Added special-case logical-indexing function * logical-index.h (New file) : Logical-indexing function. May be called on octave_value types via call_bool_index * nz-iterators.h : Add base-class nz_iterator for iterator types. Array has template bool for whether to internally store row-col or compute on the fly Add skip_ahead method which skips forward to the next nonzero after its argument Add flat_index for computing octave_idx_type index of current position (with assertion failure in the case of overflow) Move is_zero to separate file * ov-base-diag.cc, ov-base-mat.cc, ov-base-sparse.cc, ov-perm.cc (do_index_op): Add call to call_bool_index in logical-index.h * Array.h : Move forward-declaration for array_iterator to separate header file * dim-vector.cc (dim_max): Refers to idx-bounds.h (max_idx) * array-iter-decl.h (New file): Header file for forward declaration of array-iterator * direction.h : Add constants fdirc and bdirc to avoid having to reconstruct them * dv-utils.h, dv-utils.cc (New files) : Utility functions for querying and constructing dim-vectors * idx-bounds.h (New file) : Utility constants and functions for determining whether things will overflow the maximum allowed bounds * interp-idx.h (New function : to_flat_idx) : Converts row-col pair to linear index of octave_idx_type * is-zero.h (New file) : Function for determining whether an element is zero * logical-index.tst : Add tests for correct return-value dimensions and large sparse matrix behavior

#include <octave/oct.h>

DEFUN_DLD (oregonator, args, ,
           "The `oregonator'.\n\
\n\
Reference:\n\
\n\
  Oscillations in chemical systems.  IV.  Limit cycle behavior in a\n\
  model of a real chemical reaction. Richard J. Field and Richard\n\
  M. Noyes, The Journal of Chemical Physics, Volume 60 Number 5,\n\
  March 1974.")
{
  ColumnVector dx (3);

  ColumnVector x (args(0).vector_value ());

  dx(0) = 77.27 * (x(1) - x(0)*x(1) + x(0) - 8.375e-06*pow (x(0), 2.0));
  dx(1) = (x(2) - x(0)*x(1) - x(1)) / 77.27;
  dx(2) = 0.161*(x(0) - x(2));

  return octave_value (dx);
}