2015) and Time (1X1744) is datetime contains the...

9 mois ago | 1 answer | 0

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Question

Multiplication between matrices with different dimensions
Hello. I have the following issue: I have the matrix H which has a size of 353X25. Next I calculate the pseudo-inverse H_inv (25...

10 mois ago | 1 answer | 0

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Question

Save values from iterations
for r=1:5 for w=1:100 Datax(r,:)=(W'*NewDatax(r,:)')'; % size: NewDatax 5X70 ntempDatax=Datax+b; Values(r,:)=ntempData...

10 mois ago | 0 answers | 0

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Question

Hello. I have the following problem: I have a matrix A (3x3), and I want to add elements to this matrix and create table B wit...

10 mois ago | 1 answer | 0

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Question

Placing data in a matrix
Hello I have the following problem: I have a matrix A (12708X1). I want to put the data of matrix A in a matrix B which has siz...

10 mois ago | 1 answer | 0

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Question

Import hours from a excel file
Hello, in a excel file I have 24 values in the first column and in the second column I have the corresponding hours (format of h...

10 mois ago | 1 answer | 0

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Question

How to select specific data from one matrix and place it in another
Hello, I have the following problem. I have a large matrix A (1X960). At positions 336 I have the prices for 14 consecutive Mon...

12 mois ago | 3 answers | 0

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Question

Comparison of specific values from the same matrix
Hello. I have the following problem: I have a table Z (1X100). The first value is always zero. I want to find among the other v...

environ un an ago | 1 answer | 0

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Question

How the results are stored in a .xlsx file?
Hello, I have the following problem: I want to calculate the RMSE. More specifically I run the algorithm five times and then ad...

environ un an ago | 1 answer | 0

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Question

Save data from for-loop and their use
Hello, I have the following problems. I have matrices: SatTrDatax_Norm (4X200) and SatTrDatay_Norm (4x50). I want to apply wave...

environ un an ago | 1 answer | 0

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Question

How to run a code several times using a for loop
Hello, I have the following problem: I want to run the following code for 50 interations, and saving the values of matrix A1, B...

plus d'un an ago | 2 answers | 0

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Question

Select the correct data from matrix
Hello. I have the following problem: For a product I predict the prices it will have the next day (24 prices). I use 5 models to...

plus d'un an ago | 1 answer | 0

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Question

Data comparison and selection the smallest
Hello. I have a matrix A which has size of 24X5. I want each row in matrix A to be selected the smallest and stored in matrix B....

plus d'un an ago | 2 answers | 0

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Question

Create a matrix through replacement, from another matrix
Hello. I have a matrix A (5X5) and I want to create a matrix B (of the same size as A) and its values come from matrix A. Also, ...

plus d'un an ago | 1 answer | 0

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Question

Create a matrix with values in a specific position from another matrix
Hello, I have a matrix with hourly prices for a product. That, is 24 prices for one day. Also, these prices are for one month. I...

plus d'un an ago | 1 answer | 0

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Question

Forecasting Prices with Learning Machine
Hello. I am new to Learning machine development. In short, I want to do the following: I have some product prices for 216 and I ...

plus d'un an ago | 0 answers | 0

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Question

Price forecasting using ARIMA Model
Hello, I have this theme: I want to forecast market prices using ARIMA models. For example I have ARIMA1(1,1,4), ARIMA2(0,1,1) ...

plus d'un an ago | 1 answer | 0

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Question

Remove random columns from a big matrix?
Hello, I have this issue: I want to randomly remove 3000 columns from a big matrix with size 1600X8500. below I have a code I w...

environ 2 ans ago | 2 answers | 0

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Question

How will I reduce the time it takes to calculate data?
Hello. In an excel file I put some data and then I creared a big matrix (1200X2000) on Matlab based on this data. Then I took ...

plus de 2 ans ago | 1 answer | 0

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Question

finding data from a big matrix
Hello, I have the followin question: I have a big matrix A (1140X837).With help of Matlab I calculated the following data [av ...

plus de 2 ans ago | 0 answers | 0

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Question

Calculate a matrix through a for loop
Hello, I have the following code to which I am trying to find variable B. Veriable B is a matrix that will include the data in ...

plus de 2 ans ago | 0 answers | 0