测控软件技术基础周鑫资料Word文件下载.docx
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测控软件技术基础周鑫资料Word文件下载.docx
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6.Createavectorxwiththeelements,
xn=(-1)n+1/(2n-1)
Adduptheelementsoftheversionofthisvectorthathas100elements.
n=1:
100;
x=((-1).^(n+1))./(2*n-1);
y=sum(x)
10.Makeagoodplot(i.e.,anon-choppyplot)ofthefunction
f(x)=sin(1/x)
for0.01<
x<
0.1.Howdidyoucreatexsothattheplotlooked
good?
x=0.01:
0.0001:
0.1;
y=sin(1./x);
plot(x,y)
BasicArraySyntaxandManipulations
1.Givenx=[3157926],explainwhatthefollowingcommands"
mean"
by
bysummarizingthenetresultofthecommand.
a.x(3)
b.x(1:
7)
c.x(1:
end)
d.x(1:
end-1)
e.x(6:
1)
f.x([16211])
g.sum(x)
答:
x(3)表示x行向量中的第三个元素。
x(1:
7)表示x行向量中第1到7个元素。
end)表示x行向量中第1到最后一个元素。
end-1)表示x行向量中第1到倒数第二个元素。
x(6:
1)表示x行向量中第6个元素到第1个元素中的偶数项元素。
x([16211]):
方括号中表示x行向量中元素的序号,整个表示由这些元素组成的新行向量。
sum(x):
表示x中所有元素求和。
2.GiventhearrayA=[241;
672;
359],providethecommandsneededto
a.assignthefirstrowofAtoavectorcalledx1
b.assignthelast2rowsofAtoanarraycalledy
c.computethesumoverthecolumnsofA
d.computethesumovertherowsofA
e.computethestandarderrorofthemeanofeachcolumnofA(NB.thestandard
errorofthemeanisdefinedasthestandarddeviationdividedbythe
squarerootofthenumberofelementsusedtocomputethemean.)
A=[241;
359]
x1=A(1,:
)
y=A(end-1:
end,:
c=sum(A)
d=sum(A,2)
N=size(A,1),e=std(A)/sqrt(N)
6.GivethefollowingcommandstocreateanarraycalledF:
>
>
randn('
seed'
123456789)
F=randn(5,10);
a.Computethemeanofeachcolumnandassigntheresultstotheelementsofa
vectorcalledavg.
b.Computethestandarddeviationofeachcolumnandassigntheresultstothe
elementsofavectorcalleds.
c.Computethevectoroft-scoresthattestthehypothesisthatthemeanofeach
columnisnodifferentfromzero.
d.IfPr(|t|>
2.132)=0.1with4degreesoffreedom,areanyofthemeanvalues
inthevectoravgstatisticallydifferentfrom0?
randn('
N=size(F,1)
avg=mean(F)
s=std(F)
tscore=(avg-0)./(s/sqrt(N))
ExercisesonRelationalandLogicalOperations
2.Theexerciseshereshowthetechniquesoflogical-indexing(indexingwith
0-1vectors).Givenx=1:
10andy=[3156829470],executeand
interprettheresultsofthefollowingcommands:
a.(x>
3)&
(x<
8)
b.x(x>
5)
c.y(x<
=4)
d.x((x<
2)|(x>
=8))
e.y((x<
f.x(y<
0)
输入代码:
x=1:
10;
y=[3156829470];
运行结果:
a:
ans=
0001111000
b:
678910
c:
3156
d:
18910
e:
3470
f:
Emptymatrix:
1-by-0
4.Givenx=[315912-10-12961],providethecommand(s)thatwill
a....setthevaluesofxthatarepositivetozero
b....setvaluesthataremultiplesof3to3(remwillhelphere)
c....multiplythevaluesofxthatareevenby5
d....extractthevaluesofxthataregreaterthan10intoavectorcalledy
e....setthevaluesinxthatarelessthanthemeantozero
f....setthevaluesinxthatareabovethemeantotheirdifferencefromthemean
x=[315912-10-12961]
a=x,idxa=x>
0,a(idxa)=0
b=x,idxb=~rem(x,3),b(idxb)=3
c=x,idxc=~rem(x,2),c(idxc)=5*c(idxc)
5.Createthevectorx=randperm(35)andthenevaluatethefollowingfunctionusing
onlylogicalindexing:
y(x)=2ifx<
6
=x-4if6<
=x<
20
=36-xif20<
=35
Youcancheckyouranswerbyplottingyvs.xwithsymbols.Thecurveshouldbe
atriangularshape,alwaysabovezeroandwithamaximumof16.Itmightalsobe
usefultotrysettingxto1:
35.Usingmultiplesteps(orasimpleMfile)is
recommendedforthisproblem.
x=1:
35;
y=zeros(size(x));
idx1=x<
6;
idx2=(x>
=6)&
20);
idx3=(x>
=20)&
=35);
y(idx1)=2;
y(idx2)=x(idx2)-4;
y(idx3)=36-x(idx3);
disp([x(:
)idx1(:
)idx2(:
)idx3(:
)y(:
)])
plot(x,y,'
o'
ControlofFlow:
if-blocks
1.ifn>
1a.n=7m=?
m=n+1b.n=0m=?
elsec.n=-10m=?
m=n-1
end
结果:
m=8;
b:
m=-1;
c:
m=-11
2.ifz<
5a.z=1w=?
w=2*zb.z=9w=?
elseifz<
10c.z=60w=?
w=9-zd.z=200w=?
