function-get-the-minimum-.rar_一维搜索_优化设计作业_搜索最小值_最小值

function [ ] = main1_func( ) %UNTITLED2 Summary of this function goes here % Detailed explanation goes here global longth;% 步长 longth=input('请输入步长'); global begginning;%初点 begginning=input('请输入初始点'); global precision;%精度 precision=input('请输入精度'); global way; global qujian1; global qujian2;%计算区间 sub_rearchfield; disp('请从数字1——6中选择输入一个数字作为取极小值小值方法'); disp('1-黄金分割法'); disp('2-平分法'); disp('3-成功失败法'); disp('4-牛顿法'); disp('5-三点二次插值'); disp('6-三次插值法'); way=input('请输入方法所对应的数字'); tic; if way==1 disp('黄金分割法结果如下'); sub_huangjin; end if way==2 disp('平分法结果如下'); sub_pingfen; end if way==3 disp('成功失败法法结果如下'); sub_sandf; end if way ==4 disp('牛顿法结果如下'); sub_niudun; end if way==5 disp('三点二次插值法结果如下'); sub_sandianerci; end if way==6 disp('三次插值法结果如下'); sub_sancichazhi; end toc; end function y = sub_equation(a) %UNTITLED4 Summary of this function goes here % Detailed explanation goes here syms x; equ(x)=x*x+4*x-7; y=equ(a); y=double(y); end function y=sub_equation1(a) syms x; equ(x)=x*x+4*x-7; equ1(x)=diff(equ(x)); y=equ1(a); y=double(y); end function y=sub_equation2(a) syms x; equ(x)=x*x+4*x-7; equ1(x)=diff(equ(x)); equ2(x)=diff(equ1(x)); y=equ2(a); y=double(y); end function [ ] = sub_rearchfield( ) global longth;% 步长 global begginning;%初点 global qujian1; global qujian2;%计算区间 global lastlongth; x1=begginning; x2=x1+longth; y1=sub_equation(x1); y2=sub_equation(x2); if y1>y2 x3=x2+longth; y3=sub_equation(x3); if y2<y3 qujian1=x1; qujian2=x3; end while y2>y3 longth=2*longth; x1=x2;x2=x3; x3=x2+longth; y3=sub_equation(x3); y2=sub_equation(x2); end qujian1=x1; qujian2=x3; end if y1<=y2 longth=-longth; t=x1;w=y1; x1=x2;y1=y2; x2=t;y2=w; x3=x2+longth; y3=sub_equation(x3); while y2>y3 longth=2*longth; x1=x2;x2=x3; x3=x2+longth; y3=sub_equation(x3); y2=sub_equation(x2); end if y2<y3 qujian1=x1; qujian2=x3; end end lastlongth=longth; end function [ ] = sub_huangjin( ) global longth;% 步长 global begginning;%初点 global precision;%精度 global qujian1; global qujian2;%计算区间 global x; global y; number=0;%迭代次数 if qujian1>qujian2 a=qujian2; b=qujian1; end if qujian1<qujian2 a=qujian1; b=qujian2; end x1 = b - 0.618*(b - a); x2 = a + 0.618*(b - a); f1=sub_equation(x1); f2=sub_equation(x2); c=abs(a-b); while c>precision; number=number+1; if f1<=f2 b = x2; x2 = x1; f2 = f1; x1 = b - 0.618*(b - a); f1=sub_equation(x1); end if f1>f2 a = x1; x1 = x2; f1 = f2; x2 = a + 0.618*(b - a); f2= sub_equation(x2); end c = abs(a - b); end jieguo = (a+b) / 2; shuzi = sub_equation(jieguo); disp('程序取极小值点为'); disp(jieguo); disp('程序在极小值点取到极小值为'); disp(shuzi); disp('程序迭代次数为'); disp(number); disp('程序运行时间为'); end%黄金分割法 function [ ]=sub_pingfen( )%平分法 global longth;% 步长 global begginning;%初点 global precision;%精度 global qujian1; global qujian2;%计算区间 global x; global y; global y1; number=0;%迭代次数 if qujian1>qujian2 a=qujian2; b=qujian1; end if qujian1<qujian2 a=qujian1; b=qujian2; end c=abs(a-b); while c>precision; d=(a+b)/2; e=sub_equation1(d); disp(a); disp(b); disp(e); if e>0 number=number+1; b=d; c=abs(a-b); end if e<=0 