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In this article, the editor introduces in detail "what is the basic grammar of Octave", the content is detailed, the steps are clear, and the details are handled properly. I hope this article "what is the basic grammar of Octave" can help you solve your doubts.

Octave basic function generating matrix function

Eye (n): generate a unit matrix with n rows and n columns

Rand (nQuine m): randomly generate n rows and m columns of random numbers whose size ranges from 0 to 1.

Randn (m): generate random numbers with n rows and m columns according to Gaussian distribution

Ones (m): generate a matrix with n rows and m columns with elements of 1

Zeros (m): generate a matrix with n rows and m columns with zero elements.

Matrix operation function

B = A (nvir m): assign the values of rows n to m of matrix A to matrix B

A (nMagnem): take n rows and m columns of elements

A ([1 3],:): displays all the elements of the first and third rows of matrix A.

A (2): show all the elements in the second row of matrix A.

A = [A _ quotient B]: extend the base B to the right of matrix An and reassign the resulting new matrix to A.

A = [Aten B]: extend the basic B to the lower edge of the matrix An and reassign the resulting new matrix to A.

A (:): all the elements in An are sequentially formed into a new column vector in the direction of the column.

Reshape (A (i j), n, m): an is a column vector. I and j denote that the terms I to j of the column vector are taken out and reorganized into another matrix, and n and m are the corresponding rows and columns respectively.

Matrix operation

Multiplication of matrices

A. multiplib: multiply each element

A ^ 2: square the element

1.Compact a: reciprocal the elements of a.

Log (a): logarithm

Exp (a): take e as the base and an as the power

Abs (a): find the absolute value

V+ones (length (v), 1): add 1 to the elements of v

Transposition of Avalanche A

Prin (A): inverse or pseudo inverse

Sum (a): data summation in a matrix

Prod (a): product

Floor (a): round up

Ceil (a): round down

Max (A, [], 1): take the maximum value of each column

Max (A, [], 2): take the maximum value of each row

Max (max (A)): the maximum value in a matrix

Simple drawing

Plot (XMagol y): draw with x as Abscissa and y ordinate. The third parameter is optional, indicating the image type (the color of'r' is red).

Hold on: draw multiple pictures in the same image. Usage: first draw plot (tPowery1), then enter and exit hold on;, and then enter plot (trecovery2), that is, two images can be displayed simultaneously.

Xlabel (xString): xString represents the name of the x-axis

Ylabel (yString): yString represents the name of the y-axis

Legend (string1, string2 …) Name each curve according to the drawing order

Title (tString): tString represents the chart name

Print-dpng 'file.png': saves the chart as a png picture

Close: turn off the currently open chart

Figure (n): use this function before using the plot function to ensure that n is different and multiple chart windows can be opened without being overwritten.

Subplot (1): divide the drawing into 1 / 2 grids and use the first grid when drawing

Axis ([x1recovery2]): sets the scale value. [x1recovery2] is the scale range of the horizontal axis, and [y1recoery y2] is the scale range of the vertical axis.

Imagesc (A): draw a color graph matrix for matrix A, with different values corresponding to different color depths.

Common operation

PS1 ("> >"): change the command line leading symbol to "> >"

Size (A, [N]): an is a matrix. When the first parameter is omitted, the function returns an array [n < m], where n is the number of rows of An and m is the number of columns of A. the second parameter is optional, which represents the dimension of the matrix and returns the size of the Nth dimension. For example

A = 1 2 3 4 5 6 7 8 9size (A) = 9 1size (A Magi 1) = 9size (A Magi 2) = 1

Disp (): print a variable or string

Pwd: show current path

Load: loading data files

Who: query variable names in the work area

Whos: query the details of the work area

Clear: clear a variable (clear x). If there are no variables after clear, clear all variables.

Clc: clear the screen

Save file A: store the A matrix in the file file

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