机械振动加州大学University of CaliforniaChapter5TwoDimensionalPlotsWord格式文档下载.docx

机械振动加州大学University of CaliforniaChapter5TwoDimensionalPlotsWord格式文档下载.docx

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Specifier

Solid（default）

-

Dotted

:

Dashed

--

Dash-dot

-.

∙Thelinecolorspecifiersare:

LineColor

Red

r

Magenta

m

Green

g

Yellow

y

Blue

b

Black

k

Cyan

c

White

w

∙Themarkertypespecifiersare:

MarkerType

plussign

+

square

s

circle

o

diamond

d

asterisk

*

five-pointedstar

p

point

.

six-pointedstar

h

Notesaboutusingthespecifiers

∙Thespecifiersaretypedinsidetheplotcommandasstrings.

∙Withinthestringthespecifierscanbetypedinanyorder.

∙Thespecifiersareoptional.Thismeansthatnone,one,two,orallthethreecanbeincludedinacommand.

∙Someexamples:

plot（x,y,’r’）Aredsolidlineconnectsthepoints.

plot（x,y,’--y’）Ayellowdashedlineconnectsthepoints.

plot（x,y,’*’）Thepointsaremarkedwith*（nolinebetweenthepoints）.

plot（x,y,’g:

d’）Agreendottedlineconnectsthepointsthataremarkedwithdiamondmarkers.

PropertyNameandPropertyValue:

∙Propertiesareoptionalandcanbeusedtospecifythethicknessoftheline,thesizeofthemarker,andthecolorsofthemarker’sedgelineandfill.

∙ThePropertyNameistypedasastring,followedbyacommandavaluefortheproperty,allinsidetheplotcommand.

∙Fourpropertiesandpossiblevaluesare:

PropertyName

Description

PossiblePropertyValues

LineWidth

（orlinewidth）

Specifiesthewidthoftheline

Anumberinunitsofpoints（default0.5）

MarkerSize

（ormarkersize）

Specifiesthesizeofthemarker

Anumberinunitsofpoints

MarkerEdgeColor

（ormarkeredgecolor）

Specifiesthecolorofthemarker,orthecoloroftheedgelineforfilledmarker.

Colorspecifiers,typedasastring

MarkerFaceColor

（ormarkerfacecolor）

Specifiesthecolorofthefillingforfilledmarker

-Forexample,thecommandscreateaplotthatconnectsthepointswithamagentasolidlineandcirclesasmarkersatthepoints.Thelinewidthistwopointsandthesizeofthecirclemarkersis12points.Themarkershaveagreenedgelineandyellowfilling.

y=[26.5775.5468];

plot（x,y,'

-mo'

'

linewidth'

2,'

markersize'

12,'

markeredgecolor'

g'

markerfacecolor'

y'

）

5.1.1PlotofGivenData

∙Forexample,withthesalesdataofacompanyfrom1988to1994,

yr=[1988:

1:

1994];

sle=[8122022182427];

plot（yr,sle,'

--r*'

12）

5.1.2PlotofaFunction

∙Toplotagivenfunction,usetheplotorthefplotcommands.

∙Withtheplotcommand,theuserneedstofirstcreateavectorofvaluesofxforthedomainthatthefunctionwillbeplotted.Then,avectoryiscreatedbyusingelement-by-elementcalculations.

∙Toplot

for-2x4,

%Chapter5Plot1.m

%thefunction:

3.5.^（-0.5*x）.*cos（6x）

x=[-2:

0.01:

4];

y=3.5.^（-0.5*x）.*cos（6*x）;

helpChapter5Plot1

Chapter5Plot1.m

thefunction:

Chapter5Plot1

-TheplotcanbecopiedfromtheFigureWindow（intheEditmenuselectCopyFigure）andthenpasteitinotherapplications.

5.2THEfplotCOMMAND

∙Thefplotcommandplotsafunctionwiththeformy=f（x）betweenspecifiedlimits.Thecommandhastheform:

fplot（‘function’,limits,linespecifiers）

‘function’

-Thefunctioncanbetypeddirectlyastringinsidethecommand.Forexample,ifthefunctionis

itistypedas‘8*x^2+5*cos（x）’.

-Thefunctioncannotincludepreviouslydefinedvariables.

limits

-Thelimitsisavectorwithtwoelementsthatspecifythedomainofx[xmin,xmax],oravectorwithfourelementsthatspecifiesthedomainofxandthelimitsofthey-axis[xmin,xmax,ymin,ymax].

∙Forexample,aplotof

for

canbecreatedwiththefplotcommand:

fplot（'

x^2+4*sin（2*x）-1'

[-33]）

5.3PLOTTINGMULTIPLEGRAPHSINTHESAMEPLOT

5.3.1UsingtheplotCommand

∙Twoormoregraphscanbecreatedinthesameplotbytypingpairsofvectorsinsidetheplotcommand:

plot（x,y,u,v,t,h）

-Itcreatesthreegraphsallinthesameplot.

