Re: [sympy] Equivalence test
Am 09.02.2015 um 20:40 schrieb Ondřej Čertík: We can call it zero_numerical or something like that (test_numerically, ...). Mathematica calls this PossibleZeroQ stochastically_zero, maybe? To highlight that it's a probabilistic test, not a guaranteed-to-be-correct one. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/54D9D9F6.8040503%40durchholz.org. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
Having seen expressions that are hard to simplify into the same form, I'd say that it has a place in SymPy (there's even a utilities directory). That said, I'd probably suggest a name like nequiv similar to nsolve. Cheers, Tim. On 2015-02-09, at 11:09 AM, Peter Chervenski spoo...@abv.bg wrote: I made this function to test for the equivalence of two expressions. It doesn't really prove anything, but if the tests are many, the probability of it being wrong becomes negligible. Do such utility functions have a place in SymPy? def equiv(a, b, ntests=15): Test if expression a is equivalent to b by comparing the results of many random numeric tests # get the symbols sb_a = filter(lambda x: x.is_Symbol, a.atoms()) sb_b = filter(lambda x: x.is_Symbol, b.atoms()) sb = list(set(sb_a + sb_b)) eq = True for i in xrange(ntests): k = dict(zip(sb, np.random.randn(len(sb r_a = a.subs( k ) r_b = b.subs( k ) # prove there is a difference if (r_a - r_b)**2 1e-30: # not the same? the expressions are different eq = False break return eq -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/58700b18-624c-4723-935a-dd71bb30d738%40googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/EDA65D41-14BB-4475-B4C9-AEF1588490DD%40gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
At that point in the routine we know the expression is constant so either it is zero or it is some other constant. So a set or random values for symbols is computed and if it is *not* zero we have an answer, otherwise we have to work harder to try *prove* that it's zero. See also the discussion in https://github.com/sympy/sympy/issues/8516 and the routine I wrote there in response at https://github.com/sympy/sympy/pull/8561 /c On Monday, February 9, 2015 at 5:46:51 PM UTC-6, Aaron Meurer wrote: I'm unclear what this line is doing https://github.com/sympy/sympy/blob/e015652bf34987128bca3176d1c939fbd0d486cf/sympy/core/expr.py#L613. It looks like it evaluates it, at least in some cases. Probably Chris Smith could give a more definite answer. Aaron Meurer On Mon, Feb 9, 2015 at 5:20 PM, Ondřej Čertík ondrej...@gmail.com javascript: wrote: On Mon, Feb 9, 2015 at 4:15 PM, Aaron Meurer asme...@gmail.com javascript: wrote: On Mon, Feb 9, 2015 at 5:11 PM, Ondřej Čertík ondrej...@gmail.com javascript: wrote: On Mon, Feb 9, 2015 at 3:37 PM, Aaron Meurer asme...@gmail.com javascript: wrote: Doesn't expr.equals also do something similar to this? No, that uses symbolics (thus it is not able to check complex expressions or it will be slow). Btw, you already asked this exact question here: https://github.com/sympy/sympy/pull/8036#issuecomment-55969269 and my answer is right below it. Heh. But I seem to remember equals plugging in values. Maybe it used to do it, but doesn't any more? The code is here: https://github.com/sympy/sympy/blob/e015652bf34987128bca3176d1c939fbd0d486cf/sympy/core/expr.py#L563 Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+un...@googlegroups.com javascript:. To post to this group, send email to sy...@googlegroups.com javascript:. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVCB2Ftb_bAQUNnh2F%3DeHZA_Oy1dOrTn7W5ApkfATfOpsQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/514c7d89-1ecb-4cf2-b392-0891af33e31e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
Hi Peter, On Mon, Feb 9, 2015 at 9:09 AM, Peter Chervenski spoo...