📄 ch7.h
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for (j=0; j<=n-1; j++)
{ qq=c[j]-9.0*(b[j]-2.0*a[j]/9.0)/8.0;
qq=d[j]-8.0*qq;
y[j]=y[j]+hh*qq/6.0;
}
t=t+dt;
}
p=0.0;
for (j=0; j<=n-1; j++)
{ qq=fabs(y[j]-v[j]);
if (qq>p) p=qq;
}
hh=hh/2.0; nn=nn+nn;
}
for (j=0; j<=n-1; j++) z[j*k+i]=y[j];
}
free(a); free(b); free(c); free(d); free(u); free(v);
return;
}
/////////////////////////////////////////////////////////////
static void rkt1(double t,double h,int n,double y[],double b[],double d[],double e[],
void (*gpbs1f)(double t,double y[],int n,double d[]))
{
//extern void gpbs1f();
int i,k;
double a[4],tt;
a[0]=h/2.0; a[1]=a[0]; a[2]=h; a[3]=h;
gpbs1f(t,y,n,d);
for (i=0; i<=n-1; i++) { b[i]=y[i]; e[i]=y[i];}
for (k=0; k<=2; k++)
{ for (i=0; i<=n-1; i++)
{ y[i]=e[i]+a[k]*d[i];
b[i]=b[i]+a[k+1]*d[i]/3.0;
}
tt=t+a[k];
gpbs1f(tt,y,n,d);
}
for (i=0; i<=n-1; i++)
y[i]=b[i]+h*d[i]/6.0;
return;
}
void gpbs1(double t,double h,int n,double y[],double eps,
void (*gpbs1f)(double t,double y[],int n,double d[]))
{
int i,j,k,m,nn,it;
//void rkt1();
double x,hh,dd,q,p,g[10],*b,*d,*u,*v,*w,*e;
b=(double*)malloc(10*n*sizeof(double));
d=(double*)malloc(n*sizeof(double));
u=(double*)malloc(n*sizeof(double));
v=(double*)malloc(n*sizeof(double));
w=(double*)malloc(n*sizeof(double));
e=(double*)malloc(n*sizeof(double));
for (j=0; j<=n-1; j++) v[j]=y[j];
x=t; nn=1; hh=h; g[0]=hh;
rkt1(x,hh,n,y,w,d,e,gpbs1f);
for (j=0; j<=n-1; j++)
{ b[j]=y[j]; u[j]=y[j];}
k=1; it=1;
while (it==1)
{ nn=nn+nn; hh=hh/2.0; it=0;
g[k]=hh;
for (j=0; j<=n-1; j++) y[j]=v[j];
t=x;
for (j=0; j<=nn-1; j++)
{ rkt1(t,hh,n,y,w,d,e,gpbs1f);
t=t+hh;
}
for (j=0; j<=n-1; j++)
{ dd=y[j]; m=0;
for (i=0; i<=k-1; i++)
if (m==0)
{ q=dd-b[i*n+j];
if (fabs(q)+1.0==1.0) m=1;
else dd=(g[k]-g[i])/q;
}
b[k*n+j]=dd;
if (m!=0) b[k*n+j]=1.0e+35;
}
for (j=0; j<=n-1; j++)
{ dd=0.0;
for (i=k-1; i>=0; i--)
dd=-g[i]/(b[(i+1)*n+j]+dd);
y[j]=dd+b[j];
}
p=0.0;
for (j=0; j<=n-1; j++)
{ q=fabs(y[j]-u[j]);
if (q>p) p=q;
}
if ((p>=eps)&&(k<7))
{ for (j=0; j<=n-1; j++) u[j]=y[j];
k=k+1; it=1;
}
}
free(b); free(d); free(u); free(v); free(w); free(e);
return;
}
/////////////////////////////////////////////////////////////
