https://github.com/kovacsgg/mat4js

JavaScript library to load Matlab Level 5 MAT-files as JavaScript objects and vice versa
https://github.com/kovacsgg/mat4js

javascript javascript-library mat-files matlab

Last synced: about 1 month ago
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JavaScript library to load Matlab Level 5 MAT-files as JavaScript objects and vice versa

• Host: GitHub
• URL: https://github.com/kovacsgg/mat4js
• Owner: KovacsGG
• License: gpl-3.0
• Created: 2020-07-20T21:25:06.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-10-01T13:50:43.000Z (3 months ago)
• Last Synced: 2024-12-09T07:43:47.498Z (about 1 month ago)
• Topics: javascript, javascript-library, mat-files, matlab
• Language: JavaScript
• Homepage:
• Size: 762 KB
• Stars: 21
• Watchers: 2
• Forks: 3
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# mat4js

JavaScript library to load Matlab Level 5 MAT-files as JavaScript objects.

Based on the documentation: https://www.mathworks.com/help/pdf_doc/matlab/matfile_format.pdf released for 2019b

## Installation

### via npm

```

$ npm install mat-for-js

```

then use as

```js

import { read as readmat } from "mat-for-js"

readmat(ArrayBuffer)

```

```js

import * from "mat-for-js"

mat4js.read(ArrayBuffer)

```

### via script tag

Download `dist/mat4js.read.min.js` to your webserver and include it in your HTML:

```html

```

## Read

Use `mat4js.read(ArrayBuffer)`.

It returns a JavaScript object with a `.header` and `.data` property.

#### `.header`

contains 116 bytes of text.

Padding characters are not truncated.

#### `.data`

is an object containing the named arrays in the file. (`{name: content}`)

Matlab stores vectors as 2D but flat arrays (1xn or nx1). These are converted to plain 1D arrays (`[1, 2, 3]` instead of `[[1, 2, 3]]`) or strings in case of character arrays. In multidimensional character arrays the characters are not concatenated to form strings, but are kept separate. (`{char_array: [["a", "b", "c"], ["d", "e", "f"]]}` instead of `{char_array: ["abc", "def"]}`)

Numeric arrays with `Int64` or `Uint64` data types are converted into an array of `BigInt`.

Numeric arrays with imaginary component are converted into an array of objects with `.r` and `.i` properties for the real and imaginary components respectively.

Scalar structs are converted into objects as would be expected, while non-scalar structs are more akin to cell arrays. For a struct constructed with

```

S = struct()

S.cell = {1 2; 3 4}

S.fruit = 'apple'

```

In JavaScript

```js

S.cell[1][0] == 3

S.fruit == "apple"

```

But for one constructed with `S = struct('cell', {1 2; 3 4}, 'fruit', 'apple')` (non-scalar):

```js

S[1][0].cell == 3

S[1][1].cell == 4

S[1][0].fruit == "apple"

S[1][1].fruit == "apple"

```

and `S.fruit == "apple"` is not accessible.

Sparse arrays are converted to objects with `.x` and `.y` properties describing the width and height of the array respectively, and an `.nz` property containing an array of objects representing non-zero values. These objects also have `.x` and `.y` properties for their indices in the matrix and an additional `.v` for the non-zero value at the index.

## Build

If you want to rebuild `dist/readmat.min.js`, first install the dev dependencies with `npm install`.  Once `webpack` is installed, run `npm run build`.

## Limitaions

There is no support for Object array types.  64-bit integer type support depends on using a version of JavaScript that includes the `DataView.getBigInt64()`/`DataView.getBigUint64()` methods.

Matlab v7.3 MAT-files use HDF5 data structure and are not supported. Reading such files will throw a `FeatureError` with the `.feature` property set to `"HDF5"`. There are other JavaScript projects to view HDF5 files: https://github.com/usnistgov/jsfive

There is no write functionality.