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  • how to solve a weired swig python c++ interfacing type error

    - by user2981648
    I want to use swig to switch a simple cpp function to python and use "scipy.integrate.quadrature" function to calculate the integration. But python 2.7 reports a type error. Do you guys know what is going on here? Thanks a lot. Furthermore, "scipy.integrate.quad" runs smoothly. So is there something special for "scipy.integrate.quadrature" function? The code is in the following: File "testfunctions.h": #ifndef TESTFUNCTIONS_H #define TESTFUNCTIONS_H double test_square(double x); #endif File "testfunctions.cpp": #include "testfunctions.h" double test_square(double x) { return x * x; } File "swig_test.i" : /* File : swig_test.i */ %module swig_test %{ #include "testfunctions.h" %} /* Let's just grab the original header file here */ %include "testfunctions.h" File "test.py": import scipy.integrate import _swig_test print scipy.integrate.quadrature(_swig_test.test_square, 0., 1.) error info: UMD has deleted: _swig_test Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\Python27\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 523, in runfile execfile(filename, namespace) File "D:\data\haitaliu\Desktop\Projects\swig_test\Release\test.py", line 4, in <module> print scipy.integrate.quadrature(_swig_test.test_square, 0., 1.) File "C:\Python27\lib\site-packages\scipy\integrate\quadrature.py", line 161, in quadrature newval = fixed_quad(vfunc, a, b, (), n)[0] File "C:\Python27\lib\site-packages\scipy\integrate\quadrature.py", line 61, in fixed_quad return (b-a)/2.0*sum(w*func(y,*args),0), None File "C:\Python27\lib\site-packages\scipy\integrate\quadrature.py", line 90, in vfunc return func(x, *args) TypeError: in method 'test_square', argument 1 of type 'double'

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  • Can knowing C actually hurt the code you write in higher level languages?

    - by Jurily
    The question seems settled, beaten to death even. Smart people have said smart things on the subject. To be a really good programmer, you need to know C. Or do you? I was enlightened twice this week. The first one made me realize that my assumptions don't go further than my knowledge behind them, and given the complexity of software running on my machine, that's almost non-existent. But what really drove it home was this Slashdot comment: The end result is that I notice the many naive ways in which traditional C "bare metal" programmers assume that higher level languages are implemented. They make bad "optimization" decisions in projects they influence, because they have no idea how a compiler works or how different a good runtime system may be from the naive macro-assembler model they understand. Then it hit me: C is just one more abstraction, like all others. Even the CPU itself is only an abstraction! I've just never seen it break, because I don't have the tools to measure it. I'm confused. Has my mind been mutilated beyond recovery, like Dijkstra said about BASIC? Am I living in a constant state of premature optimization? Is there hope for me, now that I realized I know nothing about anything? Is there anything to know, even? And why is it so fascinating, that everything I've written in the last five years might have been fundamentally wrong? To sum it up: is there any value in knowing more than the API docs tell me? EDIT: Made CW. Of course this also means now you must post examples of the interpreter/runtime optimizing better than we do :)

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  • Int - number too large. How to get program to fail?

    - by Dave
    Hi Problem: How do you get a program to fail if a number goes beyond the bounds of its type? This code below gives the wrong answer for sum of primes under 2 million as I'd used an int instead of a long. [TestMethod] public void CalculateTheSumOfPrimesBelow2million() { int result = PrimeTester.calculateTheSumOfPrimesBelow(2000000); // 2million Assert.AreEqual(1, result); // 1,179,908,154 .. this was what I got with an int... // correct answer was 142,913,828,922 with a long } public static class PrimeTester { public static int calculateTheSumOfPrimesBelow(int maxPrimeBelow) { // we know 2 is a prime number int sumOfPrimes = 2; int currentNumberBeingTested = 3; while (currentNumberBeingTested < maxPrimeBelow) { double squareRootOfNumberBeingTested = (double)Math.Sqrt(currentNumberBeingTested); bool isPrime = true; for (int i = 2; i <= squareRootOfNumberBeingTested; i++) { if (currentNumberBeingTested % i == 0) { isPrime = false; break; } } if (isPrime) sumOfPrimes += currentNumberBeingTested; currentNumberBeingTested += 2; // as we don't want to test even numbers } return sumOfPrimes; } }

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  • How to sort data in a table data structure in Java?