100
w=sqrt(z)
else
w=z
a:
w=2;
w=0;
w=7.7460;
w=200
3.ifT<
30a.T=50h=?
h=2*T+1b.T=15h=?
elseifT<
10c.T=0h=?
h=T-2
h=0
h=0;
b:
h=31;
c:
h=1;
5.h(T)=T-10when0<
T<
=0.45T+900whenT>
100
Testcases:
a.T=5,h=-5
b.T=110,h=949.5
if(T>
0&
&
T<
100)
h(T)=T-10
elseif(T>
h(T)=0.45*T+900
end
ans=
-5
949.5000
6.f(x)=-1ifx<
0
=0ifx=0
=1ifx>
CompareyourresultstotheMATLABfunctionsign.
定义函数:
functiony=ckyjjs(x)
[m,n]=size(x);
y=zeros(size(x));
fora=1:
m
forb=1:
n
if(x(a,b)>
0)
y(a,b)=1;
elseif(x(a,b)==0)
y(a,b)=0;
elseif(x(a,b)<
y(a,b)=-1;
LoopConstructs
1.Giventhevectorx=[183901],createashortsetofcommandsthatwill
a.Addupthevaluesoftheelements(Checkwithsum.)
b.Computestherunningsum(forelementj,therunningsumisthesumofthe
elementsfrom1toj,inclusive.Checkwithcumsum.)
c.computesthesineofthegivenx-values(shouldbeavector)
1.x=[183901]
a:
total=0;
forj=1:
length(x)
total=total+x(j);
b:
runningTotal=zeros(size(x));
runningTotal
(1)=x
(1);
forj=2:
runningTotal(j)=runningTotal(j-1)+x(j);
c:
s=zeros(size(x));
s(j)=sin(x(j));
2.CreateanM-by-Narrayofrandomnumbers(userand).Movethroughthe
array,elementbyelement,andsetanyvaluethatislessthan0.2to0andany
valuethatisgreaterthan(orequalto)0.2to1.
A=rand(4,7);
[M,N]=size(A);
M
fork=1:
N
ifA(j,k)<
0.2
A(j,k)=0;
A(j,k)=1;
3.Givenx=[416]andy=[627],computethefollowingarrays
a.aij=xiyj
b.bij=xi/yj
c.ci=xiyi,thenadduptheelementsofc.
d.dij=xi/(2+xi+yj)
e.eij=reciprocalofthelesserofxiandyj
x=[416],y=[627]
N=length(x);
c(j)=x(j)*y(j);
a(j,k)=x(j)*y(k);
b(j,k)=x(j)/y(k);
d(j,k)=x(j)/(2+x(j)+y(k));
e(j,k)=1/min(x(j),y(k));
c=sum(c)
ProgrammingExercises
2.TheFibonaccinumbersarecomutedaccordingtothefollowingrelation:
Fn=Fn-1+Fn-2
withF0=F1=1.
a.Computethefirst10Fibonaccinumbers.
b.Forthefirst50Fibonaccinumbers,computetheratio
Fn/Fn-1
Itisclaimedthatthisratioapproachesthevalueofthegoldenmean
((1+sqrt(5))/2).Whatdoyourresultsshow?
F
(1)=1;
F
(2)=1;
fora=3:
10
F(a)=F(a-1)+F(a-2);
F
50
F(50)/F(49)
1.6180
3.TheLegendrepolynomials(Pn(x))aredefinedbythefollowingrecurrancerelation
(n+1)Pn+1(x)-(2n+1)xPn(x)+nPn-1(x)=0
withP0(x)=1,P1(x)=xandP2(x)=(3x2-1)/2.Computethenextthree
Legendrepolynomialsandplotall6overtheinterval[-1,1].
FormoreinformationonLegendrepolynomials,seetheMathworldsite.
x=-1:
0.1:
1;
[a,b]=size(x)
fori=1:
b
P0(i)=1;
P1(i)=x(i);
P2(i)=(3*x(i).^2-1)/2;
P3(i)=(5*x(i).*P2(i)-2.*P1(i))/3;
P4(i)=(7*x(i).*P3(i)-3.*P2(i))/4;
P5(i)=(9*x(i).*P4(i)-4.*P3(i))/5;
plot(x,P0,x,P1,x,P2,x,P3,x,P4,x,P5)
12.FollowthedirectionsforExercise11butcreateafunctionthatcomputesthe
cumulativesumoftheelementsofavector.Theelementsofthecumulativesum
vectoraredefinedby
sj=x1+x2+...+xj
lengthofthevectorx.
Thebuilt-infunctionssumandcumsumshouldbeusedinsteadofprodandcumprod,respectively.
functiony=cumulative_sum(x)
y=0;
a=length(x);
s
(1)=x
(1);
fori=2:
a
s(i)=s(i-1)+x(i);
forj=1:
y=y+s(j);
举例:
x=[111111];
cumulative_sum(x)
21
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