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  • Could not determine the size of this expression.

    - by Søren
    Hi, I have resently started to use MATLAB Simulink, and my problem is that i can't implement an AMDF function, because simulink compiler cannot determine the lengths. Simulink errors: |--------------------------------------------------------------------------------------- Could not determine the size of this expression. Function 'Embedded MATLAB Function2' (#38.728.741), line 33, column 32: "1:flength-k+1" Errors occurred during parsing of Embedded MATLAB function 'Embedded MATLAB Function2'(#38) Embedded MATLAB Interface Error: Errors occurred during parsing of Embedded MATLAB function 'Embedded MATLAB Function2'(#38) . |--------------------------------------------------------------------------------------- MY CODE: |--------------------------------------------------------------------------------------- persistent sLength persistent fLength persistent amdf % Length of the frame flength = length(frame); % Pitch period is between 2.5 ms and 19.5 ms for LPC-10 algorithm % This because this algorithm assumes the frequencyspan is 50 and 400 Hz pH = ceil((1/min(fspan))*fs); if(pH flength) pH = flength; end; pL = ceil((1/max(fspan))*fs); if(pL <= 0 || pL = flength) pL = 0; end; sLength = pH - pL; % Normalize the frame frame = frame/max(max(abs(frame))); % Allocating memory for the calculation of the amdf %amdf = zeros(1,sLength); %%%%%%%% amdf = 0; % Calculating the AMDF with unbiased normalizing for k = (pL+1):pH amdf(k-pL) = sum(abs(frame(1:flength-k+1) - frame(k:flength)))/(flength-k+1); end; % Output of the AMDF if(min(amdf) < lvlThr) voiced = 1; else voiced = 0; end; % Output of the minimum of the amdf minAMDF = min(amdf); |---------------------------------------------------------------------------------------- HELP Kind regards Søren

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  • Select highest rated, oldest track

    - by Blair McMillan
    I have several tables: CREATE TABLE [dbo].[Tracks]( [Id] [uniqueidentifier] NOT NULL, [Artist_Id] [uniqueidentifier] NOT NULL, [Album_Id] [uniqueidentifier] NOT NULL, [Title] [nvarchar](255) NOT NULL, [Length] [int] NOT NULL, CONSTRAINT [PK_Tracks_1] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] CREATE TABLE [dbo].[TrackHistory]( [Id] [int] IDENTITY(1,1) NOT NULL, [Track_Id] [uniqueidentifier] NOT NULL, [Datetime] [datetime] NOT NULL, CONSTRAINT [PK_TrackHistory] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] INSERT INTO [cooltunes].[dbo].[TrackHistory] ([Track_Id] ,[Datetime]) VALUES ("335294B0-735E-4E2C-8389-8326B17CE813" ,GETDATE()) CREATE TABLE [dbo].[Ratings]( [Id] [int] IDENTITY(1,1) NOT NULL, [Track_Id] [uniqueidentifier] NOT NULL, [User_Id] [uniqueidentifier] NOT NULL, [Rating] [tinyint] NOT NULL, CONSTRAINT [PK_Ratings] PRIMARY KEY CLUSTERED ( [Id] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] INSERT INTO [cooltunes].[dbo].[Ratings] ([Track_Id] ,[User_Id] ,[Rating]) VALUES ("335294B0-735E-4E2C-8389-8326B17CE813" ,"C7D62450-8BE6-40F6-80F1-A539DA301772" ,1) Users User_Id|Guid Other fields Links between the tables are pretty obvious. TrackHistory has each track added to it as a row whenever it is played ie. a track will appear in there many times. Ratings value will either be 1 or -1. What I'm trying to do is select the Track with the highest rating, that is more than 2 hours old, and if there is a duplicate rating for a track (ie a track receives 6 +1 ratings and 1 - rating, giving that track a total rating of 5, another track also has a total rating of 5), the track that was last played the longest ago should be returned. (If all tracks have been played within the last 2 hours, no rows should be returned) I'm getting somewhere doing each part individually using the link above, SUM(Value) and GROUP BY Track_Id, but I'm having trouble putting it all together. Hopefully someone with a bit more (MS)SQL knowledge will be able to help me. Many thanks!