    - by rgksugan
    I need to sort data based on the third column of the table data structure. I tried based on the answers for the following question. But my sorting does not work. Please help me in this. Here goes my code. Object[] data = new Object[y]; rst.beforeFirst(); while (rst.next()) { int p_id = Integer.parseInt(rst.getString(1)); String sw2 = "select sum(quantity) from tbl_order_detail where product_id=" + p_id; rst1 = stmt1.executeQuery(sw2); rst1.next(); String sw3 = "select max(order_date) from tbl_order where tbl_order.`Order_ID` in (select tbl_order_detail.`Order_ID` from tbl_order_detail where product_id=" + p_id + ")"; rst2 = stmt2.executeQuery(sw3); rst2.next(); data[i] = new Object[]{new String(rst.getString(2)), new String(rst.getString(3)), new Integer(rst1.getString(1)), new String(rst2.getString(1))}; i++; } ColumnComparator cc = new ColumnComparator(2); Arrays.sort(data, cc); if (i == 0) { table.addCell(""); table.addCell(""); table.addCell(""); table.addCell(""); } else { for (int j = 0; j < y; j++) { Object[] theRow = (Object[]) data[j]; table.addCell((String) theRow[0]); table.addCell((String) theRow[1]); table.addCell((String) theRow[2]); table.addCell((String) theRow[3]); }

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  • Building an array out of values from another array

    - by George
    This is a follow up from a question of mine that was just answered concerning parsing numbers in an array. I have an array, data[], with numbers that I'd like to use in a calculation and then put the resulting values into another array. So say data[0] = 100. I'd like to find a percentage using the calculatin, (data[0]/dataSum*100).toFixed(2) where dataSum is the sum of all the numbers in data[]. I've tried: dataPercentage = []; for (var i=0; i < data.length; i++) { data[i] = parseFloat(data[i]); dataSum += data[i]; // looping through data[i] and setting it equal to dataPercentage. dataPercentage[] = (data[i]/dataSum*100).toFixed(2); // thought maybe I was overriding dataPercentage everytime I looped? dataPercentage[] += (data[i]/dataSum*100).toFixed(2); } I also tried just setting dataPercentage = [(data/dataSum*100).toFixed(2)], but I think this creates a nested array, which I don't think is what I need.

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  • SQL Server 2008 Prior String Extract

    - by Saidur Rahman
    I have strings like the ones below in a SQL column. I want to extract them as a Gigabyte amount in aggregate. Example: Original Column ---------> Expected Output from a TSQL function ------------------------------------------- $15 / 1GB 24m + Intern 120MB ----------> 1.12 GB $19.95 / 500MB + $49.95 / 9GB Blackberry -----> 9.5GB $174.95 Blackberry 24GB + $10 / 1GB Datapack ----> 25GB $79 / 6GB --> 6GB Null --> Null $20 Plan --> 0GB Note: for our purpose, 1000MB = 1 GB (not 1024). The pattern is numbers followed by GB/MB, usually they are combined like 1GB (without any space but may sometimes may contain a space, it is not particularly important if hard to implement for this exception). Sometimes there are up to three or four instances of GB/MB occurring in the same string which are usually separated by a + sign (see row 2 and 3 of my example above). I have seen how we extract the dollar values in one of the answers where numbers were followed by $ or extract all integers in a string but I don't want to extract the dollar values or all the integers in a string. I just want the sum of GB/MB in the string.

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  • How can I identify an element from a list within another list

    - by Alex
    I have been trying to make a block of code that finds the index of the largest bid for each item. Then I was going to use the index as a way to identify the person who paid that much moneys name. However no matter what i try I can't link the person and what they have gained from the auction together. Here is the code I have been writing: It has to be able to work with any information inputted def sealedBids(): n = int(input('\nHow many people are in the group? ')) z = 0 g = [] s = [] b = [] f = [] w = []#goes by number of items q = [] while z < n: b.append([]) z = z + 1 z = 0 while z < n: g.append(input('Enter a bidders name: ')) z = z + 1 z = 0 i = int(input('How many items are being bid on?')) while z < i: s.append(input('Enter the name of an item: ')) w.append(z) z = z + 1 z = 0 for j in range(n):#specifies which persons bids your taking for k in range(i):#specifies which item is being bid on b[j].append(int(input('How much money has {0} bid on the {1}? '.format(g[j], s[k])))) print(' ') for j in range(n):#calculates fair share f.append(sum(b[j])/n) for j in range(i):#identifies which quantity of money was the largest for each item for k in range(n): if w[j] < b[k][j]: w[j] = b[k][j] q.append(k) any advice is much appreciated.

