mat | R demo package illustrating BLAS and LAPACK calls

 by   cjgeyer R Version: Current License: Non-SPDX

kandi X-RAY | mat Summary

kandi X-RAY | mat Summary

mat is a R library. mat has no bugs, it has no vulnerabilities and it has low support. However mat has a Non-SPDX License. You can download it from GitHub.

this is an r package that is a demo for statistical confusing classes about how to call blas and lapack routines to do numerical linear algebra in c code called from r. the name of the git repo is different from the name of the r package because the package used to be called mat and was renamed baz to avoid a conflict with cran, not that we intend to put the package on cran but r cmd check --as-cran does more checks, so we want to pass that too. it is just a demo, it doesn't show how to use all blas and linpack routines (only a few of them, but if you can figure out how to call one, then you can figure out how to call the rest). thus all the interesting stuff in this package is in the src directory of the package, which contains the files. everything else is just junk that surrounds this with an r package so it can get exercised. the examples in the help pages and in the tests directory of the package show that the code works. if the package is checked with. valgrind does not complain. (actually, by default, it complains a lot, but all of the complaints are about c function wcsrtombs, which is not in our code, not even in the code of r, but in the c standard
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              mat has a low active ecosystem.
              It has 14 star(s) with 3 fork(s). There are 4 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              mat has no issues reported. There are no pull requests.
              It has a neutral sentiment in the developer community.
              The latest version of mat is current.

            kandi-Quality Quality

              mat has 0 bugs and 0 code smells.

            kandi-Security Security

              mat has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              mat code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              mat has a Non-SPDX License.
              Non-SPDX licenses can be open source with a non SPDX compliant license, or non open source licenses, and you need to review them closely before use.

            kandi-Reuse Reuse

              mat releases are not available. You will need to build from source code and install.
              Installation instructions are not available. Examples and code snippets are available.

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            Community Discussions

            QUESTION

            OpenCV numpy to cv::Mat conversion
            Asked 2022-Apr-05 at 12:36

            I inherited an application with opencv, shiboken and pyside and my first task was to update to qt6, pyside6 and opencv 4.5.5. This has gone well so far, I can import the module and make class instances etc. However I have a crash when passing numpy arrays:

            I am passing images in the form of numpy arrays through python to opencv and I am using pyopencv_to to convert from the array to cv::Mat. This worked in a previous version of opencv (4.5.3), but with 4.5.5 it seems to be broken.

            When I try to pass an array through pyopencv_to, I get the exception opencv_ARRAY_API was nullptr. My predecessor solved this by directly calling PyInit_cv2(), which was apparently previously included via a header. But I cannot find any header in the git under the tag 4.5.3 that defines this function. Is this a file that is generated? I can see there is a pycompat.hpp, but that does not include the function either.

            Is there a canonical way to initialize everything so that numpy arrays can be passed properly? Or a tutorial anyone can point me to? My searches have so far not produced any useful hints.

            Thanks a lot in advance! :)

            ...

            ANSWER

            Answered 2022-Apr-05 at 12:36

            I finally found a solution. I dont know if this is the correct way of doing it, but it works.

            I made a header file that contains

            Source https://stackoverflow.com/questions/71690714

            QUESTION

            Reading large .mat file in R
            Asked 2022-Mar-20 at 01:38

            I am trying to read a large matrix into R. The matrix has dimensionality: 3'987'288 x 93 and is about 3GB large. (Class = double) It is saved as a .mat file (it is not a v7.3 .mat file)

            I tried to read the matrix with the R.matlab package:

            ...

            ANSWER

            Answered 2022-Mar-20 at 01:38

            Apparently V7.3 is not the only incompatible mat file version. As stated in the RDocuments,

            readMat: Reads a MAT file structure from a connection or a file Description

            Reads a MAT file structure from a connection or a file. Both the MAT version 4 and MAT version 5 file formats are supported.

            And long story short, version 4 and version 5 cannot save such large dataset in one file. I think at least 2 solutions are straight forward:

            1. Exchange data in a different file format, e.g. HDF5 or SQlite. Such files are well supported both in R and matlab and do not have the compatibility issue.

            2. Save mat file in matlab in version 4 with the '-v4' switch, but there is an upper size limit in version 4, so you'll likely need to split you data across multiple files.

            Source https://stackoverflow.com/questions/71524856

            QUESTION

            How to change matrix entries using conditional if in R
            Asked 2022-Mar-15 at 23:18

            I have this example matrix and I want to change the entries of the matrix with "YES" or "NO" based on a conditional if statement.

            ...

            ANSWER

            Answered 2021-Sep-04 at 15:25

            You do not need loops here. Just use the whole matrix in your call to x>5

            Source https://stackoverflow.com/questions/68791007

            QUESTION

            Average values over all offset diagonals
            Asked 2022-Mar-07 at 12:34

            I'm trying to compute average values of shifted diagonals of a square array.

            Given input matrix like (in reality much larger than 3x3):

            ...

            ANSWER

            Answered 2022-Mar-05 at 16:03

            The tricky part is summing the diagonals. I've questioned multiple times in the past about the fastest approach to accomplish this.

            One solution is to use bincount:

            Source https://stackoverflow.com/questions/71362928

            QUESTION

            How to replace 0s in a matrix with a pre-specified value
            Asked 2021-Dec-27 at 19:17
            mat <- diag(3)
            > mat
                 [,1] [,2] [,3]
            [1,]    1    0    0
            [2,]    0    1    0
            [3,]    0    0    1
            
            ...