@abv.bg wrote: I made this function to test for the equivalence of two expressions. It doesn't really prove anything, but if the tests are many, the probability of it being wrong becomes negligible. Do such utility functions have a place in SymPy? def equiv(a, b, ntests=15): Test if expression a is equivalent to b by comparing the results of many random numeric tests # get the symbols sb_a = filter(lambda x: x.is_Symbol, a.atoms()) sb_b = filter(lambda x: x.is_Symbol, b.atoms()) sb = list(set(sb_a + sb_b)) eq = True for i in xrange(ntests): k = dict(zip(sb, np.random.randn(len(sb r_a = a.subs( k ) r_b = b.subs( k ) # prove there is a difference if (r_a - r_b)**2 1e-30: # not the same? the expressions are different eq = False break return eq Absolutely. I've also implemented a similar function in one PR: https://github.com/sympy/sympy/pull/8036/files?diff=unified#diff-2c9ef1ef2c82f5d5781d0d12e1fe4910R33 It was pointed out to me that we have similar machinery here already: https://github.com/sympy/sympy/blob/master/sympy/utilities/randtest.py#L43 This should be unified and put into sympy. We can call it zero_numerical or something like that (test_numerically, ...). Mathematica calls this PossibleZeroQ (though I think it does both symbolic an numerical tests). Look at the implementation in my PR --- you should allow the user to specify the range (I call it [a, b]) as well as the precision. I think we can perhaps just test for 0, and then your equiv can just call this zero testing function for a-b. Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVCti4Rcqoe7Mo7Yz%3D4cZ5jj6gG7%2BrxvGfrjeK5SLOa4%2BA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
On Mon, Feb 9, 2015 at 12:40 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: Hi Peter, On Mon, Feb 9, 2015 at 9:09 AM, Peter Chervenski spoo...@abv.bg wrote: I made this function to test for the equivalence of two expressions. It doesn't really prove anything, but if the tests are many, the probability of it being wrong becomes negligible. Do such utility functions have a place in SymPy? def equiv(a, b, ntests=15): Test if expression a is equivalent to b by comparing the results of many random numeric tests # get the symbols sb_a = filter(lambda x: x.is_Symbol, a.atoms()) sb_b = filter(lambda x: x.is_Symbol, b.atoms()) sb = list(set(sb_a + sb_b)) eq = True for i in xrange(ntests): k = dict(zip(sb, np.random.randn(len(sb r_a = a.subs( k ) r_b = b.subs( k ) # prove there is a difference if (r_a - r_b)**2 1e-30: # not the same? the expressions are different eq = False break return eq Absolutely. I've also implemented a similar function in one PR: https://github.com/sympy/sympy/pull/8036/files?diff=unified#diff-2c9ef1ef2c82f5d5781d0d12e1fe4910R33 It was pointed out to me that we have similar machinery here already: https://github.com/sympy/sympy/blob/master/sympy/utilities/randtest.py#L43 This should be unified and put into sympy. We can call it zero_numerical or something like that (test_numerically, ...). Mathematica calls this PossibleZeroQ (though I think it does both symbolic an numerical tests). Look at the implementation in my PR --- you should allow the user to specify the range (I call it [a, b]) as well as the precision. I think we can perhaps just test for 0, and then your equiv can just call this zero testing function for a-b. Actually, in my implementation I choose random integers from [-a, a] and then test an interval [-a/b, a/b]. That way you will get rational numbers, as opposed to only integers (that could hide differences). Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVDnybsk6Ke-ocGoPd%2BuB_S7v%3DDCeSgvGTR1JFTXiw5F_g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
Doesn't expr.equals also do something similar to this? Aaron Meurer On Mon, Feb 9, 2015 at 1:42 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 12:40 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: Hi Peter, On Mon, Feb 9, 2015 at 9:09 AM, Peter Chervenski spoo...@abv.bg wrote: I made this function to test for the equivalence of two expressions. It doesn't really prove anything, but if the tests are many, the probability of it being wrong becomes negligible. Do such utility functions have a place in SymPy? def equiv(a, b, ntests=15): Test if expression a is equivalent to b by comparing the results of many random numeric tests # get the symbols sb_a = filter(lambda x: x.is_Symbol, a.atoms()) sb_b = filter(lambda x: x.is_Symbol, b.atoms()) sb = list(set(sb_a + sb_b)) eq = True for i in xrange(ntests): k = dict(zip(sb, np.random.randn(len(sb r_a = a.subs( k ) r_b = b.subs( k ) # prove there is a difference if (r_a - r_b)**2 1e-30: # not the same? the expressions are different eq = False break return eq Absolutely. I've also implemented a similar function in one PR: https://github.com/sympy/sympy/pull/8036/files?diff=unified#diff-2c9ef1ef2c82f5d5781d0d12e1fe4910R33 It was pointed out to me that we have similar machinery here already: https://github.com/sympy/sympy/blob/master/sympy/utilities/randtest.py#L43 This should be unified and put into sympy. We can call it zero_numerical or something like that (test_numerically, ...). Mathematica calls this PossibleZeroQ (though I think it does both symbolic an numerical tests). Look at the implementation in my PR --- you should allow the user to specify the range (I call it [a, b]) as well as the precision. I think we can perhaps just test for 0, and then your equiv can just call this zero testing function for a-b. Actually, in my implementation I choose random integers from [-a, a] and then test an interval [-a/b, a/b]. That way you will get rational numbers, as opposed to only integers (that could hide differences). Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVDnybsk6Ke-ocGoPd%2BuB_S7v%3DDCeSgvGTR1JFTXiw5F_g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6JV%3D_umM9hOnn446tz7Hz3bAL2g1%2B7TuqhYbdG1hmTCGg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
I'm unclear what this line is doing https://github.com/sympy/sympy/blob/e015652bf34987128bca3176d1c939fbd0d486cf/sympy/core/expr.py#L613. It looks like it evaluates it, at least in some cases. Probably Chris Smith could give a more definite answer. Aaron Meurer On Mon, Feb 9, 2015 at 5:20 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 4:15 PM, Aaron Meurer asmeu...@gmail.com wrote: On Mon, Feb 9, 2015 at 5:11 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 3:37 PM, Aaron Meurer asmeu...@gmail.com wrote: Doesn't expr.equals also do something similar to this? No, that uses symbolics (thus it is not able to check complex expressions or it will be slow). Btw, you already asked this exact question here: https://github.com/sympy/sympy/pull/8036#issuecomment-55969269 and my answer is right below it. Heh. But I seem to remember equals plugging in values. Maybe it used to do it, but doesn't any more? The code is here: https://github.com/sympy/sympy/blob/e015652bf34987128bca3176d1c939fbd0d486cf/sympy/core/expr.py#L563 Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVCB2Ftb_bAQUNnh2F%3DeHZA_Oy1dOrTn7W5ApkfATfOpsQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6LBTww%3DvNVTj6hUu6sJ0QUt%3DohbPcNo5b6bAq1rFsiiUA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
On Mon, Feb 9, 2015 at 3:37 PM, Aaron Meurer asmeu...@gmail.com wrote: Doesn't expr.equals also do something similar to this? No, that uses symbolics (thus it is not able to check complex expressions or it will be slow). Btw, you already asked this exact question here: https://github.com/sympy/sympy/pull/8036#issuecomment-55969269 and my answer is right below it. Ondrej Aaron Meurer On Mon, Feb 9, 2015 at 1:42 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 12:40 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: Hi Peter, On Mon, Feb 9, 2015 at 9:09 AM, Peter Chervenski spoo...@abv.bg wrote: I made this function to test for the equivalence of two expressions. It doesn't really prove anything, but if the tests are many, the probability of it being wrong becomes negligible. Do such utility functions have a place in SymPy? def equiv(a, b, ntests=15): Test if expression a is equivalent to b by comparing the results of many random numeric tests # get the symbols sb_a = filter(lambda x: x.is_Symbol, a.atoms()) sb_b = filter(lambda x: x.is_Symbol, b.atoms()) sb = list(set(sb_a + sb_b)) eq = True for i in xrange(ntests): k = dict(zip(sb, np.random.randn(len(sb r_a = a.subs( k ) r_b = b.subs( k ) # prove there is a difference if (r_a - r_b)**2 1e-30: # not the same? the expressions are different eq = False break return eq Absolutely. I've also implemented a similar function in one PR: https://github.com/sympy/sympy/pull/8036/files?diff=unified#diff-2c9ef1ef2c82f5d5781d0d12e1fe4910R33 It was pointed out to me that we have similar machinery here already: https://github.com/sympy/sympy/blob/master/sympy/utilities/randtest.py#L43 This should be unified and put into sympy. We can call it zero_numerical or something like that (test_numerically, ...). Mathematica calls this PossibleZeroQ (though I think it does both symbolic an numerical tests). Look at the implementation in my PR --- you should allow the user to specify the range (I call it [a, b]) as well as the precision. I think we can perhaps just test for 0, and then your equiv can just call this zero testing function for a-b. Actually, in my implementation I choose random integers from [-a, a] and then test an interval [-a/b, a/b]. That way you will get rational numbers, as opposed to only integers (that could hide differences). Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVDnybsk6Ke-ocGoPd%2BuB_S7v%3DDCeSgvGTR1JFTXiw5F_g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6JV%3D_umM9hOnn446tz7Hz3bAL2g1%2B7TuqhYbdG1hmTCGg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVBH3KHccMaR1dX4Uz4jAMzXqBXaaxGHz%3D6ZmZq0XtucTA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