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  • PHP custom function code optimization

    - by Alex
    Now comes the hard part. How do you optimize this function: function coin_matrix($test, $revs) { $coin = array(); for ($i = 0; $i < count($test); $i++) { foreach ($revs as $j => $rev) { foreach ($revs as $k => $rev) { if ($j != $k && $test[$i][$j] != null && $test[$i][$k] != null) { if(!isset($coin[$test[$i][$j]])) { $coin[$test[$i][$j]] = array(); } if(!isset($coin[$test[$i][$j]][$test[$i][$k]])) { $coin[$test[$i][$j]][$test[$i][$k]] = 0; } $coin[$test[$i][$j]][$test[$i][$k]] += 1 / ($some_var - 1); } } } } return $coin; } I'm not that good at this and if the arrays are large, it runs forever. The function is supposed to find all pairs of values from a two-dim array and sum them like this: $coin[$i][$j] += sum_of_pairs_in_array_row / [count(elements_of_row) - 1] Thanks a lot!

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  • Very simple python functions takes spends long time in function and not subfunctions

    - by John Salvatier
    I have spent many hours trying to figure what is going on here. The function 'grad_logp' in the code below is called many times in my program, and cProfile and runsnakerun the visualize the results reveals that the function grad_logp spends about .00004s 'locally' every call not in any functions it calls and the function 'n' spends about .00006s locally every call. Together these two times make up about 30% of program time that I care about. It doesn't seem like this is function overhead as other python functions spend far less time 'locally' and merging 'grad_logp' and 'n' does not make my program faster, but the operations that these two functions do seem rather trivial. Does anyone have any suggestions on what might be happening? Have I done something obviously inefficient? Am I misunderstanding how cProfile works? def grad_logp(self, variable, calculation_set ): p = params(self.p,self.parents) return self.n(variable, self.p) def n (self, variable, p ): gradient = self.gg(variable, p) return np.reshape(gradient, np.shape(variable.value)) def gg(self, variable, p): if variable is self: gradient = self._grad_logps['x']( x = self.value, **p) else: gradient = __builtin__.sum([self._pgradient(variable, parameter, value, p) for parameter, value in self.parents.iteritems()]) return gradient

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  • Python: Removing particular character (u"\u2610") from string

    - by duhaime
    I have been wrestling with decoding and encoding in Python, and I can't quite figure out how to resolve my problem. I am looping over xml text files (sample) that are apparently coded in utf-8, using Beautiful Soup to parse each file, then looking to see if any sentence in the file contains one or more words from two different list of words. Because the xml files are from the eighteenth century, I need to retain the em dashes that are in the xml. The code below does this just fine, but it also retains a pesky box character that I wish to remove. I believe the box character is this character. (You can find an example of the character I wish to remove in line 3682 of the sample file above. On this webpage, the character looks like an 'or' pipe, but when I read the xml file in Komodo, it looks like a box. When I try to copy and paste the box into a search engine, it looks like an 'or' pipe. When I print to console, though, the character looks like an empty box.) To sum up, the code below runs without errors, but it prints the empty box character that I would like to remove. for work in glob.glob(pathtofiles): openfile = open(work) readfile = openfile.read() stringfile = str(readfile) decodefile = stringfile.decode('utf-8', 'strict') #is this the dodgy line? soup = BeautifulSoup(decodefile) textwithtags = soup.findAll('text') textwithtagsasstring = str(textwithtags) #this method strips everything between anglebrackets as it should textwithouttags = stripTags(textwithtagsasstring) #clean text nonewlines = textwithouttags.replace("\n", " ") noextrawhitespace = re.sub(' +',' ', nonewlines) print noextrawhitespace #the boxes appear I tried to remove the boxes by using noboxes = noextrawhitespace.replace(u"\u2610", "") But Python threw an error flag: UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 280: ordinal not in range(128) Does anyone know how I can remove the boxes from the xml files? I would be grateful for any help others can offer.