static void rkt2(double t,double h,int n,double y[],double b[],double d[],double e[],
void (*gpbs2f)(double t,double y[],int n,double d[]))
{
//extern void gpbs2f();
int i,k;
double a[4],tt;
a[0]=h/2.0; a[1]=a[0]; a[2]=h; a[3]=h;
gpbs2f(t,y,n,d);
for (i=0; i<=n-1; i++) { b[i]=y[i]; e[i]=y[i];}
for (k=0; k<=2; k++)
{ for (i=0; i<=n-1; i++)
{ y[i]=e[i]+a[k]*d[i];
b[i]=b[i]+a[k+1]*d[i]/3.0;
}
tt=t+a[k];
gpbs2f(tt,y,n,d);
}
for (i=0; i<=n-1; i++)
y[i]=b[i]+h*d[i]/6.0;
return;
}
void gpbs2(double t,double h,int n,double y[],double eps,int k,double z[],
void (*gpbs2f)(double t,double y[],int n,double d[]))
{
int i,j,kk,l,m,nn,it;
//void rkt2();
double x,hh,dd,tt,q,p,g[10],*b,*d,*u,*v,*w,*e;
b=(double*)malloc(10*n*sizeof(double));
d=(double*)malloc(n*sizeof(double));
u=(double*)malloc(n*sizeof(double));
v=(double*)malloc(n*sizeof(double));
w=(double*)malloc(n*sizeof(double));
e=(double*)malloc(n*sizeof(double));
for (i=0; i<=n-1; i++) z[i*k]=y[i];
for (i=1; i<=k-1; i++)
{
for (j=0; j<=n-1; j++) v[j]=y[j];
x=t+(i-1)*h; nn=1; hh=h; g[0]=hh;
rkt2(x,hh,n,y,w,d,e,gpbs2f);
for (j=0; j<=n-1; j++)
{ b[j]=y[j]; u[j]=y[j];}
kk=1; it=1;
while (it==1)
{ nn=nn+nn; hh=hh/2.0; it=0;
g[kk]=hh;
for (j=0; j<=n-1; j++) y[j]=v[j];
tt=x;
for (j=0; j<=nn-1; j++)
{ rkt2(t,hh,n,y,w,d,e,gpbs2f);
tt=tt+hh;
}
for (j=0; j<=n-1; j++)
{ dd=y[j]; l=0;
for (m=0; m<=kk-1; m++)
if (l==0)
{ q=dd-b[m*n+j];
if (fabs(q)+1.0==1.0) l=1;
else dd=(g[kk]-g[m])/q;
}
b[kk*n+j]=dd;
if (l!=0) b[kk*n+j]=1.0e+35;
}
for (j=0; j<=n-1; j++)
{ dd=0.0;
for (m=kk-1; m>=0; m--)
dd=-g[m]/(b[(m+1)*n+j]+dd);
y[j]=dd+b[j];
}
p=0.0;
for (j=0; j<=n-1; j++)
{ q=fabs(y[j]-u[j]);
if (q>p) p=q;
}
if ((p>=eps)&&(kk<7))
{ for (j=0; j<=n-1; j++) u[j]=y[j];
kk=kk+1; it=1;
}
}
for (j=0; j<=n-1; j++)
z[j*k+i]=y[j];
}
free(b); free(d); free(u); free(v); free(w); free(e);
return;
}
/////////////////////////////////////////////////////////////
static void rkt3(double t,double h,double y[],int n,double eps,
void (*ggjfqf)(double t,double y[],int n,double d[]))
{
//extern void ggjfqf();
int m,i,j,k;
double hh,p,dt,x,tt,q,a[4],*g,*b,*c,*d,*e;
g=(double*)malloc(n*sizeof(double));
b=(double*)malloc(n*sizeof(double));
c=(double*)malloc(n*sizeof(double));