On Mon, Feb 9, 2015 at 5:11 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 3:37 PM, Aaron Meurer asmeu...@gmail.com wrote: Doesn't expr.equals also do something similar to this? No, that uses symbolics (thus it is not able to check complex expressions or it will be slow). Btw, you already asked this exact question here: https://github.com/sympy/sympy/pull/8036#issuecomment-55969269 and my answer is right below it. Heh. But I seem to remember equals plugging in values. Maybe it used to do it, but doesn't any more? Aaron Meurer Ondrej Aaron Meurer On Mon, Feb 9, 2015 at 1:42 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 12:40 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: Hi Peter, On Mon, Feb 9, 2015 at 9:09 AM, Peter Chervenski spoo...@abv.bg wrote: I made this function to test for the equivalence of two expressions. It doesn't really prove anything, but if the tests are many, the probability of it being wrong becomes negligible. Do such utility functions have a place in SymPy? def equiv(a, b, ntests=15): Test if expression a is equivalent to b by comparing the results of many random numeric tests # get the symbols sb_a = filter(lambda x: x.is_Symbol, a.atoms()) sb_b = filter(lambda x: x.is_Symbol, b.atoms()) sb = list(set(sb_a + sb_b)) eq = True for i in xrange(ntests): k = dict(zip(sb, np.random.randn(len(sb r_a = a.subs( k ) r_b = b.subs( k ) # prove there is a difference if (r_a - r_b)**2 1e-30: # not the same? the expressions are different eq = False break return eq Absolutely. I've also implemented a similar function in one PR: https://github.com/sympy/sympy/pull/8036/files?diff=unified#diff-2c9ef1ef2c82f5d5781d0d12e1fe4910R33 It was pointed out to me that we have similar machinery here already: https://github.com/sympy/sympy/blob/master/sympy/utilities/randtest.py#L43 This should be unified and put into sympy. We can call it zero_numerical or something like that (test_numerically, ...). Mathematica calls this PossibleZeroQ (though I think it does both symbolic an numerical tests). Look at the implementation in my PR --- you should allow the user to specify the range (I call it [a, b]) as well as the precision. I think we can perhaps just test for 0, and then your equiv can just call this zero testing function for a-b. Actually, in my implementation I choose random integers from [-a, a] and then test an interval [-a/b, a/b]. That way you will get rational numbers, as opposed to only integers (that could hide differences). Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVDnybsk6Ke-ocGoPd%2BuB_S7v%3DDCeSgvGTR1JFTXiw5F_g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6JV%3D_umM9hOnn446tz7Hz3bAL2g1%2B7TuqhYbdG1hmTCGg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVBH3KHccMaR1dX4Uz4jAMzXqBXaaxGHz%3D6ZmZq0XtucTA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6LD_mLNEMZDC6hVi02iOBg4ex7KzrgN0Cp0hYq8bhURxg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Equivalence test
On Mon, Feb 9, 2015 at 4:15 PM, Aaron Meurer asmeu...@gmail.com wrote: On Mon, Feb 9, 2015 at 5:11 PM, Ondřej Čertík ondrej.cer...@gmail.com wrote: On Mon, Feb 9, 2015 at 3:37 PM, Aaron Meurer asmeu...@gmail.com wrote: Doesn't expr.equals also do something similar to this? No, that uses symbolics (thus it is not able to check complex expressions or it will be slow). Btw, you already asked this exact question here: https://github.com/sympy/sympy/pull/8036#issuecomment-55969269 and my answer is right below it. Heh. But I seem to remember equals plugging in values. Maybe it used to do it, but doesn't any more? The code is here: https://github.com/sympy/sympy/blob/e015652bf34987128bca3176d1c939fbd0d486cf/sympy/core/expr.py#L563 Ondrej -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVCB2Ftb_bAQUNnh2F%3DeHZA_Oy1dOrTn7W5ApkfATfOpsQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