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  • Counting character count in Access database column ins SQL

    - by jzr
    Good Evening. My problem is possibly very easy, I just have spent some time researching now and probably have a brain lock and unable to solve this, help would be much appreciated. database structure: col1 col2 col3 col4 ==================== 1233+4566+ABCD+CDEF 1233+4566+ACD1+CDEF 1233+4566+D1AF+CDEF I need to count character count in col3, wanted result in from the previous table would be: char count =========== A 3 B 1 C 2 D 3 F 1 1 2 is this possible to achieve by using SQL only? at the moment I am thinking of passing a parameter in to SQL query and count the characters one by one and then sum, however I did not start the VBA part yet, and frankly wouldn't want to do that. this is my query at the moment: PARAMETERS X Long; SELECT First(Mid(TABLE.col3,X,1)) AS [col3 Field], Count(Mid(TABLE.col3,X,1)) AS Dcount FROM TEST GROUP BY Mid(TABLE.col3,X,1) HAVING (((Count(Mid([TABLE].[col3],[X],1)))>=1)); ideas and help are much appreciated, as being said this is probably very for some of your guys, I don't usually work with access and SQL. Thanks.

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  • Replace duplicate values in array with new randomly generated values

    - by RussellDias
    I have below a function (created by Gordon in a previous question that went unanswered) that creates an array with n amount of values. The sum of the array is equal to $max. function randomDistinctPartition($n, $max) { $partition= array(); for($i=1; $i < $n; $i++) { $maxSingleNumber = $max - $n; $partition[] = $number = rand(1, $maxSingleNumber); } $max -= $number; } $partition[] = $max; return $partition; } For example: If I set $n = 4 and $max = 30. Then I should get the following. array(5, 7, 10, 8); However, this function does not take into account duplicates and 0s. What I would like - and have been trying to accomplish - is to generate an array with unique numbers that add up to my predetermined variable $max. No Duplicate numbers and No 0 and/or negative integers.

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  • Deleting unneeded rows from a table with 2 criteria

    - by stormbreaker
    Hello. I have a many-to-many relations table and I need to DELETE the unneeded rows. The lastviews table's structure is: | user (int) | document (int) | time (datetime) | This table logs the last users which viewed the document. (user, document) is unique. I show only the last 10 views of a document and until now I deleted the unneeded like this: DELETE FROM `lastviews` WHERE `document` = ? AND `user` NOT IN (SELECT * FROM (SELECT `user` FROM `lastviews` WHERE `document` = ? ORDER BY `time` DESC LIMIT 10) AS TAB) However, now I need to also show the last 5 documents a user has viewed. This means I can no longer delete rows using the previous query because it might delete information I need (say a user didn't view documents in 5 minutes and the rows are deleted) To sum up, I need to delete all the records that don't fit these 2 criterias: SELECT ... FROM `lastviews` WHERE `document` = ? ORDER BY `time` DESC LIMIT 10 and SELECT * FROM `lastviews` WHERE `user` = ? ORDER BY `time` DESC LIMIT 0, 5 I need the logic. Thanks in advance.

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  • How to clean up my code

    - by simion
    Being new to this i realy am trying to learn how to keep code as simple as possible, whilst doing the job its supposed to. The question i have done is from project eulur, it says Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ... Find the sum of all the even-valued terms in the sequence which do not exceed four million. Here is my code below, i was wondering what the best way of simplifying this would be, for a start removing all of the .get(list.length()-1 )..... stuff would be a good start if possible but i dont really no how to? Thanks public long fibb() { ArrayList<Integer> list = new ArrayList<Integer>(); list.add(1); list.add(2); while((list.get(list.size() - 1) + (list.get(list.size() - 2)) < 4000000)){ list.add((list.get(list.size()-1)) + (list.get(list.size() - 2))); } long value = 0; for(int i = 0; i < list.size(); i++){ if(list.get(i) % 2 == 0){ value += list.get(i); } } return value; }

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  • PHP - advice for java HashMap alternative in php?

    - by teutara
    I know it is super noob and will be answered in no time, but I could not figure.. sorry for any inconvenience.. Here is the thing: ID colA colB Length 1 seq1 seq11 1 2 seq1 seq11 11 3 seq3 seq33 21 4 seq3 seq33 14 I have a db with this kind of a table, has more than 10M rows. I want to loop though colA first, get the relevant colB value, and check if there are any other occurrences of the same value. For example in colB (seq11) there are 2 occurrences of colA(seq1), this time I have to combine those and output the sum of the length. Similar to this: ID colA colB Length 1 seq1 seq11 12 2 seq3 seq33 35 I am a bit java guy, but because my colleague has written everything in php and this will be just an adding, i need a php solution. With java i would have used hashmap, so that I would have the colA data once and just increment the value of "Length Column".. I know it is not a proper question, but.. Thank you in advance.. $$$$$$$$$$ EDIT $$$$$$$$$$ I tried this query in order to group by occurences: SELECT COUNT(*) SeqName FROM SeqTable GROUP BY SeqName HAVING COUNT(*)>0;

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  • Passing C++ object to C++ code through Python?

