I can't use SR(sage_eval(' expression')) Now all my integral are failing.
Here is an example
>sage
│ SageMath version 9.8, Release Date: 2023-02-11 │
│ Using Python 3.11.1. Type "help()" for help. │
sage: var('x')
x
sage: SR(sage_eval('sin(x)'))
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
Cell In [3], line 1
----> 1 SR(sage_eval('sin(x)'))
File ~/TMP/sage-9.8/src/sage/misc/sage_eval.py:198, in sage_eval(source,
locals, cmds, preparse)
196 return locals['_sage_eval_returnval_']
197 else:
--> 198 return eval(source, sage.all.__dict__, locals)
File <string>:1
NameError: name 'x' is not defined
But
sage: SR('sin(x)')
sin(x)
Works.
So adding sage_eval() did not work.
--Nasser
On Wednesday, April 26, 2023 at 1:33:26 AM UTC-5 Nils Bruin wrote:
> I think the problem is that the SR exression parses does not know about
> python's "(a,b)" tuple notation. If you replace the round brackets with
> square brackets, it does seem to work; at least for the example you give:
>
> sage: SR('hypergeometric([3/2,], [5/2, 3], -1/4*3^2)')
> hypergeometric((3/2,), (5/2, 3), -1/4*3^2)
>
> You could use the python parser instead, via something like:
>
> SR(sage_eval(' hypergeometric((3/2,), (5/2, 3), -1/4*3^2)'))
>
> but note that SR will happily define symbols it doesn't know, whereas
> sage_eval will complain:
>
> sage: SR("my_function(var1,var2)")
> my_function(var1, var2)
> sage: SR(sage_eval("my_function(var1,var2)"))
> NameError: name 'my_function' is not defined
>
>
>
> On Tuesday, 25 April 2023 at 23:08:02 UTC-7 Nasser M. Abbasi wrote:
>
>> I read integrals from a file. They all are stored as strings.
>>
>> Then use SR('expression') inside sagemath to convert them to sagemath
>> symbolic expression before calling integrate.
>>
>> Some give parsing error.
>>
>> Is using SR('expression') not the correct way to convert string to a
>> symbolic expression?
>>
>> I am using 9.8 on Linux. Here is an example
>>
>> >sage
>> │ SageMath version 9.8, Release Date: 2023-02-11 │
>> │ Using Python 3.11.1. Type "help()" for help. │
>>
>> sage: hypergeometric((3/2,), (5/2, 3), -1/4*3^2)
>> hypergeometric((3/2,), (5/2, 3), -9/4)
>>
>> You see, there is no error. But now if put the expression inside string
>> and use SR, it gives error:
>>
>>
>> sage: SR('hypergeometric((3/2,), (5/2, 3), -1/4*3^2)')
>>
>> ---------------------------------------------------------------------------
>> SyntaxError Traceback (most recent call
>> last)
>> File ~/TMP/sage-9.8/src/sage/symbolic/expression.pyx:13706, in
>> sage.symbolic.expression.new_Expression()
>> 13705 from sage.calculus.calculus import
>> symbolic_expression_from_string
>> > 13706 return parent(symbolic_expression_from_string(x))
>> 13707 except SyntaxError as err:
>>
>> File ~/TMP/sage-9.8/src/sage/calculus/calculus.py:2578, in
>> symbolic_expression_from_string(s, syms, accept_sequence, parser)
>> 2576 parser._callable_constructor().set_names({k[0]: v for k, v in
>> syms.items()
>> 2577 if _is_function(v)})
>> -> 2578 return parse_func(s)
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:556, in
>> sage.misc.parser.Parser.parse_expression()
>> 555
>> --> 556 cpdef parse_expression(self, s):
>> 557 """
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:568, in
>> sage.misc.parser.Parser.parse_expression()
>> 567 cdef Tokenizer tokens = Tokenizer(s)
>> --> 568 expr = self.p_expr(tokens)
>> 569 if tokens.next() != EOS:
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:792, in
>> sage.misc.parser.Parser.p_expr()
>> 791 cdef int op
>> --> 792 operand1 = self.p_term(tokens)
>> 793 op = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:826, in
>> sage.misc.parser.Parser.p_term()
>> 825 cdef int op
>> --> 826 operand1 = self.p_factor(tokens)
>> 827 op = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:869, in
>> sage.misc.parser.Parser.p_factor()
>> 868 tokens.backtrack()
>> --> 869 return self.p_power(tokens)
>> 870
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:897, in