a=d; c=abs(a-b); number=number+1; end end jieguo = (a+b) / 2; shuzi = sub_equation(jieguo); disp('程序取极小值点为'); disp(jieguo); disp('程序在极小值点取到极小值为'); disp(shuzi); disp('程序迭代次数为'); disp(number); disp('程序运行时间为'); end function [ ]=sub_sandf()%成功失败法 global longth;% 步长 global begginning;%初点 global precision;%精度 global qujian1; global qujian2;%计算区间 global x; global y; global y1; number=0;%迭代次数 if qujian1>qujian2 a=qujian2; b=qujian1; end if qujian1<qujian2 a=qujian1; b=qujian2; end x0=begginning; fail=0; wocao=0; while wocao==0 x1=x0+longth; number=number+1; f0=sub_equation(x0); f1=sub_equation(x1); if f1<f0 if fail==0 longth=2*longth; x0=x1; end if fail==1 longth=longth; x0=x1; end end if f1>f0 fail=1; if abs(longth)<precision wocao=1; jieguo=x0; end if abs(longth)>=precision longth=-0.25*longth; x0=x1; end end if f1==f0 wocao=1; jieguo=(x0+x1)/2; end end shuzi = sub_equation(jieguo); disp('程序取极小值点为'); disp(jieguo); disp('程序在极小值点取到极小值为'); disp(shuzi); disp('程序迭代次数为'); disp(number); disp('程序运行时间为'); end function [ ]=sub_niudun()%牛顿法 global longth;% 步长 global begginning;%初点 global precision;%精度 global qujian1; global qujian2;%计算区间 global x; global y; number=0;%迭代次数 if qujian1>qujian2 a=qujian2; b=qujian1; end if qujian1<qujian2 a=qujian1; b=qujian2; end wocao=0; a1=b; while wocao==0 a2=a1-sub_equation1(a1)/sub_equation2(a1); w=abs(a2-a1); number=number+1; if w<=precision wocao=1; jieguo=a2; end if w>precision a1=a2; end end shuzi = sub_equation(jieguo); disp('程序取极小值点为'); disp(jieguo); disp('程序在极小值点取到极小值为'); disp(shuzi); disp('程序迭代次数为'); disp(number); disp('程序运行时间为'); end function [ ]=sub_sandianerci()%三点二次插值 global longth;% 步长 global begginning;%初点 global precision;%精度 global qujian1; global qujian2;%计算区间 global x; global y; global lastlongth; number=0;%迭代次数 if qujian1>qujian2 a=qujian2; b=qujian1; end if qujian1<qujian2 a=qujian1; b=qujian2; end a1=a; a3=b; a2=(a1+a3)/2; %if sub_equation(a1)>=sub_equation(a3) % a2=a3-0.1; %end %if sub_equation(a1)<sub_equation(a3) % a2=a1+0.1; %end y1=sub_equation(a1); y2=sub_equation(a2); y3=sub_equation(a3); c1=(y3-y1)/(a3-a1); c2=[(y2-y1)/(a2-a1)-c1]/(a2-a3); ap=0.5*(a1+a3-c1/c2); yp=sub_equation(ap); wocao=abs((y2-yp)/y2); disp(wocao); while wocao>=precision number=number+1; wo=(ap-a2)*lastlongth; if wo>0 if y2>=yp a1=a2; y1=y2; a2=ap; y2=yp; end if y2<yp a3=ap; y3=yp; end end if wo<=0 if y2>=yp a3=a2; y3=y2; a2=ap; y2=yp; end if y2<yp a1=ap; y1=yp; end end c1=(y3-y1)/(a3-a1); c2=[(y2-y1)/(a2-a1)-c1]/(a2-a3); ap=0.5*(a1+a3-c1/c2); yp=sub_equation(ap); wocao=abs((y2-yp)/y2); end if y2<yp jieguo=a2; shuzi=y2; end if y2>=yp jieguo=ap; shuzi=yp; end disp('程序取极小值点为'); disp(jieguo); disp('程序在极小值点取到极小值为'); disp(shuzi); disp('程序迭代次数为'); disp(number); disp('程序运行时间为'); end function [ ]=sub_sancichazhi()%三次插值法 global longth;% 步长 global begginning;%初点 global precision;%精度 global qujian1; global qujian2;%计算区间 global x; global y; number=0;%迭代次数 if qujian1>qujian2 a=qujian2; b=qujian1; end if qujian1<qujian2 a=qujian1; b=qujian2; end u=sub_equation1(b); v=sub_equation1(a); fa=sub_equation(a); fb=sub_e