    - by cornail
    Hi all, I have written some physics simulation code in C++ and parsing the input text files is a bottleneck of it. As one of the input parameters, the user has to specify a math function which will be evaluated many times at run-time. The C++ code has some pre-defined function classes for this (they are actually quite complex on the math side) and some limited parsing capability but I am not satisfied with this construction at all. What I need is that both the algorithm and the function evaluation remain speedy, so it is advantageous to keep them both as compiled code (and preferrably, the math functions as C++ function objects). However I thought of glueing the whole simulation together with Python: the user could specify the input parameters in a Python script, while also implementing storage, visualization of the results (matplotlib) and GUI, too, in Python. I know that most of the time, exposing C++ classes can be done, e.g. with SWIG but I still have a question concerning the parsing of the user defined math function in Python: Is it possible to somehow to construct a C++ function object in Python and pass it to the C++ algorithm? E.g. when I call f = WrappedCPPGaussianFunctionClass(sigma=0.5) WrappedCPPAlgorithm(f) in Python, it would return a pointer to a C++ object which would then be passed to a C++ routine requiring such a pointer, or something similar... (don't ask me about memory management in this case, though :S) The point is that no callback should be made to Python code in the algorithm. Later I would like to extend this example to also do some simple expression parsing on the Python side, such as sum or product of functions, and return some compound, parse-tree like C++ object but let's stay at the basics for now. Sorry for the long post and thx for the suggestions in advance.

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  • How to make cycle over cycles in Java?

    - by Roman
    I would like to make a cycle over the following elements: [1,2,11,12,21,22,111,112,121,122,....,222222] or for example [1,2,3,11,12,13,21,22,23,31,32,33,111,112,113,... 333333333] How can I make it in Java? In my particular case I use 4 digits (1,2,3,4) and the length of the last number can be from 1 to 10. I managed to do it in Python and PHP. In the first case I used list over lists. I started from [[1],[2],] then for every element of the list I added 1 and 2, so I got [[1,1],[1,2],[2,1],[2,2]] and so on: nchips = sum(chips) traj = [[]] last = [[]] while len(last[0]) < nchips: newlast = [] for tr in last: for d in [1,2,3,4]: newlast.append(tr + [d]) last = newlast traj += last When I did it in PHP I used number with base 3. But it was a tricky and non elegant solution. for ($i=-1; $i<=$n; $i+=1) { if ($i>-1) { $n5 = base_convert($i,10,5); $n5_str = strval($n5); $tr = array(); $found = 0; for ($j=0; $j<strlen($n5_str); $j+=1) { $k = $n5_str[$j]; if ($k==0) { $found = 1; break; } array_push($tr,$k); } if ($found==1) continue; } else { $tr = array(); } } Can it be done easily in Java?

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  • Effective simulation of compound poisson process in Matlab

    - by Henrik
    I need to simulate a huge bunch of compound poisson processes in Matlab on a very fine grid so I am looking to do it most effectively. I need to do a lot of simulations on the same random numbers but with parameters changing so it is practical to draw the uniforms and normals beforehand even though it means i have to draw a lot more than i will probably need and won't matter much because it will only need to be done once compared to in the order 500*n repl times the actual compound process generation. My method is the following: Let T be for how long i need to simulate and N the grid points, then my grid is: t=linspace(1,T,N); Let nrepl be the number of processes i need then I simulate P=poissrnd(lambda,nrepl,1); % Number of jumps for each replication U=(T-1)*rand(10000,nrepl)+1; % Set of uniforms on (1,T) for jump times N=randn(10000,nrepl); % Set of normals for jump size Then for replication j: Poiss=P(j); % Jumps for replication Uni=U(1:Poiss,j);% Jump times Norm=mu+sigma*N(1:Poiss,j);% Jump sizes Then this I guess is where I need your advice, I use this one-liner but it seems very slow: CPP_norm=sum(bsxfun(@times,bsxfun(@gt,t,Uni),Norm),1); In the inner for each jump it creates a series of same length as t with 0 until jump and then 1 after, multiplying this will create a grid with zeroes until jump has arrived and then the jump size and finally adding all these will produce the entire jump process on the grid. How can this be done more effectively? Thank you very much.

