You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 

174 lines
4.3 KiB

// eval_rational_series<bool>().
// General includes.
#include "cl_sysdep.h"
// Specification.
#include "cl_LF_tran.h"
// Implementation.
#include "cln/lfloat.h"
#include "cln/integer.h"
#include "cln/exception.h"
#include "cl_LF.h"
namespace cln {
// Subroutine.
// Evaluates S = sum(N1 <= n < N2, a(n)/b(n) * (p(N1)...p(n))/(q(N1)...q(n)))
// and returns P = p(N1)...p(N2-1), Q = q(N1)...q(N2-1), B = B(N1)...B(N2-1)
// and T = B*Q*S (all integers). On entry N1 < N2.
// P will not be computed if a NULL pointer is passed.
static void eval_qb_series_aux (uintC N1, uintC N2,
const cl_qb_series& args,
cl_I* Q, cl_I* B, cl_I* T)
{
switch (N2 - N1) {
case 0:
throw runtime_exception(); break;
case 1:
*Q = args.qv[N1];
*B = args.bv[N1];
*T = 1;
break;
case 2: {
*Q = args.qv[N1] * args.qv[N1+1];
*B = args.bv[N1] * args.bv[N1+1];
*T = args.bv[N1+1] * args.qv[N1+1]
+ args.bv[N1];
break;
}
case 3: {
var cl_I q12 = args.qv[N1+1] * args.qv[N1+2];
*Q = args.qv[N1] * q12;
var cl_I b12 = args.bv[N1+1] * args.bv[N1+2];
*B = args.bv[N1] * b12;
*T = b12 * q12
+ args.bv[N1] * (args.bv[N1+2] * args.qv[N1+2]
+ args.bv[N1+1]);
break;
}
case 4: {
var cl_I q23 = args.qv[N1+2] * args.qv[N1+3];
var cl_I q123 = args.qv[N1+1] * q23;
*Q = args.qv[N1] * q123;
var cl_I b01 = args.bv[N1] * args.bv[N1+1];
var cl_I b23 = args.bv[N1+2] * args.bv[N1+3];
*B = b01 * b23;
*T = b23 * (args.bv[N1+1] * q123
+ args.bv[N1] * q23)
+ b01 * (args.bv[N1+3] * args.qv[N1+3]
+ args.bv[N1+2]);
break;
}
default: {
var uintC Nm = (N1+N2)/2; // midpoint
// Compute left part.
var cl_I LQ, LB, LT;
eval_qb_series_aux(N1,Nm,args,&LQ,&LB,&LT);
// Compute right part.
var cl_I RQ, RB, RT;
eval_qb_series_aux(Nm,N2,args,&RQ,&RB,&RT);
// Put together partial results.
*Q = LQ*RQ;
*B = LB*RB;
// S = LS + 1/LQ * RS, so T = RB*RQ*LT + LB*RT.
*T = RB*RQ*LT + LB*RT;
break;
}
}
}
template<>
const cl_LF eval_rational_series<false> (uintC N, const cl_qb_series& args, uintC len)
{
if (N==0)
return cl_I_to_LF(0,len);
var cl_I Q, B, T;
eval_qb_series_aux(0,N,args,&Q,&B,&T);
return cl_I_to_LF(T,len) / cl_I_to_LF(B*Q,len);
}
static void eval_qb_series_aux (uintC N1, uintC N2,
cl_qb_series_stream& args,
cl_I* Q, cl_I* B, cl_I* T)
{
switch (N2 - N1) {
case 0:
throw runtime_exception(); break;
case 1: {
var cl_qb_series_term v0 = args.next(); // [N1]
*Q = v0.q;
*B = v0.b;
*T = 1;
break;
}
case 2: {
var cl_qb_series_term v0 = args.next(); // [N1]
var cl_qb_series_term v1 = args.next(); // [N1+1]
*Q = v0.q * v1.q;
*B = v0.b * v1.b;
*T = v1.b * v1.q + v0.b;
break;
}
case 3: {
var cl_qb_series_term v0 = args.next(); // [N1]
var cl_qb_series_term v1 = args.next(); // [N1+1]
var cl_qb_series_term v2 = args.next(); // [N1+2]
var cl_I q12 = v1.q * v2.q;
*Q = v0.q * q12;
var cl_I b12 = v1.b * v2.b;
*B = v0.b * b12;
*T = b12 * q12 + v0.b * (v2.b * v2.q + v1.b);
break;
}
case 4: {
var cl_qb_series_term v0 = args.next(); // [N1]
var cl_qb_series_term v1 = args.next(); // [N1+1]
var cl_qb_series_term v2 = args.next(); // [N1+2]
var cl_qb_series_term v3 = args.next(); // [N1+3]
var cl_I q23 = v2.q * v3.q;
var cl_I q123 = v1.q * q23;
*Q = v0.q * q123;
var cl_I b01 = v0.b * v1.b;
var cl_I b23 = v2.b * v3.b;
*B = b01 * b23;
*T = b23 * (v1.b * q123 + v0.b * q23)
+ b01 * (v3.b * v3.q + v2.b);
break;
}
default: {
var uintC Nm = (N1+N2)/2; // midpoint
// Compute left part.
var cl_I LQ, LB, LT;
eval_qb_series_aux(N1,Nm,args,&LQ,&LB,&LT);
// Compute right part.
var cl_I RQ, RB, RT;
eval_qb_series_aux(Nm,N2,args,&RQ,&RB,&RT);
// Put together partial results.
*Q = LQ*RQ;
*B = LB*RB;
// S = LS + 1/LQ * RS, so T = RB*RQ*LT + LB*RT.
*T = RB*RQ*LT + LB*RT;
break;
}
}
}
template<>
const cl_LF eval_rational_series<false> (uintC N, cl_qb_series_stream& args, uintC len)
{
if (N==0)
return cl_I_to_LF(0,len);
var cl_I Q, B, T;
eval_qb_series_aux(0,N,args,&Q,&B,&T);
return cl_I_to_LF(T,len) / cl_I_to_LF(B*Q,len);
}
// Bit complexity (if p(n), q(n), a(n), b(n) have length O(log(n))):
// O(log(N)^2*M(N)).
} // namespace cln