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sym() and vpa() refactor #804

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Merged
cbm755 merged 12 commits into from
Jul 24, 2017
Merged

sym() and vpa() refactor #804

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267f7fe
@sym/sym: fix ratflag 'f' inf/nan by refactoring
cbm755 May 15, 2017
58e05b9
sym and vpa: don't make imaginary units from string 'i' or 'I'
cbm755 May 15, 2017
8e7e40f
vpa: drop const_to_python_str usage
cbm755 May 15, 2017
46153d9
refactor private function
cbm755 May 15, 2017
2fdda3c
@sym/sym: heuristics should look for sqrt(integer) as well
cbm755 May 16, 2017
c55801e
rename private function
cbm755 May 17, 2017
5489ff5
@sym/sym: refactor out the double-to-sym code to some helper fcns
cbm755 May 17, 2017
9b02752
@sym/sym: minor tweak to integer-to-sym conversion
cbm755 May 17, 2017
81dea89
@sym/sym: refactor, simplifying logic by removing a flag
cbm755 May 18, 2017
4bc64da
@sym/sym: private function refactor
cbm755 May 18, 2017
4b02016
@sym/sym: update docs for sqrt(integer) heuristic
cbm755 May 19, 2017
8b11cc5
Merge remote-tracking branch 'origin/master' into sym_vpa_refactor
cbm755 May 20, 2017
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97 changes: 59 additions & 38 deletions inst/@sym/sym.m
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Original file line number Diff line number Diff line change
Expand Up @@ -320,62 +320,80 @@
s = numeric_array_to_sym (x);
return

elseif (isa (x, 'double')) % Handle doubles
elseif (isa (x, 'double')) % Handle double/complex
check = false;

switch ratflag
case 'f'
% TODO: need something like const_to_python_str (x) for inf, nan, not pi
if (isreal (x))
s = python_cmd ('return Rational(_ins[0])', x);
else
s = python_cmd ('return Rational(_ins[0]) + I*Rational(_ins[1])', ...
real (x), imag (x));
end
return
iscmplx = ~isreal (x);
if (iscmplx && isequal (x, 1i))
s = python_cmd ('return S.ImaginaryUnit');
return

@latot latot May 19, 2017

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this part is related to the "check" comment.

elseif (iscmplx)
xx = {real(x); imag(x)};
else
xx = {x};
end
yy = cell(2, 1);

case 'r'
iscmplx = ~isreal (x);
if (iscmplx)
xx = {real(x); imag(x)};
else
xx = {x};
end
ss = cell(2, 1);
for n = 1:numel (xx)
x = xx{n};

switch ratflag
case 'f'
if (isnan (x))
y = python_cmd ('return S.NaN');
elseif (isinf (x) && x > 0)
y = python_cmd ('return S.Infinity');
elseif (isinf (x))
y = python_cmd ('return -S.Infinity');
else
% Rational will exactly convert from a float
y = python_cmd ('return Rational(_ins[0])', x);
end

for n = 1:numel (xx)
tmpx = xx{n};
[ss{n}, flag] = const_to_python_str (tmpx);
if (~flag)
case 'r'
if (isnan (x))
y = python_cmd ('return S.NaN');
elseif (isinf (x) && x < 0)
y = python_cmd ('return -S.Infinity');
elseif (isinf (x))
y = python_cmd ('return S.Infinity');
elseif (isequal (x, pi))
% special case
y = python_cmd ('return S.Pi');
elseif (isequal (x, -pi))
% special case
y = python_cmd ('return -S.Pi');
elseif ((abs (x) < flintmax) && (mod (x, 1) == 0))
y = python_cmd ('return S(_ins[0])', int64 (x));
else
% Allow 1/3 and other "small" fractions.
% Personally, I like a warning here so I can catch bugs.
% Matlab SMT does this (w/o warning).
if (ratwarn)
warning('OctSymPy:sym:rationalapprox', ...
'passing floating-point values to sym is dangerous, see "help sym"');
end
[N1, D1] = rat (tmpx);
[N2, D2] = rat (tmpx / pi);
[N1, D1] = rat (x);
[N2, D2] = rat (x / pi);
if (10*abs (D2) < abs (D1))
% use frac*pi if demoninator significantly shorter
ss{n} = sprintf ('Rational(%s, %s)*pi', num2str (N2), num2str (D2));
y = python_cmd ('return Rational(*_ins)*S.Pi', int64 (N2), int64 (D2));
else
ss{n} = sprintf ('Rational(%s, %s)', num2str (N1), num2str (D1));
y = python_cmd ('return Rational(*_ins)', int64 (N1), int64 (D1));
end
else
ss{n} = sprintf ('S(%s)', ss{n});
end
end

if (iscmplx)
x = sprintf ('%s + I*(%s)', ss{1}, ss{2});
else
x = ss{1};
end

otherwise
error ('sym: this case should not be possible')
otherwise
error ('sym: this case should not be possible')
end
yy{n} = y;
end
if (iscmplx)
s = yy{1} + yy{2}*1i;
else
s = yy{1};
end
return

elseif (islogical (x)) % Handle logical values
check = false;
Expand Down Expand Up @@ -804,6 +822,9 @@
%! assert (isequal (sym(inf, 'f'), sym(inf)))
%! assert (isequal (sym(-inf, 'f'), sym(-inf)))
%! assert (isequaln (sym(nan, 'f'), sym(nan)))
%! assert (isequal (sym(complex(inf, -inf), 'f'), sym(complex(inf, -inf))))
%! assert (isequaln (sym(complex(nan, inf), 'f'), sym(complex(nan, inf))))
%! assert (isequaln (sym(complex(-inf, nan), 'f'), sym(complex(-inf, nan))))

%!test
%! % symbols with special sympy names
Expand Down