Remove zero rows and columns from a matrix

Remove zero rows and columns from a matrix - Messages

#1 Posted: 4/19/2021 10:44:50 PM
Rodolfo Cruz Vargas

Rodolfo Cruz Vargas

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Hello
I am new to the use of Smath Studio, and I started by calculating the solution of a frame through the method of rigidities, the issue is that when carrying out the calculations I need to calculate a reduced matrix. For this I need to remove the rows and columns that contain zeros. I use the following function but it gives me an error, someone knows how to solve it

foro.png
#2 Posted: 4/20/2021 2:59:54 AM
overlord

overlord

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Wrote

Hello
I am new to the use of Smath Studio, and I started by calculating the solution of a frame through the method of rigidities, the issue is that when carrying out the calculations I need to calculate a reduced matrix. For this I need to remove the rows and columns that contain zeros. I use the following function but it gives me an error, someone knows how to solve it


I don't know if there is a ready function but you can use the one I wrote myself.
You can either remove zero rows and columns manually or with a function.
With posted function you can not perform removal if matrix elements are text.

Regards

removezeros.sm (11 KiB) downloaded 34 time(s).

removezeros.png
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Andrey Ivashov 4/20/2021 5:39:00 AM
#3 Posted: 4/20/2021 4:47:25 AM
sergio

sergio

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Overlord forgot to tell you that the two functions it used in its function, as well as the one you used to no avail (nonZeroRorwsCols (R)), is part of an external plugin (MatrixExtensions). Could it be that you haven't loaded the plugin? because it works correctly for me.
Until recently I myself did not know its existence since here in the forum (in English) I do not think it is reviewed. Maybe it is in the Russian-language forum.
SMathStudio_Desktop_E4l6s0W15L.png
sergio
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Andrey Ivashov 4/20/2021 5:39:00 AM
#4 Posted: 4/20/2021 8:30:53 AM
NDTM Amarasekera

NDTM Amarasekera

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Function 'nonZerosRowsCols".
I get an error and invalid answers as shown, apparently when some non-zero values have decimals.

nonZerosRowsCols.png
Look within!... The secret is inside you. Best Regards Eng. NDTM Amarasekera - Sri Lanka
#5 Posted: 4/20/2021 8:42:13 AM
Jean Giraud

Jean Giraud

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... for that particular example.

Minor.PNG
#6 Posted: 4/20/2021 9:09:51 AM
Davide Carpi

Davide Carpi

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Another way

rmEmptyRC.sm (7 KiB) downloaded 37 time(s).

2021-04-20 16_02_29-SMath Studio - [rmEmptyRC.sm].png
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#7 Posted: 4/20/2021 10:12:50 AM
sergio

sergio

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attention Davide, in the first 'if' one of the two 'max' is a 'min'

sergio

OK has been corrected (do not consider this message)

sergio
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Davide Carpi 4/20/2021 11:03:00 AM
#8 Posted: 4/20/2021 11:08:17 AM
Davide Carpi

Davide Carpi

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Wrote

attention Davide, in the first 'if' one of the two 'max' is a 'min'

sergio



TY, updated. Just shown the idea to have it working using the built-in features.





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#9 Posted: 4/20/2021 1:01:58 PM
Jean Giraud

Jean Giraud

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... alternately: brute force works well.
It has very many applications for purpose.
Take care all Collabs ... Jean

Page28 BruteForce.sm (13 KiB) downloaded 31 time(s).
#10 Posted: 4/20/2021 5:02:18 PM
Alvaro Diaz Falconi

Alvaro Diaz Falconi

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Hi. normi (infinitum norm) take the maximum of the absolute values of a matrix. max and min are defined only for reals, but a version with normi will work with complex numbers too. With the technique from Davide applied to the overlod method, it works also for empty answers.

Clipboard02.jpg

rmEmptyRC.sm (8 KiB) downloaded 35 time(s).

Best regards.
Alvaro.
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sergio 4/21/2021 6:39:00 AM
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