AttributeError: 'CString' object has no attribute 'decode'  Scouring the internet doesn't find me much. AFAIK it seems to be part of Cython. Anyone who can point me in the right direction? Im also not getting much of a stack trace. (Inherited a fairly large django project)
I have embedded a Python interpreter in a C program.  Suppose the C program reads some bytes from a file into a char array and learns (somehow) that the bytes represent text with a certain encoding (e.g., ISO 8859-1, Windows-1252, or UTF-8).  How do I decode the contents of this char array into a Python string?  The Python string should in general be of type unicode—for instance, a 0x93 in Windows-1252 encoded input becomes a u'\u0201c'.  I have attempted to use PyString_Decode, but it always fails when there are non-ASCII characters in the string.  Here is an example that fails:  #include &lt;Python.h&gt; #include &lt;stdio.h&gt;  int main(int argc, char *argv[]) {      char c_string[] = { (char)0x93, 0 };      PyObject *py_string;       Py_Initialize();       py_string = PyString_Decode(c_string, 1, "windows_1252", "replace");      if (!py_string) {           PyErr_Print();           return 1;      }      return 0; }   The error message is UnicodeEncodeError: 'ascii' codec can't encode character u'\u201c' in position 0: ordinal not in range(128), which indicates that the ascii encoding is used even though we specify windows_1252 in the call to PyString_Decode.  The following code works around the problem by using PyString_FromString to create a Python string of the undecoded bytes, then calling its decode method:  #include &lt;Python.h&gt; #include &lt;stdio.h&gt;  int main(int argc, char *argv[]) {      char c_string[] = { (char)0x93, 0 };      PyObject *raw, *decoded;       Py_Initialize();       raw = PyString_FromString(c_string);      printf("Undecoded: ");      PyObject_Print(raw, stdout, 0);      printf("\n");      decoded = PyObject_CallMethod(raw, "decode", "s", "windows_1252");      Py_DECREF(raw);      printf("Decoded: ");      PyObject_Print(decoded, stdout, 0);      printf("\n");      return 0; }
Maximum and minimum value of Determinant of $3 \times 3$ Matrix with entries $\pm 1$ Find Maximum value of Determinant of $3 \times 3$ Matrix  with  entries $\pm 1$  My try:  I considered a matrix as :  $$A=\begin{bmatrix} 1 &amp;-1  &amp;-1 \\  -1 &amp;1  &amp;-1 \\   -1&amp;-1  &amp;1  \end{bmatrix}$$  we have $$Det(A)=-4$$ and maximum is $4$, but how can we show that these are max and min values?   I also tried as follows:  By definition Determinant of a matrix is dot product of elements of any row with corresponding Cofactors  hence  $$Det(A)=a_{11}C_{11}+a_{12}C_{12}+a_{13}C_{13}$$  By cauchy Scwartz Inequality we have  $$a_{11}C_{11}+a_{12}C_{12}+a_{13}C_{13} \le \left(\sqrt{a_{11}^2+a_{12}^2+a_{13}^2}\right)\left(\sqrt{C_{11}^2+C_{12}^2+C_{13}^2}\right)$$  any way to proceed here? Subdomain versus subdirectory A 398MB directory was only compressed to 393MB using 7Z and Normal ZIP compression. Is this normal? If so, why do people continue to use ZIP on Windows? Which computer science / programming Stack Exchange sites do I post on? How to flash a BIOS when only a Windows binary is provided? In statistical learning, implicitly or explicitly, one always assumes that the training set $\mathcal{D} = \{ \bf {X}, \bf{y} \}$ is composed of $N$ input/response tuples $({\bf{X}}_i,y_i)$ that are independently drawn from the same joint distribution $\mathbb{P}({\bf{X}},y)$ with  $$ p({\bf{X}},y) = p( y \vert {\bf{X}}) p({\bf{X}}) $$  and $p( y \vert {\bf{X}})$ the relationship we are trying to capture through a particular learning algorithm. Mathematically, this i.i.d. assumption writes:  \begin{gather} ({\bf{X}}_i,y_i) \sim \mathbb{P}({\bf{X}},y), \forall i=1,...,N \\ ({\bf{X}}_i,y_i) \text{ independent of } ({\bf{X}}_j,y_j), \forall i \ne j \in \{1,...,N\} \end{gather}  I think we can all agree that this assumption is rarely satisfied in practice, see this related  and the wise comments of @Glen_b and @Luca.  My question is therefore:      Where exactly does the i.i.d. assumption becomes critical in practice?    [Context]   I'm asking this because I can think of many situations where such a stringent assumption is not needed to train a certain model (e.g. linear regression methods), or at least one can work around the i.i.d. assumption and obtain robust results. Actually the results will usually stay the same, it is rather the inferences that one can draw that will change (e.g. heteroskedasticity and autocorrelation consistent HAC estimators in linear regression: the idea is to re-use the good old OLS regression weights but to adapt the finite-sample behaviour of the OLS estimator to account for the violation of the Gauss-Markov assumptions).   