Merge pull request #704 from cbm755/cbm_594_part1

sym constructor rewrite (594 Part 1)

NEWS

@@ -40,6 +40,8 @@ octsympy 2.5.0-dev
 
   * `solve` now works with inequalities.
 
+  * `sym('1.3')` now creates the rational number 13/10.
+
   * Update minimum versions of SymPy to 1.0 and Octave to 4.0.0, so
     we can remove some crufty workarounds.
 

inst/@sym/private/cell_array_to_sym.m

@@ -16,21 +16,21 @@
 %% License along with this software; see the file COPYING.
 %% If not, see <http://www.gnu.org/licenses/>.
 
-function s = cell_array_to_sym (L)
+function s = cell_array_to_sym (L, varargin)
 %private helper for sym ctor
 %   convert a cell array to syms, recursively when nests cells found
 
-  assert(iscell(L))
+  assert (iscell (L))
 
-  s = cell(size(L));
+  s = cell (size (L));
 
-  for i = 1:numel(L)
+  for i = 1:numel (L)
     %s{i} = sym(L{i});
     % not strictly necessary if sym calls this but maybe neater this way:
     item = L{i};
-    if iscell(item)
-      s{i} = cell_array_to_sym(item);
+    if iscell (item)
+      s{i} = cell_array_to_sym (item, varargin{:});
     else
-      s{i} = sym(item);
+      s{i} = sym (item, varargin{:});
     end
   end

inst/@sym/private/check_assumptions.m

@@ -0,0 +1,61 @@
+%% Copyright (C) 2016 Lagu
+%%
+%% This file is part of OctSymPy.
+%%
+%% OctSymPy 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 3 of the License,
+%% or (at your option) any later version.
+%%
+%% This software 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 software; see the file COPYING.
+%% If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @deftypefun check_assumptions (@var{x})
+%% Check if the input have valid assumptions.
+%%
+%% Private helper function.
+%%
+%% @seealso{sym}
+%% @end deftypefun
+
+
+function check_assumptions (x)
+
+  ca_helper (x)
+
+end
+
+%% Is safer use a helper when private functions call it self for classdef.
+function ca_helper (x)
+
+  persistent valid_asm
+
+  if (isempty (valid_asm))
+    valid_asm = assumptions ('possible');
+  end
+
+  if (~islogical (x))
+    if (isa (x, 'char'))
+      assert (ismember (x, valid_asm), ['sym: the assumption "' x '" is not supported in your Sympy version.'])
+    elseif (isstruct (x))
+      fields = fieldnames (x);
+      for j = 1:numel (fields)
+        ca_helper (fields{j})
+      end
+    elseif (iscell (x))
+      for j = 1:length (x)
+        ca_helper (x{j})
+      end
+    else
+      error ('sym: assumption must be a string or struct or cell')
+    end
+  end
+
+end

inst/@sym/private/const_to_python_str.m

@@ -0,0 +1,101 @@
+%% Copyright (C) 2015, 2016 Colin B. Macdonald
+%% Copyright (C) 2016 Lagu
+%%
+%% This file is part of OctSymPy.
+%%
+%% OctSymPy 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 3 of the License,
+%% or (at your option) any later version.
+%%
+%% This software 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 software; see the file COPYING.
+%% If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @deftypefun {[@var{s}, @var{flag}] =} const_to_python_str (@var{x})
+%% Recognize constant and return their python string equivalent.
+%%
+%% Private helper function.
+%%
+%% Caution: there are two copies of this file for technical
+%% reasons: make sure you modify both of them!
+%%
+%% @seealso{sym, vpa}
+%% @end deftypefun
+
+function [s, flag] = const_to_python_str (x)
+
+  persistent list
+  persistent const
+
+  if (isempty (list))
+    % Table of special doubles and special strings.  Format for each row is:
+    %    double value, {list of strings to recognize}, resulting python expr
+    % Note: case senstive
+    % Note: python expr should be in list for identity "sym(sympr(x)) == x"
+    list = {pi {'pi'} 'pi'; ...
+            inf {'inf' 'Inf' 'oo'} 'oo'; ...
+            nan {'NaN' 'nan'} 'nan'; ...
+            i {'i' 'I'} 'I'};
+    % Special Sympy constants to recognize
+    const = {'zoo'};
+  end
+
+  flag = 1;
+
+  if (isa (x, 'double'))  % Number comparison
+    for j = 1:length (list)
+      if (isequaln (x, list{j, 1}))
+        s = list{j, 3};
+        return
+      elseif (isequaln (x, -list{j, 1}))
+        s = ['-' list{j, 3}];
+        return
+      end
+    end
+  elseif (isa (x, 'char'))  % Char comparison
+    for j = 1:length (list)
+      for n = 1:length (list{j, 2})
+        if (strcmp (x, list{j, 2}{n}) || strcmp (x, ['+' list{j, 2}{n}]))
+          s = list{j, 3};
+          return
+        elseif (strcmp (x, ['-' list{j, 2}{n}]))
+          s = ['-' list{j, 3}];
+          return
+        end
+      end
+    end
+    for j = 1:length (const)   % Check if is a python constant
+      if (strcmp (x, const{j}) || strcmp (x, ['+' const{j}]))
+        s = const{j};
+        return
+      elseif (strcmp (x, ['-' const{j}]))
+        s = ['-' const{j}];
+        return
+      end
+    end
+  else
+    error ('Format not supported.')
+  end
+
+  if (isa (x, 'char'))
+    flag = 0;
+    s = x;
+    return
+  elseif (isa (x, 'double'))
+    if ((abs (x) < 1e15) && (mod (x,1) == 0))
+      % special treatment for "small" integers
+      s = num2str (x);  % better than sprintf('%d', large)
+    else
+      s = '';
+      flag = 0;
+    end
+  end
+
+end