I have a couple problems with this “answer”, which roughly replace the transcendental function calls (which are indeed bijections) with symbols and solving for these symbols.
The most serious is that the transformed expressions are rational functions, and he proposed solution solves for their numerators. The author failed to note that for each proposed solution, the denominators are zero, meaning that the expressions are undefined at these points. Using those propôsed solutions require serious justifications (e. g. computing the limits of the (transformed) expressions at these points). See my answer <https://github.com/sympy/sympy/issues/24824#issuecomment-1474975520>. Le mardi 7 mars 2023 à 04:18:07 UTC+1, [email protected] a écrit : > An answer is given in https://github.com/sympy/sympy/issues/24824 > > On Sunday, March 5, 2023 at 1:26:50 PM UTC-6 [email protected] wrote: > >> I think you should simplifythe equation and reduce the computational >> complexity as much as possible. It may also be helpful to check the >> implementation for errors or potential issues with the input parameters. >> >> On Tuesday, 28 February 2023 at 21:35:24 UTC+5:30 [email protected] >> wrote: >> >>> Hi all, >>> I try to solve a non linear equation but it conitnue runiing since 48 >>> hours now. >>> `` >>> import sympy as sp >>> >>> X = sp.MatrixSymbol('X',2,2) >>> W = sp.MatrixSymbol('W',2,2) >>> Y = sp.MatrixSymbol('Y',1,2) >>> W_X = sp.MatMul(W,X.T) >>> >>> liste = [] >>> for i in range(W_X.shape[0]): >>> row = [] >>> for j in range(W_X.shape[1]): >>> row.append(1/(1+sp.exp(-W_X[i,j]))) >>> >>> liste.append(row) >>> sigmoid = sp.Matrix(liste) >>> >>> liste = [] >>> for i in range(Y.shape[0]): >>> row = [] >>> for j in range(Y.shape[1]): >>> row.append(sp.log(Y[i,j]/(1-Y[i,j]))) >>> liste.append(row) >>> log_Y = sp.Matrix(liste) >>> >>> test = sigmoid.inv() >>> >>> W2 = sp.MatMul(log_Y,test).as_explicit() >>> >>> liste = [] >>> for index in range(W2.shape[1]): >>> for i in range(W.shape[0]): >>> for j in range(W.shape[1]): >>> liste.append(W2[index].diff(W[i,j])) >>> >>> >>> p = sp.solve(liste,list(W),check=False,manual=True) >>> ``` >>> >>> >>> Do someone have an idea where i am wrong or if it is from sympy ? >>> >>> Thanks a lot >>> >> -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/f35f8cf2-37af-4930-a544-0e2c04ec56e6n%40googlegroups.com.
