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comparison liboctave/Array.cc @ 11242:0090bb47d0b5

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simplify special case for concatenation of empty matrices
author John W. Eaton <jwe@octave.org>
date Fri, 12 Nov 2010 13:19:24 -0500
parents 80e01d79cf80
children c3ad80f4ce36
comparison
equal deleted inserted replaced
11241:80e01d79cf80 11242:0090bb47d0b5
2535 else if (n == 0) 2535 else if (n == 0)
2536 return Array<T> (); 2536 return Array<T> ();
2537 2537
2538 // Special case: 2538 // Special case:
2539 // 2539 //
2540 // cat (dim, [], ..., [], A) 2540 // cat (dim, [], ..., [], A, ...)
2541 // 2541 //
2542 // with dim > 2, A not 0x0, and at least three arguments to 2542 // with dim > 2, A not 0x0, and at least three arguments to
2543 // concatenate results in A. Note that this check must be performed 2543 // concatenate is equivalent to
2544 // here because for full-on braindead Matlab compatibility, we need 2544 //
2545 // the above to succeed, but things like 2545 // cat (dim, A, ...)
2546 //
2547 // Note that this check must be performed here because for full-on
2548 // braindead Matlab compatibility, we need to have things like
2549 //
2550 // cat (3, [], [], A)
2551 //
2552 // succeed, but to have things like
2546 // 2553 //
2547 // cat (3, cat (3, [], []), A) 2554 // cat (3, cat (3, [], []), A)
2548 // cat (3, zeros (0, 0, 2), A) 2555 // cat (3, zeros (0, 0, 2), A)
2549 // 2556 //
2550 // to fail. See also bug report #31615. 2557 // fail. See also bug report #31615.
2558
2559 octave_idx_type istart = 0;
2551 2560
2552 if (n > 2 && dim > 1) 2561 if (n > 2 && dim > 1)
2553 { 2562 {
2554 dim_vector dv = array_list[n-1].dims (); 2563 for (octave_idx_type i = 0; i < n; i++)
2555 2564 {
2556 if (! dv.zero_by_zero ()) 2565 dim_vector dv = array_list[i].dims ();
2557 { 2566
2558 bool all_but_last_are_zero_by_zero = true; 2567 if (dv.zero_by_zero ())
2559 2568 istart++;
2560 if (all_but_last_are_zero_by_zero) 2569 else
2561 { 2570 break;
2562 for (octave_idx_type i = 0; i < n-1; i++) 2571 }
2563 { 2572
2564 dim_vector dv = array_list[i].dims (); 2573 // Don't skip any initial aguments if they are all empty.
2565 2574 if (istart >= n)
2566 if (! dv.zero_by_zero ()) 2575 istart = 0;
2567 { 2576 }
2568 all_but_last_are_zero_by_zero = false; 2577
2569 break; 2578 dim_vector dv = array_list[istart++].dims ();
2570 } 2579
2571 } 2580 for (octave_idx_type i = istart; i < n; i++)
2572 }
2573
2574 if (all_but_last_are_zero_by_zero)
2575 return array_list[n-1];
2576 }
2577 }
2578
2579
2580 dim_vector dv = array_list[0].dims ();
2581
2582 for (octave_idx_type i = 1; i < n; i++)
2583 if (! (dv.*concat_rule) (array_list[i].dims (), dim)) 2581 if (! (dv.*concat_rule) (array_list[i].dims (), dim))
2584 (*current_liboctave_error_handler) 2582 (*current_liboctave_error_handler)
2585 ("cat: dimension mismatch"); 2583 ("cat: dimension mismatch");
2586 2584
2587 Array<T> retval (dv); 2585 Array<T> retval (dv);