My guess is therefore that the i.i.d. assumption is required not to be able to train a particular learning algorithm, but rather to guarantee that techniques such as cross-validation can indeed be used to infer a reliable measure of the model's capability of generalising well, which is the only thing we are interested in at the end of the day in statistical learning because it shows that we can indeed learn from the data. Intuitively, I can indeed understand that using cross-validation on dependent data could be optimistically biased (as illustrated/explained in ).   For me i.i.d. has thus nothing to do with training a particular model but everything to do with that model's generalisability. This seems to agree with a paper I found by Huan Xu et al, see "Robustness and Generalizability for Markovian Samples" .   Would you agree with that?  [Example]   If this can help the discussion, consider the problem of using the LASSO algorithm to perform a smart selection amongst $P$ features given $N$ training samples $({\bf{X}}_i,y_i)$ with $\forall i=1,...,N$ $$ {\bf{X}}_i=[X_{i1},...,X_{iP}] $$ We can further assume that:   The inputs ${\bf{X}}_i$ are dependent hence leading to a violation of the i.i.d. assumption (e.g. for each feature $j=1,..,P$ we observe a $N$ point time series, hence introducing temporal auto-correlation) The conditional responses $y_i \vert {\bf{X}}_i$ are independent. We have $P \gg N$.    In what way(s) does the violation of the i.i.d. assumption can pose problem in that case assuming we plan to determine the LASSO penalisation coefficient $\lambda$ using a cross-validation approach (on the full data set) + use a nested cross-validation to get a feel for the generalisation error of this learning strategy (we can leave the discussion concerning the inherent pros/cons of the LASSO aside, except if it is useful). An epimorphism from $S_{4}$ to $S_{3}$ having the kernel isomorphic to Klein four-group Exercise $7$, page 51 from Hungerford's book Algebra.     Show that $N=\{(1),(12)(34), (13)(24),(14)(23)\}$ is a normal subgroup   of $S_{4}$ contained in $A_{4}$ such that $S_{4}/N\cong S_{3}$ and   $A_{4}/N\cong \mathbb{Z}_{3}$.   I solved the question after many calculations. I would like to know if is possible to define an epimorphism $\varphi$ from $S_{4}$ to $S_{3}$ such that $N=\ker(\varphi)$.  Thanks for your kindly help. Bachelor thesis or Bachelor's thesis I'm trying to include Arabic text in an English document (I'm a new latex user), but I can't seem to get any Arabic text to render at all, using xelatex or any kind of tex. I'm using texshop 3.51 on a mac. I can't get this basic example to work, it just displays question marks in the output pdf.  \documentclass[12pt]{article} \usepackage[utf]{arabxetex} \newfontfamily\arabicfont[Script=Arabic]{Amiri} \begin{document} \begin{arab}[voc] وَهَذِهِ فِقرَةٌ بِالعَرَبِيَة مَعَ كَلِمَة اِنكلِيزِيَة \end{arab} \end{document}     I've downloaded Amiri (and also Scheherazade and Lateef) into Fontbook, and they show up if I go Source->Font->Show Fonts in texshop. If I remove the Amiri part it still doesn't work.   Is there anything I can do? I've looked at other links here, like  and  but I can't even render any of those examples.   Thank you so much for any help! I'll love you forever if I can get this to work. cant install or remove anything on 18.04 cause of DPKG error Is it possible to add multiple materials to a text object? I know that for a mesh you can go into edit mode and select vertices and assign a specific material to them quite easily. I want to know if it is possible to do this with a Text object (which has no vertices). I have some problems with this exercise. I don't know if it can be done. Consider the polynomial $ x^n - a \in \mathbb{Q} $ Can I compute the Galois group of this over $\mathbb{Q}$? Maybe having a nice "basis.  The splitting field is given by $\mathbb{Q}(\zeta_n,\alpha)$ , where $\zeta_n$ is a primitive root of unity , and $\alpha$ is some number such that $\alpha^n = a $. Well first of all, I want a $\underline{"good basis"}$ for the splitting field. In the sense that the minimal polynomials, of the adjoined elements, are different (in this case the computation of the galois group is very simple).  For example one easy case, it's when $a&gt;0$, then $(a)^{\frac{1}{n}} \in \mathbb{R}$ , so clearly the minimal polynomial of $(a)^{\frac{1}{n}} , \zeta_n$ are distincs, and I'm done. If $n$ is odd then , it's also easy, since one root it's also real, for example $x^3-3 $, the real root is $ \root 3 \of { - 3}  =  - \root 3 \of 3  $ , so I can consider the splitting field as $\mathbb{Q}(-\root 3 \of 3 , \zeta_3 )=\mathbb{Q}(\root 3 \of 3 , \zeta_3 )$. The difficult case is when $n$ is even and $a&lt;0$ , for example  $x^8+20$ or $x^4+20$ in some cases as in the second, there are particular cases since there exist algorithms for the Galois group of quartics, but in general. It can be done?  $\underline{Remark}$ I'm searching a $\underline{"good basis"}$ for the splitting field. In the sense that the minimal polynomials, of the adjoined elements, are different since in this case the computation of the galois group is very simple. Let me use the following example to explain my question: public string ExampleFunction(string Variable) {     return something; }  string WhatIsMyName = &quot;Hello World&quot;; string Hello = ExampleFunction(WhatIsMyName);  When I pass the variable WhatIsMyName to the ExampleFunction, I want to be able to get a string of the original variable's name. Perhaps something like: Variable.OriginalName.ToString()  Is there any way to do this? How do I pass parameter TO a Visualforce page from a link in an email? Here's what I am trying to do:  1) User creates record A.  2) Time-based workflow sends an email to the Record A creator based on a date field in the record.  3) The email template has a URL link.  4) The URL links to a Visualforce page that is basically a form with fields to be filled out (this Visualforce page is in a managed package) and a save button that creates a new User record.  5) When the User clicks the URL link in the email, the Visualforce page opens in a new window.  6) I would like to pass the values of the fields in record A to pre-fill the Visualforce page fields.   Here's my link:  &lt;a href="https://cs19.visual.force.com/apex/CloneThisUser?Desktop=true&amp;Id={!Pending_User__c.User_to_CloneId__c}&amp;formGroupInputSmall={!Pending_User__c.First_Name__c}   And here's the code from the relevant section of the Visualforce page:  &lt;div class="form-group form-group-sm"&gt;       &lt;!-- &lt;apex:outputLabel styleClass="col-sm-2 control-label" for="formGroupInputSmall"&gt;First Name&lt;/apex:outputLabel&gt; --&gt;       &lt;div class="col-xm-11 col-sm-12"&gt;           &lt;apex:inputField html-placeholder="First Name" styleClass="form-control FirstNameInput"  value="{!u.FirstName}" id="formGroupInputSmall"/&gt;       &lt;/div&gt;     &lt;/div&gt;   I have only included the first field I would like to pass the parameter to, in order to keep this post simple.   The link passes the User_to_Clone_Id__c just fine but does not fill in the "First Name" field with the value of the First_Name__c .  What am I doing incorrectly? Thanks. bi-directional sync with rsync Does $\int_{0}^{\infty}\frac{dx}{1+(x\sin5x)^2}$ converge? Display error message if same record exist with combination of some fields? I have taken three fields from case object called AccountName, IntegrationTo__c and SfType__c (checkbox).  I have created one case record with a specific combination of three fields.  For the second time I create a record with that combination, then  display error message only if SfType__c is true in first record otherwise allow  for record creation.  trigger AvoidDuplicate on Case(before insert)  {          set&lt;string&gt; newNameSet = new set&lt;string&gt;();     newNameSet = new set&lt;string&gt;();      set&lt;string&gt; newEmailSet = new set&lt;string&gt;();      set&lt;string&gt; dbNameSet = new set&lt;string&gt;();      set&lt;string&gt; dbEmailSet = new set&lt;string&gt;();      for(Case newLead : trigger.new){          newNameSet.add(newLead.Account.Name);          newEmailSet.add(newLead.IntegrationTo__c);      }      for(Case dbLead : [select id, Case.Account.Name, IntegrationTo__c from Case where IntegrationTo__c IN: newEmailSet OR Case.Account.Name IN: newNameSet]){          dbNameSet.add(dbLead.Account.Name);          dbEmailSet.add(dbLead.IntegrationTo__c);      }      for(Case newLead : trigger.new){          if(dbNameSet.contains(newLead.Account.Name) &amp;&amp; dbEmailSet.Contains(newLead.IntegrationTo__c))              newLead.addError('You are inserting Duplicate Case');      }  }   i wrote this this not checking the account field name and integration__c values only with combination of account and integration__c shows error I read about the new fancy progress bar which was added to apt 1.0 in  and how to enable it . However on running sudo apt-get update, I did not see the fancy progress bars. On reading the second link again, the solution explicitly requires you to use sudo apt update.  Hence my question is the difference between apt and apt-get. I thought they were one and the same. Can one of Newton's Laws of motion be derived from other Newton's Laws of motion? Can one derive Newton's  second and third laws from the first law or   first and third laws from the second law or  first and second  laws from the third  law  I think Newton's laws of motions are independent to each other. They can not be derived from one another. Please share the idea. What statistical test can I use to compare two ratios from two independent samples. The ratios are after to before results. I need to compare the after/before ratios for two independent models and show whether they are have significant difference or not. Please help!