d=(double*)malloc(n*sizeof(double));
e=(double*)malloc(n*sizeof(double));
hh=h; m=1; p=1.0+eps; x=t;
for (i=0; i<=n-1; i++) c[i]=y[i];
while (p>=eps)
{ a[0]=hh/2.0; a[1]=a[0]; a[2]=hh; a[3]=hh;
for (i=0; i<=n-1; i++)
{ g[i]=y[i]; y[i]=c[i];}
dt=h/m; t=x;
for (j=0; j<=m-1; j++)
{ ggjfqf(t,y,n,d);
for (i=0; i<=n-1; i++)
{ b[i]=y[i]; e[i]=y[i];}
for (k=0; k<=2; k++)
{ for (i=0; i<=n-1; i++)
{ y[i]=e[i]+a[k]*d[i];
b[i]=b[i]+a[k+1]*d[i]/3.0;
}
tt=t+a[k];
ggjfqf(tt,y,n,d);
}
for (i=0; i<=n-1; i++)
y[i]=b[i]+hh*d[i]/6.0;
t=t+dt;
}
p=0.0;
for (i=0; i<=n-1; i++)
{ q=fabs(y[i]-g[i]);
if (q>p) p=q;
}
hh=hh/2.0; m=m+m;
}
free(g); free(b); free(c); free(d); free(e);
return;
}
void ggjfq(double t,double h,int n,double y[],double eps,int k,double z[],
void (*ggjfqf)(double t,double y[],int n,double d[]))
{
//extern void ggjfqf();
//void rkt3();
int i,j;
double a,qq,*d,*p,*u,*v,*w;
d=(double*)malloc(n*sizeof(double));
p=(double*)malloc(n*sizeof(double));
u=(double*)malloc(n*sizeof(double));
v=(double*)malloc(n*sizeof(double));
w=(double*)malloc(n*sizeof(double));
for (i=0; i<=n-1; i++) {p[i]=0.0; z[i*k]=y[i];}
a=t;
ggjfqf(t,y,n,d);
for (j=0; j<=n-1; j++) u[j]=d[j];
rkt3(t,h,y,n,eps,ggjfqf);
t=a+h;
ggjfqf(t,y,n,d);
for (j=0; j<=n-1; j++)
{ z[j*k+1]=y[j]; v[j]=d[j];}
for (j=0; j<=n-1; j++)
{ p[j]=-4.0*z[j*k+1]+5.0*z[j*k]+2.0*h*(2.0*v[j]+u[j]);
y[j]=p[j];
}
t=a+2.0*h;
ggjfqf(t,y,n,d);
for (j=0; j<=n-1; j++)
{ qq=2.0*h*(d[j]-2.0*v[j]-2.0*u[j])/3.0;
qq=qq+4.0*z[j*k+1]-3.0*z[j*k];
z[j*k+2]=(p[j]+qq)/2.0;
y[j]=z[j*k+2];
}
for (i=3; i<=k-1; i++)
{ t=a+(i-1)*h;
ggjfqf(t,y,n,d);
for (j=0; j<=n-1; j++)
{ u[j]=v[j]; v[j]=d[j];}
for (j=0; j<=n-1; j++)
{ qq=-4.0*z[j*k+i-1]+5.0*z[j*k+i-2];
p[j]=qq+2.0*h*(2.0*v[j]+u[j]);
y[j]=p[j];
}
t=t+h;
ggjfqf(t,y,n,d);
for (j=0; j<=n-1; j++)
{ qq=2.0*h*(d[j]-2.0*v[j]-2.0*u[j])/3.0;
qq=qq+4.0*z[j*k+i-1]-3.0*z[j*k+i-2];
y[j]=(p[j]+qq)/2.0;
z[j*k+i]=y[j];
}
}
free(d); free(p); free(u); free(v); free(w);
return;
}
/////////////////////////////////////////////////////////////
static void rkt4(double t,double h,double y[],int n,double eps,
void (*gadmsf)(double t,double y[],int n,double d[]))
{
//extern void gadmsf();
int m,i,j,k;