            ANSWER

            Answered 2021-Dec-27 at 18:53

            QUESTION

            Is it possible to use a collection of hyperspectral 1x1 pixels in a CNN model purposed for more conventional datasets (CIFAR-10/MNIST)?
            Asked 2021-Dec-17 at 09:08

            I have created a working CNN model in Keras/Tensorflow, and have successfully used the CIFAR-10 & MNIST datasets to test this model. The functioning code as seen below:

            ...

            ANSWER

            Answered 2021-Dec-16 at 10:18

            If the hyperspectral dataset is given to you as a large image with many channels, I suppose that the classification of each pixel should depend on the pixels around it (otherwise I would not format the data as an image, i.e. without grid structure). Given this assumption, breaking up the input picture into 1x1 parts is not a good idea as you are loosing the grid structure.

            I further suppose that the order of the channels is arbitrary, which implies that convolution over the channels is probably not meaningful (which you however did not plan to do anyways).

            Instead of reformatting the data the way you did, you may want to create a model that takes an image as input and also outputs an "image" containing the classifications for each pixel. I.e. if you have 10 classes and take a (145, 145, 200) image as input, your model would output a (145, 145, 10) image. In that architecture you would not have any fully-connected layers. Your output layer would also be a convolutional layer.

            That however means that you will not be able to keep your current architecture. That is because the tasks for MNIST/CIFAR10 and your hyperspectral dataset are not the same. For MNIST/CIFAR10 you want to classify an image in it's entirety, while for the other dataset you want to assign a class to each pixel (while most likely also using the pixels around each pixel).

            Some further ideas:

            • If you want to turn the pixel classification task on the hyperspectral dataset into a classification task for an entire image, maybe you can reformulate that task as "classifying a hyperspectral image as the class of it's center (or top-left, or bottom-right, or (21th, 104th), or whatever) pixel". To obtain the data from your single hyperspectral image, for each pixel, I would shift the image such that the target pixel is at the desired location (e.g. the center). All pixels that "fall off" the border could be inserted at the other side of the image.
            • If you want to stick with a pixel classification task but need more data, maybe split up the single hyperspectral image you have into many smaller images (e.g. 10x10x200). You may even want to use images of many different sizes. If you model only has convolution and pooling layers and you make sure to maintain the sizes of the image, that should work out.

            Source https://stackoverflow.com/questions/70226626

            QUESTION

            Haskell: Can I read integers directly into an array?
            Asked 2021-Dec-05 at 11:40

            In this programming problem, the input is an n×m integer matrix. Typically, n≈ 105 and m ≈ 10. The official solution (1606D, Tutorial) is quite imperative: it involves some matrix manipulation, precomputation and aggregation. For fun, I took it as an STUArray implementation exercise.

            Issue

            I have managed to implement it using STUArray, but still the program takes way more memory than permitted (256MB). Even when run locally, the maximum resident set size is >400 MB. On profiling, reading from stdin seems to be dominating the memory footprint:

            Functions readv and readv.readInt, responsible for parsing integers and saving them into a 2D list, are taking around 50-70 MB, as opposed to around 16 MB = (106 integers) × (8 bytes per integer + 8 bytes per link).

            Is there a hope I can get the total memory below 256 MB? I'm already using Text package for input. Maybe I should avoid lists altogether and directly read integers from stdin to the array. How can we do that? Or, is the issue elsewhere?

            Code ...

            ANSWER

            Answered 2021-Dec-05 at 11:40

            Contrary to common belief Haskell is quite friendly with respect to problems like that. The real issue is that the array library that comes with GHC is total garbage. Another big problem is that everyone is taught in Haskell to use lists where arrays should be used instead, which is usually one of the major sources of slow code and memory bloated programs. So, it is not surprising that GC takes a long time, it is because there is way too much stuff being allocation. Here is a run on the supplied input for the solution provided below:

            Source https://stackoverflow.com/questions/70143678

            QUESTION

            Why does KNeighborsClassifier always predict the same number?
            Asked 2021-Oct-17 at 14:23

            Why does knn always predict the same number? How can I solve this? The dataset is here.

            Code:

            ...

            ANSWER

            Answered 2021-Oct-17 at 07:36

            TL;DR
            It have to do with the StandardScaler, change it to a simple normalisation.
            e.g.

            Source https://stackoverflow.com/questions/69599448

            QUESTION

            Angular mat-form-filed input disable autocomplete
            Asked 2021-Sep-22 at 16:08

            I am using angular material for all my controls. We have a requirement to disable auto-complete so that any previously typed value will not show up. I have my code as below. I tried autocomplete "off" "disabled" and other suggestions that I found online. But nothing seems to work.

            ...

            ANSWER

            Answered 2021-Sep-15 at 22:48

            In the past, many developers would add autocomplete="off" to their form fields to prevent the browser from performing any kind of autocomplete functionality. While Chrome will still respect this tag for autocomplete data, it will not respect it for autofill data.

            One workaround is to put an unknown value in the autocomplete,

            .

            When testing this it worked for me most of the time, but for some reason didn't work anymore afterwards.

            My advise is not to fight against it and use it's potential by properly using the autocomplete attribute as explained here.

            Source https://stackoverflow.com/questions/69119646

            QUESTION

            Angular styles from styles.scss are not always being applied
            Asked 2021-Sep-17 at 14:51

            I added a few CSS properties to different mat-buttons on my Angular 12 based website. In order to not accidentally apply these properties to all mat-buttons, but only to the ones I want to apply them to, I added a class to the buttons and used it to set the CSS properties like this:

            Component html file:

            ...

            ANSWER

            Answered 2021-Sep-17 at 14:31

            Those styles are rewritten. Use !important:

            styles.scss:

            Source https://stackoverflow.com/questions/69225021

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