《计算机应用基础》课程教学资源（参考资料）MATLAB Reference Sheet, by Giordano Fusco & Jindich Soukup.pdf_大学文库

CS 412 UW-Madison MATLAB Reference Sheet created by modified by Giordano Fusco Jindich Soukup version 18-02-12 Useful workspace functions (help general) help obtain help generally or for a specific function lookfor obtain one-line help if it exists more toggles pagination, useful for longs “helps” load read variables from a file save save all or selected variables to a file Variable types The basic variable type is a two-dimensional array of doubles (64- bit representation). Scalar is a 1 × 1 array. Row vector of length n is a 1 × n array. Column vector of length m is an m × 1 array. Matrix of dimensions m rows and n columns is an m × n array. Cell is collection of data with different variable types and sizes. (doc cell) Struct is structure array with the specified fields and values. (doc struct String contain text. (help strfun) Variable name conventions MATLAB is case sensitive. A variable must start with a letter (A-Z, a-z). Up to 63 (namelengthmax) letters, digits and underscores. Default variables/constants (help elmat) ans result of last unassigned calculation eps smallest number that can be added to 1.0 and still be different flops count of floating point operations Inf infinity, e.g. 1/0 = Inf NaN Not a Number, e.g. 0/0 = NaN pi value of π (3.1415 . . .) i, j √ −1 realmax largest real number MATLAB can represent realmin smallest real number MATLAB can represent Avoid also the keywords (testing with iskeyword()) and buildin functions (testing with which -all name of variable or by help name of variable). About user variables (help elmat,help general) clear clear all or selected variables (or functions) from the current workspace length length of a vector or maximum dimension of an array size display dimensions of a particular array Punctuation (help punct), . decimal point, e.g. 325/100, 3.25 and .325e1 are equivalent; accessing internal variables of struct ... three or more decimal points at the end of a line cause the following line to be a continuation , comma is used to separate matrix elements and arguments to functions, also used to separate statements in multistatement lines ; used inside brackets to indicate the ends of the rows of a matrix, also used after an expression or statement to suppress printing % begins comments ’ quote. ’ANY TEXT’ is a vector whose components are the ASCII codes for the characters. A quote within the text is indicated by two quotes, e.g. ’Don’’t forget.’ () grouping in expressions, indexing of matrices and strings, argument of function [] creating of matrix, concatenation of strings {} creating of cells, indexing of cells Explicit matrix creation Elements in a row can be delimited by a comma or a space. Explicit assignment using ;’s to end rows a = [1,2,3;4,5,6;7,8,9] Explicit assignment using “newline” to end rows a = [1,2,3 4,5,6 7,8,9] Explicit assignment using continuation lines b = [1 2 3 4 5 6 ... 7 8 9 10] Vector/Matrix initialization (help elmat) linspace(a,b,N) linearly spaced intervals between a and b (inclusive) comprised of N points zeros(m,n) an m by n array of zeroes zeros(n) an n by n array of zeroes ones(m,n) an m by n array of ones ones(n) an n by n array of ones eye(m,n) an m by n array with ones on the diagonal eye(n) an n by n identity matrix ones(n) an n by n array of ones rand(m,n) an m by n array of random numbers rand(n) an n by n array of random numbers List generation/variable indexing Indexing from 1. i:k:l list generation: 1stV alue : Stride : LastV alue v(1) 1st element of vector v v(end) last element of vector v v(1:2:9) 1st, 3rd, 5th, 7th, 9th elements of vector v v(2:3:9) 2nd, 5th, 8th elements of vector v A(2,3) 2’nd row, 3’rd column of matrix A A(:,3) all elements in column 3 A(1,:) all elements in row 1 A(1:2:end,:) all odd rows of matrix A A(1:2,2:4) sub-matrix of rows 1 and 2, columns 2 through 4 A(1,end) last element in 1’st row

Vector/Matrix op’s (help arith, help ops) + addition - subtraction * multiplication .* point-wise multiplication / left division ./ point-wise left division \ right division .\ point-wise right division b exponentiation .b point-wise exponentiation ’ complex conjugate transpose .’ transpose Loops (help lang) for k = vectorOrColumnList % MATLAB statements end while logicalExpression % MATLAB statements end Note that MATLAB is an interpreted language, and hence loops are slower than internal vector manipulation function. So it is better to avoid loops whenever possible. if/elseif/else construct (help lang) if logicalExpression1 % Mandatory % MATLAB statements elseif logicalExpression2 % Optional % MATLAB statements elseif logicalExpression3 % Optional . . elseif logicalExpressionN % Optional % MATLAB statements else % Optional % MATLAB statements end % Mandatory Logical operators (help relop) greater than >= greater than or equal == equal ∼= not equal & logical AND | logical OR ∼ logical NOT && short-circuit logical AND || short-circuit logical OR Script M-files Sequences of MATLAB commands can be stored in text files with the extension .m. The commands can be executed by typing the name of the files (without the extension) or through the file management tools provided by the Command Window menu. Function M-files Define a separate file called functionName.m with the following form: function [out1,...,outN] = functionName (in1,...inM) % functionName: A brief one line description (optional) % . % . % More description (optional) % . % . % First executable statement . . % Valid executable MATLAB statements and comments . . % Last line The function call is made with the following statement: [out1,out2,...,outN] = functionName (in1,in2,...inM) Useful in M-files (help general, help lang) disp display a string fprintf write data to screen of file echo toggle command echo error display message and abort input prompt for input keyboard transfer control to keyboard pause wait for time or user response return return to caller warning display warning messages Figure window control (help graphics) clc clear the command window clf clear the figure window figure start a new figure window figure(n) make figure with index n active. If n is an integer and figure(n) does not exist, create it close close current figure window close(n) close figure with index n print -dpdf fileName.pdf save the current figure in a pdf file Plotting (help graph2d, help graph3d) plottoolsopen plotting GUI contour contour plot on a plane contour3 3-D contour plot with displayed depth mesh 3-D mesh surface meshc combination mesh/contour plot meshz 3-D mesh with curtain pcolor pseudocolor (checkerboard) plot plot basic 2D plots plot3 plot lines and points in 3-D space surf 3-D colored surface surfc combination surf/contour plot surfl 3-D shaded surface with lighting semilogx plot with logarithmic x axis loglog plot with both x and y axes logarithmic Plotting annotation (help graph2d, graph3d) clabel contour plot elevation labels colorbar display color bar (color scale) legend graph legend title graph title xlabel x-axis label ylabel y-axis label