机械优化设计黄金分割法 外推法
郑州大学
机械优化设计部分程序
1.外推法
2.黄金分割法
3.二次插值法
4.坐标轮换法
5.随机方向法
6.四杆机构优化设计
1.外推法源程序:
#include
{ double m;
m=x*x-10*x+36;
return m;
}
void main()
{
double h0=R,y1,y2,y3,x1,x2,x3,h;
x1=0;h=h0;x2=h;
y1=fun(x1);y2=fun(x2);
if(y2>y1)
{h=-h;
x3=x1;
y3=y1;
x1=x2;
y1=y2;
x2=x3;
y2=y3;
}
x3=x2+h;y3=fun(x3);
while(y3 {h*=2.0; x1=x2; y1=y2; x2=x3; y2=y3; x3=x2+h; y3=fun(x3); } printf("fun(%f)=%f,fun(%f)=%f,fun(%f)= %f\n",x1,y1,x2,y2,x3,y3); } 运行过程及结果: fun(2.560000)=16.953600, fun(5.120000)=11.014400, fun(10.240000)=38.457600 2.黄金分割法 源程序: #include #include #define f(x) x*x*x*x-5*x*x*x+4*x*x-6*x+60 double hj(double *a,double *b,double e,int *n) { double x1,x2,s; if(fabs((*b-*a)/(*b))<=e) s=f((*b+*a)/2); else { x1=*b-0.618*(*b-*a); x2=*a+0.618*(*b-*a); if(f(x1)>f(x2)) *a=x1; else *b=x2; *n=*n+1; s=hj(a,b,e,n); } return s; } void main() { double s,a,b,e,m; int n=0; printf("输入a,b值和精度e值\n"); scanf("%lf %lf %lf",&a,&b,&e); s=hj(&a,&b,e,&n); m=(a+b)/2; printf("a=%lf,b=%lf,s=%lf,m=%lf,n=%d\n",a,b ,s,m,n); } 运行过程及结果: 输入a,b值和精度e值 -3 5 0.0001 a=3.279466,b=3.279793,s=22.659008,m=3.279 629,n=21 3.二次插值法 源程序: #include #include int main(void) { double a1,a2,a3,ap,y1,y2,y3,yp,c1,c2,m; double j[3]; int i,h=1; void finding(double a[3]); finding(j); a1=j[0]; a2=j[1]; a3=j[2]; m=0.001; double f(double x); y1=f(a1); y2=f(a2); y3=f(a3); for(i=1;1>=1;i++) { c1=(y3-y1)/(a3-a1); c2=((y2-y1)/(a2-a1)-c1)/(a2-a3); ap=0.5*(a1+a3-c1/c2); yp=f(ap); if(fabs((y2-yp)/y2) break; else if((ap-a2)*h>0) { if(y2>=yp){ a1=a2;y1=y2; a2=ap;y2=yp;} else{ a3=ap;y3=yp;} } else if(y2>=yp){ a3=a2;y3=y2; a2=ap;y2=yp;} else{a1=ap;y1=yp;} } double x,y; if(y2<=yp){ x=a2;y=y2;} else{ x=ap;y=yp;} printf("a*=%f\n",x); printf("y*=%f\n",y); return 0; } double f(double x) { double y; y=x*x-10*x+36; return y; } void finding(double a[3]) { int h,i; double y[3]; a[0]=0; h=1; a[1]=h; y[0]=f(a[0]);y[1]=f(a[1]); if(y[1]>y[0]) { h=-h; a[2]=a[0];y[2]=y[0]; do{ a[0]=a[1];a[1]=a[2]; y[0]=y[1];y[1]=y[2]; a[2]=a[1]+h;y[2]=f(a[2]); h=2*h; }while(y[2] } else{ for(i=1;i>=1;i++){ a[2]=a[1]+h;y[2]=f(a[2]); if(y[2]>=y[1]) break; h=2*h; a[0]=a[1];y[0]=y[1]; a[1]=a[2];y[1]=y[2];} } return; } 运行过程及结果: a*=5.000000 y*=11.000000 4.坐标轮换法 源程序: #include #include #include float fun1(float x,float a,float b) {float y; y=x+a*b; return y; } float fun2(float x,float y) {float z; z=4*(x-5)*(x-5)+(y-6)*(y-6); return z; } main() {float d[100][3],x[100][3],xx[3],ax[100][3]; float a1,a2,a3,h,t,y1,y2,y3,e,a,b,l,fi; int i,k; printf("输入初始点坐标\n"); scanf("%f%f",&x[0][1],&x[0][2]); e=0.000001; l=0.618; x[2][1]=x[0][1]; x[2][2]=x[0][2]; k=0; k--; do {x[0][1]=x[2][1]; x[0][2]=x[2][2]; k++; for(i=1;i<=2;i++) { if(i==1) {d[i][1]=1; d[i][2]=0; } else {d[i][1]=0; d[i][2]=1; } h=0.1; a1=0; a2=h; x[i][1]=fun1(x[i-1][1],d[i][1],a1); x[i][2]=fun1(x[i-1][2],d[i][2],a1); y1=fun2(x[i][1],x[i][2]); x[i][1]=fun1(x[i-1][1],d[i][1],a2); x[i][2]=fun1(x[i-1][2],d[i][2],a2); y2=fun2(x[i][1],x[i][2]); if(y2>y1) {h=-h; a3=a1; y3=y1; a1=a2; a2=a3; y1=y2; y2=y3; } a3=a2+h; x[i][1]=fun1(x[i-1][1],d[i][1],a3); x[i][2]=fun1(x[i-1][2],d[i][2],a3); y3=fun2(x[i][1],x[i][2]); do {a1=a2; y1=y2; a2=a3; y2=y3; a3=a2+h; x[i][1]=fun1(x[i-1][1],d[i][1],a3); x[i][2]=fun1(x[i-1][2],d[i][2],a3); y3=fun2(x[i][1],x[i][2]); } while(y3 for(;a1>a3;) {t=a3; a3=a1; a1=t; t=y1; y3=y1; y1=t; } a=a1; b=a3; a1=b-l*(b-a); a2=a+l*(b-a); x[i][1]=fun1(x[i-1][1],d[i][1],a1); x[i][2]=fun1(x[i-1][2],d[i][2],a1); y1=fun2(x[i][1],x[i][2]); x[i][1]=fun1(x[i-1][1],d[i][1],a2); x[i][2]=fun1(x[i-1][2],d[i][2],a2); y2=fun2(x[i][1],x[i][2]); if(b<1e-3) { for(;fabs(b-a)>e;) { if(y1>=y2) {a=a1; a1=a2; y1=y2; a2=a+l*(b-a); x[i][1]=fun1(x[i-1][1],d[i][1],a2); x[i][2]=fun1(x[i-1][2],d[i][2],a2); y2=fun2(x[i][1],x[i][2]); } else {b=a2; a2=a1; y2=y1; a1=b-l*(b-a); x[i][1]=fun1(x[i-1][1],d[i][1],a1); x[i][2]=fun1(x[i-1][2],d[i][2],a1); y1=fun2(x[i][1],x[i][2]); } } } else { for(;fabs((b-a)/b)>=e||fabs((y2-y1)/y2)>=e; ) { if(y1>=y2) {a=a1; a1=a2; y1=y2; a2=a+l*(b-a); x[i][1]=fun1(x[i-1][1],d[i][1],a2); x[i][2]=fun1(x[i-1][2],d[i][2],a2); y2=fun2(x[i][1],x[i][2]); } else {b=a2; a2=a1; y2=y1; a1=b-l*(b-a); x[i][1]=fun1(x[i-1][1],d[i][1],a1); x[i][2]=fun1(x[i-1][2],d[i][2],a1); y1=fun2(x[i][1],x[i][2]); } } } ax[k][i]=0.5*(a+b); x[i][1]=fun1(x[i-1][1],d[i][1],ax[k][i]); x[i][2]=fun1(x[i-1][2],d[i][2],ax[k][i]); } } while(sqrt(pow((x[2][1]-x[0][1]),2)+pow((x[2][ 2]-x[0][2]),2))>=1e-6); xx[1]=x[2][1]; xx[2]=x[2][2]; fi=fun2(xx[1],xx[2]); printf("最优解为\nx1*=%f\nx2*=%f\n f*=%f\nk=%d\n",xx[1],xx[2],fi,k); } 运行过程及结果: 输入初始点坐标 8 9 最优解为 x1*=5.000000 x2*=6.000000 f*=0.000000 k=2 5.随机方向法 源程序: #include #include #include float f(float x,float y) { float z; z=(x-2)*(x-2)+(y-1)*(y-1); return z; } float g1(float x,float y) { float z; z=x*x-y; return z; } float g2(float x,float y) { float z; z=x+y-2; return z; } void main() { int i,j; float k=8,c=0.000001,a0=-3,b0=3,a1=-3,b1=3; float x[10],x0[10],xl[10],e[10],r[10],d[10],h,fl,f0,fx; while(g1(x0[0],x0[1])>0||g2(x0[0],x0[1])>0) { x0[0]=a0+(rand()/32767.00)*(b0-a0); x0[1]=a1+(rand()/32767.00)*(b1-a1); } fl=f(x0[0],x0[1]); f0=f(x0[0],x0[1]); while(1) { h=0.01; j=1; r[0]=-1+(rand()/32767.00)*(1-(-1)); r[1]=-1+(rand()/32767.00)*(1-(-1)); e[0]=r[0]/sqrt(r[0]*r[0]+r[1]*r[1]); e[1]=r[1]/sqrt(r[0]*r[0]+r[1]*r[1]); x[0]=x0[0]+h*e[0]; x[1]=x0[1]+h*e[1]; if(g1(x[0],x[1])<=0&&g2(x[0],x[1])<=0) { fx=f(x[0],x[1]); if(fx { fl=fx; for(i=0;i<2;i++) {d[i]=e[i];xl[i]=x[i];} } } while(j<=k) { j++; r[0]=-1+(rand()/32767.00)*(1-(-1)); r[1]=-1+(rand()/32767.00)*(1-(-1)); e[0]=r[0]/sqrt(r[0]*r[0]+r[1]*r[1]); e[1]=r[1]/sqrt(r[0]*r[0]+r[1]*r[1]); x[0]=x0[0]+h*e[0]; x[1]=x0[1]+h*e[1]; if(g1(x[0],x[1])<=0&&g2(x[0],x[1])<=0) { fx=f(x[0],x[1]); if(fx { fl=fx; for(i=0;i<2;i++) {d[i]=e[i];xl[i]=x[i];} } } } x[0]=xl[0]; x[1]=xl[1]; while(1) { h=1.3*h; x[0]=x[0]+h*d[0]; x[1]=x[1]+h*d[1]; if(g1(x[0],x[1])>0||g2(x[0],x[1])>0) break; fx=f(x[0],x[1]); if(fx else break; } do { x[0]=x[0]-h*d[0]; x[1]=x[1]-h*d[1]; h=0.7*h; if(h break; x[0]=x[0]+h*d[0]; x[1]=x[1]+h*d[1]; if(g1(x[0],x[1])>0||g2(x[0],x[1])>0) continue; fx=f(x[0],x[1]); } while(fx>=fl); if(fabs((f0-fx)/f0)>=c)