R for matlab

RRRR forforforforMATLABMATLABMATLABMATLAB usersusersusersusers http://mathesaurus.sourceforge.net/octave-r.htmlhttp://mathesaurus.sourceforge.net/octave-r.htmlhttp://mathesaurus.sourceforge.net/octave-r.htmlhttp://mathesaurus.sourceforge.net/octave-r.html HelpHelpHelpHelp R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription help.start() doc help -i % browse with Info Browse help interactively help() help helpordoc doc Help on using help help(plot)or?plot help plot Help for a function help(package='splines') help splinesordoc splines Help for a toolbox/library package demo() demo Demonstration examples example(plot) Example using a function SearchingSearchingSearchingSearching availableavailableavailableavailable documentationdocumentationdocumentationdocumentation R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription help.search('plot') lookfor plot Search help files apropos('plot') Find objects by partial name library() help List available packages find(plot) which plot Locate functions methods(plot) List available methods for a function UsingUsingUsingUsing interactivelyinteractivelyinteractivelyinteractively R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription Rgui octave -q Start session source('foo.R') foo(.m) Run code from file history() history Command history savehistory(file=".Rhistory") diary on [..] diary off Save command history q(save='no') exitorquit End session OperatorsOperatorsOperatorsOperators R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription help(Syntax) help - Help on operator syntax ArithmeticArithmeticArithmeticArithmetic operatorsoperatorsoperatorsoperators R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a<-1; b<-2 a=1; b=2; Assignment; defining a number a + b a + b Addition a - b a - b Subtraction a * b a * b Multiplication a / b a / b Division a ^ b a .^ b Power, $a^b$ a %% b rem(a,b) Remainder a %/% b Integer division factorial(a) factorial(a) Factorial, $n!$ RelationalRelationalRelationalRelational operatorsoperatorsoperatorsoperators R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a == b a == b Equal a < b a < b Less than a > b a > b Greater than a <= b a <= b Less than or equal a >= b a >= b Greater than or equal a != b a ~= b Not Equal LogicalLogicalLogicalLogical operatorsoperatorsoperatorsoperators R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a && b a && b Short-circuit logical AND a || b a || b Short-circuit logical OR a & b a & borand(a,b) Element-wise logical AND a | b a | boror(a,b) Element-wise logical OR xor(a, b) xor(a, b) Logical EXCLUSIVE OR !a ~aornot(a) ~a or !a Logical NOT any(a) True if any element is nonzero all(a) True if all elements are nonzero rootrootrootroot andandandand logarithmlogarithmlogarithmlogarithm R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription sqrt(a) sqrt(a) Square root log(a) log(a) Logarithm, base $e$ (natural) log10(a) log10(a) Logarithm, base 10 log2(a) log2(a) Logarithm, base 2 (binary) exp(a) exp(a) Exponential function RoundRoundRoundRound offoffoffoff R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription round(a) round(a) Round ceil(a) ceil(a) Round up floor(a) floor(a) Round down fix(a) Round towards zero MathematicalMathematicalMathematicalMathematical constantsconstantsconstantsconstants R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription pi pi $\pi=3.141592$ exp(1) exp(1) $e=2.718281$ MissingMissingMissingMissing values;values;values;values; IEEE-754IEEE-754IEEE-754IEEE-754 floatingfloatingfloatingfloating pointpointpointpoint statusstatusstatusstatus flagsflagsflagsflags R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription NaN Not a Number Inf Infinity, $\infty$ ComplexComplexComplexComplex numbersnumbersnumbersnumbers R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription 1i i Imaginary unit z <- 3+4i z = 3+4i A complex number, $3+4i$ abs(3+4i)orMod(3+4i) abs(z) Absolute value (modulus) Re(3+4i) real(z) Real part Im(3+4i) imag(z) Imaginary part Arg(3+4i) arg(z) Argument