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Matrix

As a scientific programming language, all the usual matrix operations are supported by Hedgehog Script. The matrix is a two-dimensional array of numbers. The matrix is created by the mat() function or Mat() class constructor.

Create a matrix​

You can create a matrix by the mat() function or Mat() class constructor. The mat() function is a shortcut (or a wrapper function) for the Mat() class constructor.

The Mat() class constructor accept the following arguments:

Mat(input: number[][] | number[] | number)

param input - the input data for the matrix, which means you can create a matrix by passing a two-dimensional array of numbers(as an M-by-N matrix), a one-dimensional array of numbers(as a 1-by-N matrix), or a single number(as a 1-by-1 matrix).

the mat() function and Mat() class constructor have the same parameters, but the mat() function is more convenient to use.

Here is an example of creating a matrix by the mat() function and Mat() class constructor:

Create certain types of matrix with built-in functions​

Also here are a list of built-in functions for creating certain types of matrix:

csv2mat(csv: string): Mat - create a matrix from a CSV string

mat2csv(mat: Mat): string - create a CSV string from a matrix

json2mat(json: string): Mat - create a matrix from a JSON string

mat2json(mat: Mat): string - create a JSON string from a matrix

zeros(m: number, n?: number): Mat - create an m-by-m or m-by-n matrix of zeros

ones(m: number, n?: number): Mat - create an m-by-m or m-by-n matrix of ones

Ns(m: number, n?: number, N:number): Mat - create an m-by-m or m-by-n matrix of given number N

diag(v: number[]): Mat - create a diagonal matrix from a vector

eye(m: number, n?: number): Mat - create an m-by-m or m-by-n identity matrix

random(m: number, n?: number): Mat - create an m-by-m or m-by-n matrix of random numbers

range(start: number, end = null, step?: number): Mat - create a 1-by-N matrix of numbers from start to end with a step.

  • range(x) - create a 1-by-x matrix of numbers from 0 to x-1
  • range(x, y) - create a 1-by-(y-x) matrix of numbers from x to y-1
  • range(x, y, z) - create a 1-by-ceil((y-x)/z) matrix of numbers from x to y-1 with a step of z

Matrix operations​

Most of the matrix operations are supported and overloaded by Hedgehog Script, like the +, -, *, /, ** operators -- which means you can use the Matlab-flavored operators to do matrix operations and expressions.

Reference of Mat() class​

Here are the reference of Mat() class:

Member variables​

val: number[][] - the value (2D array of number) of the matrix

rows: number - the number of rows of the matrix

cols: number - the number of columns of the matrix

mode: string - the mode of the matrix, which can be:

  • 'gpu' (GPU acceleration)
  • 'cpu' or null (CPU mode)
  • 'wasm' (wasm mode)

digits - the number of digits to display when printing the matrix

Member functions​

clear() - clear the matrix

clone() : Mat - clone the current matrix

copy(mat: Mat) - copy the value of another matrix to the current matrix

equals(mat: Mat): boolean - check if the current matrix is equal to another matrix

init(input: number[][]): Mat - initialize the matrix

min(): number - get the minimum value of the matrix

max(): number - get the maximum value of the matrix

range(arg1: number, arg2: number|null, step = 1): Mat - create a 1-by-N matrix of numbers from arg1 to arg2 with a step.

Ns(row: number, col: number, N: number): Mat - set the value of the matrix to a given number N

zeros(row: number, col: number): Mat - set the value of the matrix to zeros

ones(row: number, col: number): Mat - set the value of the matrix to ones

diag(v: number[]): Mat - set the value of the matrix to a diagonal matrix from a vector

eye(row: number, col: number): Mat - set the value of the matrix to an identity matrix

random(row: number, col: number): Mat - set the value of the matrix to a matrix of random numbers

T(): Mat - transpose the matrix

transpose(): Mat - transpose the matrix

each(functor: (element:number) => number): Mat - apply a functor to each element of the matrix

add(mat: Mat): Mat - add another matrix to the current matrix

addScalar(scalar: number): Mat - add a scalar to the current matrix

minus(mat: Mat): Mat - subtract another matrix from the current matrix

multiply(mat: Mat): Mat - multiply another matrix to the current matrix

multiplyScalar(scalar: number): Mat - multiply a scalar to the current matrix

minusScalar(scalar: number): Mat - subtract a scalar from the current matrix

dotMultiply(mat: Mat): Mat - dot multiply another matrix to the current matrix

divide(mat: Mat): Mat - divide the current matrix by another matrix

set(row: number, col: number, value: number): Mat - set the value of a given element of the matrix

get(row: number, col: number): number - get the value of a given element of the matrix

at(row: number, col: number): number - get the value of a given element of the matrix

to2DArray(): number[][] - convert the matrix to a 2D array of number

row(row: number): Mat - get a row of the matrix as an N-by-1 matrix

col(col: number): Mat - get a column of the matrix as an 1-by-N matrix

reshape(row: number, col: number): Mat - reshape the matrix to a given size

subMatrix(rowStart: number, rowEnd: number, colStart: number, colEnd: number): Mat - get a sub-matrix of the current matrix

resize(row: number, col: number, defaultFillingValue = 0): Mat - resize the matrix to a given size

Rows(rowStart: number, rowEnd: number): Mat - get a sub-matrix of the current matrix

Cols(colStart: number, colEnd: number): Mat - get a sub-matrix of the current matrix

ColVector(col: number): Mat - get a column of the matrix as an 1-by-N matrix

Row(row: number): Mat - get a row of the matrix as an N-by-1 matrix

Col(col: number): Mat - get a column of the matrix as an 1-by-N matrix

squareSum(): number - get the square sum of the matrix

setDigits(digits: number): Mat - set the number of digits to display when printing the matrix

toString(): string - convert the matrix to a string

toStirngWithTab(): string - convert the matrix to a string with tab

toCsv(): string - convert the matrix to a csv string

toJson(): string - convert the matrix to a json string

toTex(): string - convert the matrix to a tex string

log(): Mat - print the object in the console terminal (for debugging)

appendInRow(mat: Mat): Mat - append another matrix in the row of the current matrix

appendInColumn(mat: Mat): Mat - append another matrix in the column of the current matrix