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  • regex php: find everything in div

    - by Fifth-Edition
    I'm trying to find eveything inside a div using regexp. I'm aware that there probably is a smarter way to do this - but I've chosen regexp. so currently my regexp pattern looks like this: $gallery_pattern = '/([\s\S]*)<\/div/'; And it does the trick - somewhat. the problem is if i have two divs after each other - like this. <div class="gallery">text to extract here</div> <div class="gallery">text to extract from here as well</div> I want to extract the information from both divs, but my problem, when testing, is that im not getting the text in between as a result but instead: "text to extract here text to extract from here as well" So . to sum up. It skips the first end of the div. and continues on to the next. The text inside the div can contain "<", "/" and linebreaks. just so you know! Does anyone have a simple solution to this problem? Im still a regexp novice.

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  • MySQL table data transformation -- how can I dis-aggregate MySQL time data?

    - by lighthouse65
    We are coding for a MySQL data warehousing application that stores descriptive data (User ID, Work ID, Machine ID, Start and End Time columns in the first table below) associated with time and production quantity data (Output and Time columns in the first table below) upon which aggregate (SUM, COUNT, AVG) functions are applied. We now wish to dis-aggregate time data for another type of analysis. Our current data table design: +---------+---------+------------+---------------------+---------------------+--------+------+ | User ID | Work ID | Machine ID | Event Start Time | Event End Time | Output | Time | +---------+---------+------------+---------------------+---------------------+--------+------+ | 080025 | ABC123 | M01 | 2008-01-24 16:19:15 | 2008-01-24 16:34:45 | 2120 | 930 | +---------+---------+------------+---------------------+---------------------+--------+------+ Reprocessing dis-aggregation that we would like to do would be to transform table content based on a granularity of minutes, rather than the current production event ("Event Start Time" and "Event End Time") granularity. The resulting reprocessing of existing table rows would look like: +---------+---------+------------+---------------------+--------+ | User ID | Work ID | Machine ID | Production Minute | Output | +---------+---------+------------+---------------------+--------+ | 080025 | ABC123 | M01 | 2010-01-24 16:19 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:20 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:21 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:22 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:23 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:24 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:25 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:26 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:27 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:28 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:29 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:30 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:31 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:22 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:33 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:34 | 133 | +---------+---------+------------+---------------------+--------+ So the reprocessing would take an existing row of data created at the granularity of production event and modify the granularity to minutes, eliminating redundant (Event End Time, Time) columns while doing so. It assumes a constant rate of production and divides output by the difference in minutes plus one to populate the new table's Output column. I know this can be done in code...but can it be done entirely in a MySQL insert statement (or otherwise entirely in MySQL)? I am thinking of a INSERT ... INTO construction but keep getting stuck. An additional complexity is that there are hundreds of machines to include in the operation so there will be multiple rows (one for each machine) for each minute of the day. Any ideas would be much appreciated. Thanks.

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  • How to minimize total cost of shortest path tree

    - by Michael
    I have a directed acyclic graph with positive edge-weights. It has a single source and a set of targets (vertices furthest from the source). I find the shortest paths from the source to each target. Some of these paths overlap. What I want is a shortest path tree which minimizes the total sum of weights over all edges. For example, consider two of the targets. Given all edge weights equal, if they share a single shortest path for most of their length, then that is preferable to two mostly non-overlapping shortest paths (fewer edges in the tree equals lower overall cost). Another example: two paths are non-overlapping for a small part of their length, with high cost for the non-overlapping paths, but low cost for the long shared path (low combined cost). On the other hand, two paths are non-overlapping for most of their length, with low costs for the non-overlapping paths, but high cost for the short shared path (also, low combined cost). There are many combinations. I want to find solutions with the lowest overall cost, given all the shortest paths from source to target. Does this ring any bells with anyone? Can anyone point me to relevant algorithms or analogous applications? Cheers!