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  • How does Haskell do pattern matching without us defining an Eq on our data types?

    - by devoured elysium
    I have defined a binary tree: data Tree = Null | Node Tree Int Tree and have implemented a function that'll yield the sum of the values of all its nodes: sumOfValues :: Tree -> Int sumOfValues Null = 0 sumOfValues (Node Null v Null) = v sumOfValues (Node Null v t2) = v + (sumOfValues t2) sumOfValues (Node t1 v Null) = v + (sumOfValues t1) sumOfValues (Node t1 v t2) = v + (sumOfValues t1) + (sumOfValues t2) It works as expected. I had the idea of also trying to implement it using guards: sumOfValues2 :: Tree -> Int sumOfValues2 Null = 0 sumOfValues2 (Node t1 v t2) | t1 == Null && t2 == Null = v | t1 == Null = v + (sumOfValues2 t2) | t2 == Null = v + (sumOfValues2 t1) | otherwise = v + (sumOfValues2 t1) + (sumOfValues2 t2) but this one doesn't work because I haven't implemented Eq, I believe: No instance for (Eq Tree) arising from a use of `==' at zzz3.hs:13:3-12 Possible fix: add an instance declaration for (Eq Tree) In the first argument of `(&&)', namely `t1 == Null' In the expression: t1 == Null && t2 == Null In a stmt of a pattern guard for the definition of `sumOfValues2': t1 == Null && t2 == Null The question that has to be made, then, is how can Haskell make pattern matching without knowing when a passed argument matches, without resorting to Eq?

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  • Quality questionnaire php mysql graphipcs

    - by Marcelo
    Hi, i'm making a questionnaire about a service quality, its contains the options (poor, regular, good, very good). It's contains 6 questions (radio button) and a suggestion box (textbox). In the table of the database i created 6 rows for questions, 1 for suggestion and 1 for date (a friend of mine tole me to use this but i didn't get why). q1) I'm going to atribute a value form 1 to 4 to the radio buttons options, and i'd like to sum every answer for each question, and then divide by the numbers of user that answered that question and give the mean. how am i supposed to to that? I'd also like generate reports of the month, of the year. q2) not only about the questionnaire but for registration too. I need all the fields to be completed, no blank options, if he don't complete all of fields it'll not be submitted and there will be a warning message to the user. q3) about the field type, i'd like it to be the same class that is in the database, i'm having a "problem". Ex: Name(varchar) : 1234(int), in the field 'name' of the table of the database 1234 will be shown as name, and i don't want this, i want only the type that i declared in the construction of the table. q4) i'd also like to know if it's possible to create pizza graphics, about the percentage of each question, is this possible? q5) I'm using phpmyadmin and some of my id's are auto_increment, but 'cause of my tests they at a high number, i'd like to restart to 0 the ids number, is this possible? Thanks for the attention.

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  • Generating all possible subsets of a given QuerySet in Django

    - by Glen
    This is just an example, but given the following model: class Foo(models.model): bar = models.IntegerField() def __str__(self): return str(self.bar) def __unicode__(self): return str(self.bar) And the following QuerySet object: foobar = Foo.objects.filter(bar__lt=20).distinct() (meaning, a set of unique Foo models with bar <= 20), how can I generate all possible subsets of foobar? Ideally, I'd like to further limit the subsets so that, for each subset x of foobar, the sum of all f.bar in x (where f is a model of type Foo) is between some maximum and minimum value. So, for example, given the following instance of foobar: >> print foobar [<Foo: 5>, <Foo: 10>, <Foo: 15>] And min=5, max=25, I'd like to build an object (preferably a QuerySet, but possibly a list) that looks like this: [[<Foo: 5>], [<Foo: 10>], [<Foo: 15>], [<Foo: 5>, <Foo: 10>], [<Foo: 5>, <Foo: 15>], [<Foo: 10>, <Foo: 15>]] I've experimented with itertools but it doesn't seem particularly well-suited to my needs. I think this could be accomplished with a complex QuerySet but I'm not sure how to start.