Conj(3+4i) conj(z) Complex conjugate TrigonometryTrigonometryTrigonometryTrigonometry R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription atan2(b,a) atan(a,b) Arctangent, $\arctan(b/a)$ GenerateGenerateGenerateGenerate randomrandomrandomrandom numbersnumbersnumbersnumbers R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription runif(10) rand(1,10) Uniform distribution runif(10, min=2, max=7) 2+5*rand(1,10) Uniform: Numbers between 2 and 7 matrix(runif(36),6) rand(6) Uniform: 6,6 array rnorm(10) randn(1,10) Normal distribution VectorsVectorsVectorsVectors R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a <- c(2,3,4,5) a=[2 3 4 5]; Row vector, $1 \times n$-matrix adash <- t(c(2,3,4,5)) adash=[2 3 4 5]'; Column vector, $m \times 1$-matrix SequencesSequencesSequencesSequences R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription seq(10)or1:10 1:10 1,2,3, ... ,10 seq(0,length=10) 0:9 0.0,1.0,2.0, ... ,9.0 seq(1,10,by=3) 1:3:10 1,4,7,10 seq(10,1)or10:1 10:-1:1 10,9,8, ... ,1 seq(from=10,to=1,by=-3) 10:-3:1 10,7,4,1 seq(1,10,length=7) linspace(1,10,7) Linearly spaced vector of n=7 points rev(a) reverse(a) Reverse a(:) = 3 Set all values to same scalar value ConcatenationConcatenationConcatenationConcatenation (vectors)(vectors)(vectors)(vectors) R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription c(a,a) [a a] Concatenate two vectors c(1:4,a) [1:4 a] RepeatingRepeatingRepeatingRepeating R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription rep(a,times=2) [a a] 1 2 3, 1 2 3 rep(a,each=3) 1 1 1, 2 2 2, 3 3 3 rep(a,a) 1, 2 2, 3 3 3 MissMissMissMiss thosethosethosethose elementselementselementselements outoutoutout R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a[-1] a(2:end) miss the first element a[-10] a([1:9]) miss the tenth element a[-seq(1,50,3)] miss 1,4,7, ... a(end) last element a(end-1:end) last two elements MaximumMaximumMaximumMaximum andandandand minimumminimumminimumminimum R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription pmax(a,b) max(a,b) pairwise max max(a,b) max([a b]) max of all values in two vectors v <- max(a) ; i <- which.max(a) [v,i] = max(a) VectorVectorVectorVector multiplicationmultiplicationmultiplicationmultiplication R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a*a a.*a Multiply two vectors dot(u,v) Vector dot product, $u \cdot v$ MatricesMatricesMatricesMatrices R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription rbind(c(2,3),c(4,5)) a = [2 3;4 5] Define a matrix array(c(2,3,4,5), dim=c(2,2)) ConcatenationConcatenationConcatenationConcatenation (matrices);(matrices);(matrices);(matrices); rbindrbindrbindrbind andandandand cbindcbindcbindcbind R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription rbind(a,b) [a ; b] Bind rows cbind(a,b) [a , b] Bind columns [a(:), b(:)] Concatenate matrices into one vector rbind(1:4,1:4) [1:4 ; 1:4] Bind rows (from vectors) cbind(1:4,1:4) [1:4 ; 1:4]' Bind columns (from vectors) ArrayArrayArrayArray creationcreationcreationcreation R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription matrix(0,3,5)orarray(0,c(3,5)) zeros(3,5) 0 filled array matrix(1,3,5)orarray(1,c(3,5)) ones(3,5) 1 filled array matrix(9,3,5)orarray(9,c(3,5)) ones(3,5)*9 Any number filled array diag(1,3) eye(3) Identity matrix diag(c(4,5,6)) diag([4 5 6]) Diagonal magic(3) Magic squares; Lo Shu ReshapeReshapeReshapeReshape andandandand flattenflattenflattenflatten matricesmatricesmatricesmatrices R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription matrix(1:6,nrow=3,byrow=T) reshape(1:6,3,2)'; Reshaping (rows first) matrix(1:6,nrow=2) array(1:6,c(2,3)) reshape(1:6,2,3); Reshaping (columns first) as.vector(t(a)) a'(:) Flatten to vector (by rows, like comics) as.vector(a) a(:) Flatten to vector (by columns) a[row(a) <= col(a)] vech(a) Flatten upper triangle (by columns) SharedSharedSharedShared datadatadatadata (slicing)(slicing)(slicing)(slicing) R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription b = a b = a Copy of a IndexingIndexingIndexingIndexing andandandand accessingaccessingaccessingaccessing elementselementselementselements (Python:(Python:(Python:(Python: slicing)slicing)slicing)slicing) R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a <- rbind(c(11, 12, 13, 14), c(21, 22, 23, 24), c(31, 32, 33, 34)) a = [ 11 12 13 14 ... 