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  • Flex 3: should I provide prepared data to my component or make it to process data before display?

    - by grapkulec
    I'm starting to learn a little Flex just for fun and maybe to prove that I still can learn something new :) I have some idea for a project and one of its parts is a tree component which could display data in different ways depending on configuration. The idea There is list of objects having properties like id, date, time, name, description. And sometimes list should be displayed like this: first level: date second level: time third level: name and sometimes like this: first level: year second level: month third level: day fourth level: time and name By level I mean level of nesting of course. So, we can have years, that have months, that have days, that have hours and so forth. The problem What could be the best way to do it? I mean, should I prepare data for different ways of nesting outside of component or even outside of flex? I can do it at web service level in C# where I plan to have database access layer and send to flex nice and ready to display XML or array of objects. But I wonder if that won't cause additional and maybe unneccessary network traffic. I tried to hack some code in my component to convert my data objects into XML or ArrayCollection but I don't know enough of Flex and got stuck on elimination of duplicates or getting specific data by some key value. Usually to do such things I have STL with maps, sets and vectors and I find Flex arrays and even Dictionary a little bit confusing (I've read language reference and googled without any significant luck). The question So, to sum things up: should I give my tree component data prepared just for chosen type of display or should I try to do it internally inside component (or some helper class written in ActionScript)?

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  • Code golf: combining multiple sorted lists into a single sorted list

    - by Alabaster Codify
    Implement an algorithm to merge an arbitrary number of sorted lists into one sorted list. The aim is to create the smallest working programme, in whatever language you like. For example: input: ((1, 4, 7), (2, 5, 8), (3, 6, 9)) output: (1, 2, 3, 4, 5, 6, 7, 8, 9) input: ((1, 10), (), (2, 5, 6, 7)) output: (1, 2, 5, 6, 7, 10) Note: solutions which concatenate the input lists then use a language-provided sort function are not in-keeping with the spirit of golf, and will not be accepted: sorted(sum(lists,[])) # cheating: out of bounds! Apart from anything else, your algorithm should be (but doesn't have to be) a lot faster! Clearly state the language, any foibles and the character count. Only include meaningful characters in the count, but feel free to add whitespace to the code for artistic / readability purposes. To keep things tidy, suggest improvement in comments or by editing answers where appropriate, rather than creating a new answer for each "revision". EDIT: if I was submitting this question again, I would expand on the "no language provided sort" rule to be "don't concatenate all the lists then sort the result". Existing entries which do concatenate-then-sort are actually very interesting and compact, so I won't retro-actively introduce a rule they break, but feel free to work to the more restrictive spec in new submissions. Inspired by http://stackoverflow.com/questions/464342/combining-two-sorted-lists-in-python

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  • Sort and limit queryset by comment count and date using queryset.extra() (django)