>> sage.misc.parser.Parser.p_power()
>> 896 """
>> --> 897 operand1 = self.p_atom(tokens)
>> 898 cdef int token = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:952, in
>> sage.misc.parser.Parser.p_atom()
>> 951 func = self.callable_constructor(name)
>> --> 952 args, kwds = self.p_args(tokens)
>> 953 token = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:989, in
>> sage.misc.parser.Parser.p_args()
>> 988 while token == c',':
>> --> 989 arg = self.p_arg(tokens)
>> 990 if isinstance(arg, tuple):
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:1039, in
>> sage.misc.parser.Parser.p_arg()
>> 1038 tokens.backtrack()
>> -> 1039 return self.p_expr(tokens)
>> 1040
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:792, in
>> sage.misc.parser.Parser.p_expr()
>> 791 cdef int op
>> --> 792 operand1 = self.p_term(tokens)
>> 793 op = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:826, in
>> sage.misc.parser.Parser.p_term()
>> 825 cdef int op
>> --> 826 operand1 = self.p_factor(tokens)
>> 827 op = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:869, in
>> sage.misc.parser.Parser.p_factor()
>> 868 tokens.backtrack()
>> --> 869 return self.p_power(tokens)
>> 870
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:897, in
>> sage.misc.parser.Parser.p_power()
>> 896 """
>> --> 897 operand1 = self.p_atom(tokens)
>> 898 cdef int token = tokens.next()
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:964, in
>> sage.misc.parser.Parser.p_atom()
>> 963 if token != c')':
>> --> 964 self.parse_error(tokens, "Mismatched parentheses")
>> 965 return expr
>>
>> File ~/TMP/sage-9.8/src/sage/misc/parser.pyx:1042, in
>> sage.misc.parser.Parser.parse_error()
>> 1041 cdef parse_error(self, Tokenizer tokens, msg="Malformed
>> expression"):
>> -> 1042 raise SyntaxError(msg, tokens.s, tokens.pos)
>> 1043
>>
>> SyntaxError: Mismatched parentheses
>>
>> During handling of the above exception, another exception occurred:
>>
>> TypeError Traceback (most recent call
>> last)
>> Cell In [19], line 1
>> ----> 1 SR('hypergeometric((3/2,), (5/2, 3), -1/4*3^2)')
>>
>> File ~/TMP/sage-9.8/src/sage/structure/parent.pyx:896, in
>> sage.structure.parent.Parent.__call__()
>> 894 if mor is not None:
>> 895 if no_extra_args:
>> --> 896 return mor._call_(x)
>> 897 else:
>> 898 return mor._call_with_args(x, args, kwds)
>>
>> File ~/TMP/sage-9.8/src/sage/structure/coerce_maps.pyx:161, in
>> sage.structure.coerce_maps.DefaultConvertMap_unique._call_()
>> 159 print(type(C), C)
>> 160 print(type(C._element_constructor),
>> C._element_constructor)
>> --> 161 raise
>> 162
>> 163 cpdef Element _call_with_args(self, x, args=(), kwds={}):
>>
>> File ~/TMP/sage-9.8/src/sage/structure/coerce_maps.pyx:156, in
>> sage.structure.coerce_maps.DefaultConvertMap_unique._call_()
>> 154 cdef Parent C = self._codomain
>> 155 try:
>> --> 156 return C._element_constructor(x)
>> 157 except Exception:
>> 158 if print_warnings:
>>
>> File ~/TMP/sage-9.8/src/sage/symbolic/ring.pyx:384, in
>> sage.symbolic.ring.SymbolicRing._element_constructor_()
>> 382 TypeError: Malformed expression: λ + * !!! 1
>> 383 """
>> --> 384 return new_Expression(self, x)
>> 385
>> 386 def _force_pyobject(self, x, bint force=False, bint
>> recursive=True):
>>
>> File ~/TMP/sage-9.8/src/sage/symbolic/expression.pyx:13709, in
>> sage.symbolic.expression.new_Expression()
>> 13707 except SyntaxError as err:
>> 13708 msg, s, pos = err.args
>> > 13709 raise TypeError("%s: %s !!! %s" % (msg, s[:pos], s[pos:]))
>> 13710
>> 13711 from sage.rings.infinity import (infinity, minus_infinity,
>>
>> TypeError: Mismatched parentheses: hypergeometric((3/2, !!! ), (5/2, 3),
>> -1/4*3^2)
>> sage:
>>
>>
>>
>> Is this a bug or Am I doing something wrong? This happens on very few
>> cases, not all the time. The above is an example where SR gives an error.
>>
>> Thanks
>> --Nasser
>>
>>
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