21 22 23 24 ... 31 32 33 34 ] Input is a 3,4 array a[2,3] a(2,3) Element 2,3 (row,col) a[1,] a(1,:) First row a[,1] a(:,1) First column a([1 3],[1 4]); Array as indices a[-1,] a(2:end,:) All, except first row a(end-1:end,:) Last two rows a(1:2:end,:) Strides: Every other row a[-2,-3] All, except row,column (2,3) a[,-2] a(:,[1 3 4]) Remove one column AssignmentAssignmentAssignmentAssignment R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a[,1] <- 99 a(:,1) = 99 a[,1] <- c(99,98,97) a(:,1) = [99 98 97]' a[a>90] <- 90 a(a>90) = 90; Clipping: Replace all elements over 90 TransposeTransposeTransposeTranspose andandandand inverseinverseinverseinverse R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription t(a) a' Transpose a.'ortranspose(a) Non-conjugate transpose det(a) det(a) Determinant solve(a) inv(a) Inverse ginv(a) pinv(a) Pseudo-inverse norm(a) Norms eigen(a)$values eig(a) Eigenvalues svd(a)$d svd(a) Singular values chol(a) Cholesky factorization eigen(a)$vectors [v,l] = eig(a) Eigenvectors rank(a) rank(a) Rank SumSumSumSum R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription apply(a,2,sum) sum(a) Sum of each column apply(a,1,sum) sum(a') Sum of each row sum(a) sum(sum(a)) Sum of all elements apply(a,2,cumsum) cumsum(a) Cumulative sum (columns) SortingSortingSortingSorting R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a = [ 4 3 2 ; 2 8 6 ; 1 4 7 ] Example data t(sort(a)) sort(a(:)) Flat and sorted apply(a,2,sort) sort(a) Sort each column t(apply(a,1,sort)) sort(a')' Sort each row sortrows(a,1) Sort rows (by first row) order(a) Sort, return indices MaximumMaximumMaximumMaximum andandandand minimumminimumminimumminimum R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription apply(a,2,max) max(a) max in each column apply(a,1,max) max(a') max in each row max(a) max(max(a)) max in array i <- apply(a,1,which.max) [v i] = max(a) return indices, i pmax(b,c) max(b,c) pairwise max apply(a,2,cummax) cummax(a) MatrixMatrixMatrixMatrix manipulationmanipulationmanipulationmanipulation R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a[,4:1] fliplr(a) Flip left-right a[3:1,] flipud(a) Flip up-down rot90(a) Rotate 90 degrees kronecker(matrix(1,2,3),a) repmat(a,2,3) kron(ones(2,3),a) Repeat matrix: [ a a a ; a a a ] a[lower.tri(a)] <- 0 triu(a) Triangular, upper a[upper.tri(a)] <- 0 tril(a) Triangular, lower EquivalentsEquivalentsEquivalentsEquivalents totototo "size""size""size""size" R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription dim(a) size(a) Matrix dimensions ncol(a) size(a,2)orlength(a) Number of columns prod(dim(a)) length(a(:)) Number of elements ndims(a) Number of dimensions object.size(a) Number of bytes used in memory Matrix-Matrix-Matrix-Matrix- andandandand elementwise-elementwise-elementwise-elementwise- multiplicationmultiplicationmultiplicationmultiplication R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a * b a .* b Elementwise operations a %*% b a * b Matrix product (dot product) outer(a,b)ora %o% b Outer product crossprod(a,b)ort(a) %*% b Cross product kronecker(a,b) kron(a,b) Kronecker product a / b Matrix division, $b{\cdot}a^{-1}$ solve(a,b) a \ b Left matrix division, $b^{-1}{\cdot}a$ \newline (solve linear equations) Find;Find;Find;Find; conditionalconditionalconditionalconditional indexingindexingindexingindexing R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription which(a != 0) find(a) Non-zero elements, indices which(a != 0, arr.ind=T) [i j] = find(a) Non-zero elements, array indices ij <- which(a != 0, arr.ind=T); v <- a[ij] [i j v] = find(a) Vector of non-zero values which(a>5.5) find(a>5.5) Condition, indices ij <- which(a>5.5, arr.ind=T); v <- Return values a[ij] a .