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  • Pass Arguments to Included Module in Ruby?

    - by viatropos
    I'm hoping to implement something like all of the great plugins out there for ruby, so that you can do this: acts_as_commentable has_attached_file :avatar But I have one constraint: That helper method can only include a module; it can't define any variables or methods. The reason for this is because, I want the options hash to define something like type, and that could be converted into one of say 20 different 'workhorse' modules, all of which I could sum up in a line like this: def dynamic_method(options = {}) include ("My::Helpers::#{options[:type].to_s.camelize}").constantize(options) end Then those 'workhorses' would handle the options, doing things like: has_many "#{options[:something]}" Here's what the structure looks like, and I'm wondering if you know the missing piece in the puzzle: # 1 - The workhorse, encapsuling all dynamic variables module My::Module def self.included(base) base.extend ClassMethods base.class_eval do include InstanceMethods end end module InstanceMethods self.instance_eval %Q? def #{options[:my_method]} "world!" end ? end module ClassMethods end end # 2 - all this does is define that helper method module HelperModule def self.included(base) base.extend(ClassMethods) end module ClassMethods def dynamic_method(options = {}) # don't know how to get options through! include My::Module(options) end end end # 3 - send it to active_record ActiveRecord::Base.send(:include, HelperModule) # 4 - what it looks like class TestClass < ActiveRecord::Base dynamic_method :my_method => "hello" end puts TestClass.new.hello #=> "world!" That %Q? I'm not totally sure how to use, but I'm basically just wanting to somehow be able to pass the options hash from that helper method into the workhorse module. Is that possible? That way, the workhorse module could define all sorts of functionality, but I could name the variables whatever I wanted at runtime.

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  • How i can fix the increasing order summation code?

    - by user2971559
    I want from the java to reads all numbers from the user as long as the number entered by user is bigger than the previous number. But i could write it for only positive numbers. How i can fix code below if all numbers included. If it is possible please write the solution for beginners because its my first year in computer science in college and I haven't learn a lot yet. import acm.program.*; public class IncreasingOrder extends ConsoleProgram { public void run() { int previousNumber = 0; int total = 0; int count = 0; while(true) { int n = readInt("Enter > "); if (n <= previousNumber) break; total += n; count++; previousNumber = n; } println("You have entered " + count + " numbers in increasing order."); println("Sum of these " + count + " numbers is " + total + "."); } }

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  • suggestions on syntax to express mathematical formula concisely

    - by aaa
    hello. I am developing functional domain specific embedded language within C++ to translate formulas into working code as concisely and accurately as possible. I post prototype in the comment, it is about 2 hundred lines long. Right now my language looks something like this (well, actually is going to look like): // implies two nested loops j=0:N, i=0,j (range(i) < j < N)[T(i,j) = (T(i,j) - T(j,i))/e(i+j)]; // implies summation over above expression sum(range(i) < j < N))[(T(i,j) - T(j,i))/e(i+j)]; I am looking for possible syntax improvements/extensions or just different ideas about expressing mathematical formulas as clearly and precisely as possible (in any language, not just C++). Can you give me some syntax examples relating to my question which can be accomplished in your language of choice which consider useful. In particular, if you have some ideas about how to translate the above code segments, I would be happy to hear them. Thank you just to clarify and give actual formula, my short-term goal is to express the following expression concisely where values in <> are already computed as 4-dimensional array

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  • Show menu when view is long pressed

    - by swift1691
    I've been looking around on the internet regarding my question but I couldn't find a straight answer. Is it possible to create a non-blocking menu similar to the overflow menu found in Android 4.0+ when a view is long pressed? I have a number of LinearLayout instances which have an OnLongClickListener which brings up a context menu, but it's not exactly what I am looking for. I was hoping for a smoother menu which is brought up when one of these instances is clicked, and removed when the user clicks outside of the menu's region. This is very similar to the way the overflow menu behaves in the Android ActionBar. So to sum up, is it possible to replicate the look-and-fell and the behavior of the overflow menu when using context menus? Here's hoping I don't have to jump through hoops to get the implementation that I desire. Thanks in advance. EDIT: After some digging I've found the PopupMenu which is exactly what I was looking for however it works only on devices running Honeycomb and above. Does anyone know of a way with which I can replicate this menu behavior in older versions of Android without using blocking windows like dialogs?

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