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comparison scripts/special-matrix/gallery.m @ 18880:3d33fe79816c

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gallery.m: Return correct matrix if 3rd argument is not specified. * gallery.m (triw): Change default of final argument to k=n-1, rather than k = -1. Add input validation to test that k >=0.
author Rik <rik@octave.org>
date Thu, 19 Jun 2014 10:35:39 -0700
parents 9ac2357f19bc
children 0850b5212619
comparison
equal deleted inserted replaced
18877:30d8501a857a 18880:3d33fe79816c
2518 ## T = diag (x, -1) + diag (y) + diag (z, 1); # For non-sparse matrix. 2518 ## T = diag (x, -1) + diag (y) + diag (z, 1); # For non-sparse matrix.
2519 n = numel (y); 2519 n = numel (y);
2520 T = spdiags ([[x;0] y [0;z]], -1:1, n, n); 2520 T = spdiags ([[x;0] y [0;z]], -1:1, n, n);
2521 endfunction 2521 endfunction
2522 2522
2523 function t = triw (n, alpha = -1, k = -1) 2523 function t = triw (n, alpha = -1, k = n(end) - 1)
2524 ## TRIW Upper triangular matrix discussed by Wilkinson and others. 2524 ## TRIW Upper triangular matrix discussed by Wilkinson and others.
2525 ## TRIW(N, ALPHA, K) is the upper triangular matrix with ones on 2525 ## TRIW(N, ALPHA, K) is the upper triangular matrix with ones on
2526 ## the diagonal and ALPHAs on the first K >= 0 superdiagonals. 2526 ## the diagonal and ALPHAs on the first K >= 0 superdiagonals.
2527 ## N may be a 2-vector, in which case the matrix is N(1)-by-N(2) and 2527 ## N may be a 2-vector, in which case the matrix is N(1)-by-N(2) and
2528 ## upper trapezoidal. 2528 ## upper trapezoidal.
2554 error ("gallery: 1 to 3 arguments are required for triw matrix."); 2554 error ("gallery: 1 to 3 arguments are required for triw matrix.");
2555 elseif (! isnumeric (n) || all (numel (n) != [1 2])) 2555 elseif (! isnumeric (n) || all (numel (n) != [1 2]))
2556 error ("gallery: N must be a 1 or 2 elements vector for triw matrix."); 2556 error ("gallery: N must be a 1 or 2 elements vector for triw matrix.");
2557 elseif (! isscalar (alpha)) 2557 elseif (! isscalar (alpha))
2558 error ("gallery: ALPHA must be a scalar for triw matrix."); 2558 error ("gallery: ALPHA must be a scalar for triw matrix.");
2559 elseif (! isscalar (k) || ! isnumeric (k) || fix (k) != k) 2559 elseif (! isscalar (k) || ! isnumeric (k) || fix (k) != k || k < 0)
2560 error ("gallery: K must be a numeric integer for triw matrix."); 2560 error ("gallery: K must be a numeric integer >= 0 for triw matrix.");
2561 endif 2561 endif
2562 2562
2563 m = n(1); # Parameter n specifies dimension: m-by-n. 2563 m = n(1); # Parameter n specifies dimension: m-by-n.
2564 n = n(end); 2564 n = n(end);
2565 2565