comparison src/fftw-3.3.5/dft/generic.c @ 42:2cd0e3b3e1fd

Current fftw source

+/*
+ * Copyright (c) 2003, 2007-14 Matteo Frigo
+ * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#include "dft.h"
+
+typedef struct {
+     solver super;
+} S;
+
+typedef struct {
+     plan_dft super;
+     twid *td;
+     INT n, is, os;
+} P;
+
+
+static void cdot(INT n, const E *x, const R *w, 
+		 R *or0, R *oi0, R *or1, R *oi1)
+{
+     INT i;
+
+     E rr = x[0], ri = 0, ir = x[1], ii = 0; 
+     x += 2;
+     for (i = 1; i + i < n; ++i) {
+	  rr += x[0] * w[0];
+	  ir += x[1] * w[0];
+	  ri += x[2] * w[1];
+	  ii += x[3] * w[1];
+	  x += 4; w += 2;
+     }
+     *or0 = rr + ii;
+     *oi0 = ir - ri;
+     *or1 = rr - ii;
+     *oi1 = ir + ri;
+}
+
+static void hartley(INT n, const R *xr, const R *xi, INT xs, E *o,
+		    R *pr, R *pi)
+{
+     INT i;
+     E sr, si;
+     o[0] = sr = xr[0]; o[1] = si = xi[0]; o += 2;
+     for (i = 1; i + i < n; ++i) {
+	  sr += (o[0] = xr[i * xs] + xr[(n - i) * xs]);
+	  si += (o[1] = xi[i * xs] + xi[(n - i) * xs]);
+	  o[2] = xr[i * xs] - xr[(n - i) * xs];
+	  o[3] = xi[i * xs] - xi[(n - i) * xs];
+	  o += 4;
+     }
+     *pr = sr;
+     *pi = si;
+}
+		    
+static void apply(const plan *ego_, R *ri, R *ii, R *ro, R *io)
+{
+     const P *ego = (const P *) ego_;
+     INT i;
+     INT n = ego->n, is = ego->is, os = ego->os;
+     const R *W = ego->td->W;
+     E *buf;
+     size_t bufsz = n * 2 * sizeof(E);
+
+     BUF_ALLOC(E *, buf, bufsz);
+     hartley(n, ri, ii, is, buf, ro, io);
+
+     for (i = 1; i + i < n; ++i) {
+	  cdot(n, buf, W,
+	       ro + i * os, io + i * os,
+	       ro + (n - i) * os, io + (n - i) * os);
+	  W += n - 1;
+     }
+
+     BUF_FREE(buf, bufsz);
+}
+
+static void awake(plan *ego_, enum wakefulness wakefulness)
+{
+     P *ego = (P *) ego_;
+     static const tw_instr half_tw[] = {
+	  { TW_HALF, 1, 0 },
+	  { TW_NEXT, 1, 0 }
+     };
+
+     X(twiddle_awake)(wakefulness, &ego->td, half_tw, ego->n, ego->n,
+		      (ego->n - 1) / 2);
+}
+
+static void print(const plan *ego_, printer *p)
+{
+     const P *ego = (const P *) ego_;
+
+     p->print(p, "(dft-generic-%D)", ego->n);
+}
+
+static int applicable(const solver *ego, const problem *p_, 
+		      const planner *plnr)
+{
+     const problem_dft *p = (const problem_dft *) p_;
+     UNUSED(ego);
+
+     return (1
+	     && p->sz->rnk == 1
+	     && p->vecsz->rnk == 0
+	     && (p->sz->dims[0].n % 2) == 1 
+	     && CIMPLIES(NO_LARGE_GENERICP(plnr), p->sz->dims[0].n < GENERIC_MIN_BAD)
+	     && CIMPLIES(NO_SLOWP(plnr), p->sz->dims[0].n > GENERIC_MAX_SLOW)
+	     && X(is_prime)(p->sz->dims[0].n)
+	  );
+}
+
+static plan *mkplan(const solver *ego, const problem *p_, planner *plnr)
+{
+     const problem_dft *p;
+     P *pln;
+     INT n;
+
+     static const plan_adt padt = {
+	  X(dft_solve), awake, print, X(plan_null_destroy)
+     };
+
+     if (!applicable(ego, p_, plnr))
+          return (plan *)0;
+
+     pln = MKPLAN_DFT(P, &padt, apply);
+
+     p = (const problem_dft *) p_;
+     pln->n = n = p->sz->dims[0].n;
+     pln->is = p->sz->dims[0].is;
+     pln->os = p->sz->dims[0].os;
+     pln->td = 0;
+
+     pln->super.super.ops.add = (n-1) * 5;
+     pln->super.super.ops.mul = 0;
+     pln->super.super.ops.fma = (n-1) * (n-1) ;
+#if 0 /* these are nice pipelined sequential loads and should cost nothing */
+     pln->super.super.ops.other = (n-1)*(4 + 1 + 2 * (n-1));  /* approximate */
+#endif
+
+     return &(pln->super.super);
+}
+
+static solver *mksolver(void)
+{
+     static const solver_adt sadt = { PROBLEM_DFT, mkplan, 0 };
+     S *slv = MKSOLVER(S, &sadt);
+     return &(slv->super);
+}
+
+void X(dft_generic_register)(planner *p)
+{
+     REGISTER_SOLVER(p, mksolver());
+}