-Thevectorsofeachpairmustbeofthesamelength.

-MATLABautomaticallyplotsthegraphsindifferentcolors.

-Itispossibletoaddlinespecifiersfollowingeachpair.Forexample,

plot（x,y,’-b’,u,v,’—r’,t,h,’g:

’）

[SampleProblem5-1]Plotthefunction

anditsfirstandsecondderivatives,for-2x4,allinthesameplot.

%SP5_1.m

y=3*x.^3-26*x+10;

dy=9*x.^2-26;

ddy=18*x;

plot（x,y,'

-b'

x,dy,'

--r'

x,ddy,'

k'

5.3.2Usingtheholdon,holdoffCommands

%SP5_1_a.mforSampleProblem5-1

holdon

plot（x,dy,'

plot（x,ddy,'

5.3.3UsingthelineCommand

∙Withthelinecommandadditionalgraphs（lines）canbeaddedtoaplotthatalreadyexists.Theformofthelinecommandis:

line（x,y,’PropertyName’,propertyValue）

-（Optional）’PropertyName’,propertyValue

-Theformatoflinecommandisalmostthesameastheplotcommand.

-Thelinecommanddoesnothavethelinespecifiers.

∙

Theplotcommandstartsanewploteverytimeitisexecuted,whilethelinecommandaddslinestoaplotthatalreadyexists.Thus,fortheSampleProblem5-1,thefollowingM-filecanbeused:

%SP5_1_b.mforSampleProblem5-1

line（x,dy,'

linestyle'

--'

color'

r'

line（x,ddy,'

'

5.4FORMATTINGAPLOT

∙Afigurethatcontainsaplotneedstobeformattedtodisplayinformationinadditiontothegraphitself.Itcanincludespecifyingaxislabels,plottitle,legend,grid,rangeofcustomaxis,andtextlabels.

5.4.1FormattingaplotUsingCommands

Thexlabelandylabelcommands:

∙Labelscanbeplacednexttotheaxeswiththefollowingcommands:

xlabel（‘textasstring’）

ylabel（‘textasstring’）

Thetitlecommand:

∙Thetextisplacedatthetopofthefigureasatitlewiththefollowingcommand:

title（‘textasstring’）

Thetextcommand:

∙Atextcanbeplacedintheplotwiththetextorgtextcommands:

text（x,y,’textasstring’）

gtext（‘textasstring’）

-Thetextcommandplacesthetextinthefiguresuchthatthefirstcharacterispositionedatthepointwiththecoordinatesx,y（accordingtotheaxesofthefigure）.

-Thegtextcommandplacesthetextatapositionspecifiedbytheuser.Whenthecommandisexecuted,theFigureWindowopensandtheuserspecifiesthepositionwiththemouse.

Thelegendcommand:

∙Toplacealegendontheplot,

legend（‘string1’,‘string2’,…,pos）

-Thestringsarethelabelsthatareplacednexttothelinesample.

-Theirordercorrespondstotheorderthatthegraphswerecreated.

-Theposisanoptionalnumberthatspecifieswhereinthefigurethelegendisplaced.Theoptionsare:

pos=-1Placesthelegendoutsidetheaxesboundariesontherightside.

pos=0Placesthelegendinsidetheaxesboundariesinalocationthatinterferestheleastwiththegraphs.

pos=1Placesthelegendattheupper-rightcorneroftheplot（default）.

pos=2Placesthelegendattheupper-leftcorneroftheplot.

pos=3Placesthelegendatthelower-leftcorneroftheplot.

pos=4Placesthelegendatthelower-rightcorneroftheplot.

Formattingthetext:

∙AcompleteexplanationofalltheformattingfeaturescanbefoundintheHelpWindowunderTextandTextProperties.

∙Theformattingcanbedoneeitherbyaddingmodifiersinsidethestring,orbyaddingtothecommandoptionalPropertyNameandPropertyValueargumentsfollowingthestring.

∙Themodifiersarecharactersthatareinsertedwithinthestring.

Modifier

Effect

\bf

boldfont

\it

italicstyle

\rm

normalfont

\fontname{fontname}

specifiesfontisused

\fontsize{fontsize}

specifiesfontsizeisused

-Thesemodifiersaffectthetextfromthepointthattheyareinserteduntiltheendofthestring.

-Itispossibletohavethemodifiersappliedtoonlyasectionofthestringbytypingthemodifierandthetexttobeaffectedinsidebraces{}.

∙Thesubscriptandsuperscript:

-Asinglecharactercanbedisplayedasasubscriptorasuperscriptbytyping_or^infrontofthecharacter,respectively.

-Severalconsecutivecharacterscanbedisplayedassubscriptorasuperscriptbytypingthecharactersinsidebraces{}followingthe_orthe^.

∙