double hh,p,dt,x,tt,q,a[4],*g,*b,*c,*d,*e;
g=(double*)malloc(n*sizeof(double));
b=(double*)malloc(n*sizeof(double));
c=(double*)malloc(n*sizeof(double));
d=(double*)malloc(n*sizeof(double));
e=(double*)malloc(n*sizeof(double));
hh=h; m=1; p=1.0+eps; x=t;
for (i=0; i<=n-1; i++) c[i]=y[i];
while (p>=eps)
{ a[0]=hh/2.0; a[1]=a[0]; a[2]=hh; a[3]=hh;
for (i=0; i<=n-1; i++)
{ g[i]=y[i]; y[i]=c[i];}
dt=h/m; t=x;
for (j=0; j<=m-1; j++)
{ gadmsf(t,y,n,d);
for (i=0; i<=n-1; i++)
{ b[i]=y[i]; e[i]=y[i];}
for (k=0; k<=2; k++)
{ for (i=0; i<=n-1; i++)
{ y[i]=e[i]+a[k]*d[i];
b[i]=b[i]+a[k+1]*d[i]/3.0;
}
tt=t+a[k];
gadmsf(tt,y,n,d);
}
for (i=0; i<=n-1; i++)
y[i]=b[i]+hh*d[i]/6.0;
t=t+dt;
}
p=0.0;
for (i=0; i<=n-1; i++)
{ q=fabs(y[i]-g[i]);
if (q>p) p=q;
}
hh=hh/2.0; m=m+m;
}
free(g); free(b); free(c); free(d); free(e);
return;
}
void gadms(double t,double h,int n,double y[],double eps,int k,double z[],
void (*gadmsf)(double t,double y[],int n,double d[]))
{
//extern void gadmsf();
//void rkt4();
int i,j,m;
double a,q,*b,*e,*s,*g,*d;
b=(double*)malloc(4*n*sizeof(double));
e=(double*)malloc(n*sizeof(double));
s=(double*)malloc(n*sizeof(double));
g=(double*)malloc(n*sizeof(double));
d=(double*)malloc(n*sizeof(double));
a=t;
for (i=0; i<=n-1; i++) z[i*k]=y[i];
gadmsf(t,y,n,d);
for (i=0; i<=n-1; i++) b[i]=d[i];
for (i=1; i<=3; i++)
if (i<=k-1)
{ t=a+i*h;
rkt4(t,h,y,n,eps,gadmsf);
for (j=0; j<=n-1; j++) z[j*k+i]=y[j];
gadmsf(t,y,n,d);
for (j=0; j<=n-1; j++) b[i*n+j]=d[j];
}
for (i=4; i<=k-1; i++)
{ for (j=0; j<=n-1; j++)
{ q=55.0*b[3*n+j]-59.0*b[2*n+j];
q=q+37.0*b[n+j]-9.0*b[j];
y[j]=z[j*k+i-1]+h*q/24.0;
b[j]=b[n+j];
b[n+j]=b[n+n+j];
b[n+n+j]=b[n+n+n+j];
}
t=a+i*h;
gadmsf(t,y,n,d);
for (m=0; m<=n-1; m++) b[n+n+n+m]=d[m];
for (j=0; j<=n-1; j++)
{ q=9.0*b[3*n+j]+19.0*b[n+n+j]-5.0*b[n+j]+b[j];
y[j]=z[j*k+i-1]+h*q/24.0;
z[j*k+i]=y[j];
}
gadmsf(t,y,n,d);
for (m=0; m<=n-1; m++) b[3*n+m]=d[m];
}
free(b); free(e); free(s); free(g); free(d);
return;
}
/////////////////////////////////////////////////////////////
static void rkt5(double t,double h,double y[],int n,double eps,
void (*ghamgf)(double t,double y[],int n,double d[]))
{
//extern void ghamgf();
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