* (a>5.5) Zero out elements above 5.5 Multi-wayMulti-wayMulti-wayMulti-way arraysarraysarraysarrays R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription a = cat(3, [1 2; 1 2],[3 4; 3 4]); Define a 3-way array a(1,:,:) FileFileFileFile inputinputinputinput andandandand outputoutputoutputoutput R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription f <- read.table("data.txt") f = load('data.txt') Reading from a file (2d) f <- read.table("data.txt") f = load('data.txt') Reading from a file (2d) f <- read.table(file="data.csv", sep=";") x = dlmread('data.csv', ';') Reading fram a CSV file (2d) write(f,file="data.txt") save -ascii data.txt f Writing to a file (2d) PlottingPlottingPlottingPlotting BasicBasicBasicBasic x-yx-yx-yx-y plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription plot(a, type="l") plot(a) 1d line plot plot(x[,1],x[,2]) plot(x(:,1),x(:,2),'o') 2d scatter plot plot(x1,y1, x2,y2) Two graphs in one plot plot(x1,y1) matplot(x2,y2,add=T) plot(x1,y1) hold on plot(x2,y2) Overplotting: Add new plots to current subplot(211) subplots plot(x,y,type="b",col="red") plot(x,y,'ro-') Plotting symbols and color AxesAxesAxesAxes andandandand titlestitlestitlestitles R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription grid() grid on Turn on grid lines plot(c(1:10,10:1), asp=1) axis equal axis('equal') replot 1:1 aspect ratio plot(x,y, xlim=c(0,10), ylim=c(0,5)) axis([ 0 10 0 5 ]) Set axes manually plot(1:10, main="title", xlab="x-axis", ylab="y-axis") title('title') xlabel('x-axis') ylabel('y-axis') Axis labels and titles LogLogLogLog plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription plot(x,y, log="y") semilogy(a) logarithmic y-axis plot(x,y, log="x") semilogx(a) logarithmic x-axis plot(x,y, log="xy") loglog(a) logarithmic x and y axes FilledFilledFilledFilled plotsplotsplotsplots andandandand barbarbarbar plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription plot(t,s, type="n", xlab="", ylab="") polygon(t,s, col="lightblue") polygon(t,c, col="lightgreen") fill(t,s,'b', t,c,'g') % fill has a bug? Filled plot stem(x[,3]) Stem-and-Leaf plot FunctionsFunctionsFunctionsFunctions R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription f <- function(x) sin(x/3) - cos(x/5) f = inline('sin(x/3) - cos(x/5)') Defining functions plot(f, xlim=c(0,40), type='p') ezplot(f,[0,40]) fplot('sin(x/3) - cos(x/5)',[0,40]) % no ezplot Plot a function for given range PolarPolarPolarPolar plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription theta = 0:.001:2*pi; r = sin(2*theta); polar(theta, rho) HistogramHistogramHistogramHistogram plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription hist(rnorm(1000)) hist(randn(1000,1)) hist(rnorm(1000), breaks= -4:4) hist(randn(1000,1), -4:4) hist(rnorm(1000), breaks=c(seq(-5,0,0.25), seq(0.5,5,0.5)), freq=F) plot(apply(a,1,sort),type="l") plot(sort(a)) 3d3d3d3d datadatadatadata ContourContourContourContour andandandand imageimageimageimage plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription contour(z) contour(z) Contour plot filled.contour(x,y,z, nlevels=7, color=gray.colors) contourf(z); colormap(gray) Filled contour plot image(z, col=gray.colors(256)) image(z) colormap(gray) Plot image data quiver() Direction field vectors PerspectivePerspectivePerspectivePerspective plotsplotsplotsplots ofofofof surfacessurfacessurfacessurfaces overoveroverover thethethethe x-yx-yx-yx-y planeplaneplaneplane R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/OctaveMATLAB/OctaveMATLAB/Octave DescriptionDescriptionDescriptionDescription f <- function(x,y) x*exp(-x^2-y^2) n <- seq(-2,2, length=40) z <- outer(n,n,f) n=-2:.1:2; [x,y] = meshgrid(n,n); z=x.*exp(-x.^2-y.^2); persp(x,y,z, theta=30, phi=30, expand=0.6, ticktype='detailed') mesh(z) Mesh plot persp(x,y,z, theta=30, phi=30, expand=0.6, col='lightblue', shade=0.75, ltheta=120, ticktype='detailed') surf(x,y,z)orsurfl(x,y,z) % no surfl() Surface plot ScatterScatterScatterScatter (cloud)(cloud)(cloud)(cloud) plotsplotsplotsplots R/S-PlusR/S-PlusR/S-PlusR/S-Plus MATLAB/OctaveMATLAB/O