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comparison liboctave/Array.cc @ 8814:de16ebeef93d

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improve lookup, provide Array<T>::lookup
author Jaroslav Hajek <highegg@gmail.com>
date Thu, 19 Feb 2009 15:19:59 +0100
parents f6dc6eb57045
children eb63fbe60fab
comparison
equal deleted inserted replaced
8813:70d06ed27c08 8814:de16ebeef93d
2379 mode = UNSORTED; 2379 mode = UNSORTED;
2380 } 2380 }
2381 2381
2382 return mode; 2382 return mode;
2383 2383
2384 }
2385
2386 // Do a binary lookup in a sorted array.
2387 template <class T>
2388 octave_idx_type
2389 Array<T>::lookup (const T& value, sortmode mode) const
2390 {
2391 octave_idx_type n = numel ();
2392 octave_sort<T> lsort;
2393
2394 if (mode == UNSORTED)
2395 {
2396 // auto-detect mode
2397 if (n > 1 && lsort.descending_compare (elem (0), elem (n-1)))
2398 mode = DESCENDING;
2399 else
2400 mode = ASCENDING;
2401 }
2402
2403 lsort.set_compare (mode);
2404
2405 return lsort.lookup (data (), n, value);
2406 }
2407
2408 // Ditto, but for an array of values, specializing on long runs.
2409 // Adds optional offset to all indices.
2410 template <class T>
2411 Array<octave_idx_type>
2412 Array<T>::lookup (const Array<T>& values, sortmode mode,
2413 bool linf, bool rinf) const
2414 {
2415 octave_idx_type n = numel ();
2416 octave_sort<T> lsort;
2417 Array<octave_idx_type> idx (values.dims ());
2418
2419 if (mode == UNSORTED)
2420 {
2421 // auto-detect mode
2422 if (n > 1 && lsort.descending_compare (elem (0), elem (n-1)))
2423 mode = DESCENDING;
2424 else
2425 mode = ASCENDING;
2426 }
2427
2428 lsort.set_compare (mode);
2429
2430 // set offset and shift size.
2431 octave_idx_type offset = 0;
2432
2433 if (linf && n > 0)
2434 {
2435 offset++;
2436 n--;
2437 }
2438 if (rinf && n > 0)
2439 n--;
2440
2441 lsort.lookup (data () + offset, n, values.data (), values.numel (),
2442 idx.fortran_vec (), offset);
2443
2444 return idx;
2384 } 2445 }
2385 2446
2386 #define INSTANTIATE_ARRAY_SORT(T) template class octave_sort<T>; 2447 #define INSTANTIATE_ARRAY_SORT(T) template class octave_sort<T>;
2387 2448
2388 #define NO_INSTANTIATE_ARRAY_SORT(T) \ 2449 #define NO_INSTANTIATE_ARRAY_SORT(T) \
2407 { return Array<octave_idx_type> (); } \ 2468 { return Array<octave_idx_type> (); } \
2408 \ 2469 \
2409 template <> sortmode \ 2470 template <> sortmode \
2410 Array<T>::is_sorted_rows (sortmode) const \ 2471 Array<T>::is_sorted_rows (sortmode) const \
2411 { return UNSORTED; } \ 2472 { return UNSORTED; } \
2473 \
2474 template <> octave_idx_type \
2475 Array<T>::lookup (const T&, sortmode) const \
2476 { return 0; } \
2477 template <> Array<octave_idx_type> \
2478 Array<T>::lookup (const Array<T>&, sortmode, bool, bool) const \
2479 { return Array<octave_idx_type> (); } \
2412 2480
2413 2481
2414 2482
2415 template <class T> 2483 template <class T>
2416 Array<T> 2484 Array<T>