计算方法上机实验.docx

计算方法上机实验

第一篇：计算方法上机实验龙格-库塔#include#includefloatfunction(floatx,floaty){return(0-(y*y));//f(x,y)µÄ±í´ïʽ}intmain(){floatx0,x1,y0,y1,k1,k2,k3,k4,a,b,c,n,h;inti;scanf(“%f%f%f%f”,&a,&b,&c,&n);x0=a;y0=c;h=(b-a)/n;for(i=1;i{k1=h*function(x0,y0);k2=h*function(x0+h/2,y0+k1/2);k3=h*function(x0+h/2,y0+k2/2);k4=h*function(x0+h,y0+k3);x1=x0+h;y1=y0+(k1+2*k2+2*k3+k4)/6;printf(“x%d=%f,y%d=%fn”,i,x1,i,y1);x0=x1;y0=y1;}return0;}拉格朗日#include#include#include#definemaxlength500#definepi3.14***floata[maxlength],f[maxlength];floatn;floatlagrange(floata[],floatf[],floatx,intn){intk=0,j;floaty=0.0,l;while(k{l=1.0;//printf(“%lfn”,y);for(j=0;j{if(j!=k){l=l*(x-a[j])/(a[k]-a[j]);//printf(“%lfn”,l);}}//printf(“%lfn”,f[k]);//printf(“%lfn”,l);y=y+l*f[k];k++;}printf(“x=%f,y=%fn”,x,y);returny;}floatfx1(floatx){return(1/(1+x*x));}floatfx2(floatx){returnexp(x);}floatfx3(floatx){returnsqrt(x);}voidmath1(floatc,floatn){inti=0;floath;h=2*c/n;while(i{a[i]=i*h-5;i++;}}voidmath2(){inti=0;while(i{a[i]=cos((2*i+1)*pi/2/(n+1));i++;}}intmain(){n=20;inti;math1(5,n);for(i=0;i{f[i]=fx1(a[i])}lagrange(a,f,0.75,n);return0;}龙贝格#include#include#includedoublet[1000],r[1000];doublef(doublex){return(x*x*exp(x));}intmain(){doubleh,a,b,e;inti,N,m;scanf(“%lf,%lf,%d,%lf”,&a,&b,&N,&e);h=b-a;m=0;t[1]=0.5*h*(f(a)+f(b));printf(“%lf”,t[1]);r[0]=t[0];while(1){printf(“n”);for(i=0;it[i]=r[i];m++;h=h/2;r[0]=t[0]/2;for(i=1;ir[0]+=h*f(a+(i-0.5)*h)/2;printf(“%lf”,r[0]);r[1]=(4*r[0]-t[0])/3;printf(“%lf”,r[1]);if(m==1)continue;r[2]=(16*r[1]-t[1])/15;printf(“%lf”,r[2]);if(m==2)continue;r[3]=(64*r[2]-t[2])/63;printf(“%lf”,r[3]);if(m==3)continue;if((fabs(r[3]-t[3])break;}printf(“nthecurrenttimeis:%dn”,m);return0;}牛顿#include#include#includedoublefunction(doublepoint){return(point*point-2*point*exp(-point)+exp(-2*point));}doubled_function(doublepoint){return(2*point+2*point*exp(-point)-2*exp(-point)-2*exp(-2*point));}intmain(){doublebeginner,error1,error2;intmax_times=0;beginner=error1=error2=0;scanf(“%lf%lf%lf%d”,&beginner,&error1,&error2,