    - by thornomad
    I am trying to sort/narrow a queryset of objects based on the number of comments each object has as well as by the timeframe during which the comments were posted. Am using a queryset.extra() method (using django_comments which utilizes generic foreign keys). I got the idea for using queryset.extra() (and the code) from here. This is a follow-up question to my initial question yesterday (which shows I am making some progress). Current Code: What I have so far works in that it will sort by the number of comments; however, I want to extend the functionality and also be able to pass a time frame argument (eg, 7 days) and return an ordered list of the most commented posts in that time frame. Here is what my view looks like with the basic functionality in tact: import datetime from django.contrib.comments.models import Comment from django.contrib.contenttypes.models import ContentType from django.db.models import Count, Sum from django.views.generic.list_detail import object_list def custom_object_list(request, queryset, *args, **kwargs): '''Extending the list_detail.object_list to allow some sorting. Example: http://example.com/video?sort_by=comments&days=7 Would get a list of the videos sorted by most comments in the last seven days. ''' try: # this is where I started working on the date business ... days = int(request.GET.get('days', None)) period = datetime.datetime.utcnow() - datetime.timedelta(days=int(days)) except (ValueError, TypeError): days = None period = None sort_by = request.GET.get('sort_by', None) ctype = ContentType.objects.get_for_model(queryset.model) if sort_by == 'comments': queryset = queryset.extra(select={ 'count' : """ SELECT COUNT(*) AS comment_count FROM django_comments WHERE content_type_id=%s AND object_pk=%s.%s """ % ( ctype.pk, queryset.model._meta.db_table, queryset.model._meta.pk.name ), }, order_by=['-count']).order_by('-count', '-created') return object_list(request, queryset, *args, **kwargs) What I've Tried: I am not well versed in SQL but I did try just to add another WHERE criteria by hand to see if I could make some progress: SELECT COUNT(*) AS comment_count FROM django_comments WHERE content_type_id=%s AND object_pk=%s.%s AND submit_date='2010-05-01 12:00:00' But that didn't do anything except mess around with my sort order. Any ideas on how I can add this extra layer of functionality? Thanks for any help or insight.

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  • Where is my python script spending time? Is there "missing time" in my cprofile / pstats trace?

    - by fmark
    I am attempting to profile a long running python script. The script does some spatial analysis on raster GIS data set using the gdal module. The script currently uses three files, the main script which loops over the raster pixels called find_pixel_pairs.py, a simple cache in lrucache.py and some misc classes in utils.py. I have profiled the code on a moderate sized dataset. pstats returns: p.sort_stats('cumulative').print_stats(20) Thu May 6 19:16:50 2010 phes.profile 355483738 function calls in 11644.421 CPU seconds Ordered by: cumulative time List reduced from 86 to 20 due to restriction <20> ncalls tottime percall cumtime percall filename:lineno(function) 1 0.008 0.008 11644.421 11644.421 <string>:1(<module>) 1 11064.926 11064.926 11644.413 11644.413 find_pixel_pairs.py:49(phes) 340135349 544.143 0.000 572.481 0.000 utils.py:173(extent_iterator) 8831020 18.492 0.000 18.492 0.000 {range} 231922 3.414 0.000 8.128 0.000 utils.py:152(get_block_in_bands) 142739 1.303 0.000 4.173 0.000 utils.py:97(search_extent_rect) 745181 1.936 0.000 2.500 0.000 find_pixel_pairs.py:40(is_no_data) 285478 1.801 0.000 2.271 0.000 utils.py:98(intify) 231922 1.198 0.000 2.013 0.000 utils.py:116(block_to_pixel_extent) 695766 1.990 0.000 1.990 0.000 lrucache.py:42(get) 1213166 1.265 0.000 1.265 0.000 {min} 1031737 1.034 0.000 1.034 0.000 {isinstance} 142740 0.563 0.000 0.909 0.000 utils.py:122(find_block_extent) 463844 0.611 0.000 0.611 0.000 utils.py:112(block_to_pixel_coord) 745274 0.565 0.000 0.565 0.000 {method 'append' of 'list' objects} 285478 0.346 0.000 0.346 0.000 {max} 285480 0.346 0.000 0.346 0.000 utils.py:109(pixel_coord_to_block_coord) 324 0.002 0.000 0.188 0.001 utils.py:27(__init__) 324 0.016 0.000 0.186 0.001 gdal.py:848(ReadAsArray) 1 0.000 0.000 0.160 0.160 utils.py:50(__init__) The top two calls contain the main loop - the entire analyis. The remaining calls sum to less than 625 of the 11644 seconds. Where are the remaining 11,000 seconds spent? Is it all within the main loop of find_pixel_pairs.py? If so, can I find out which lines of code are taking most of the time?

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  • Examples of monoids/semigroups in programming

    - by jkff
    It is well-known that monoids are stunningly ubiquitous in programing. They are so ubiquitous and so useful that I, as a 'hobby project', am working on a system that is completely based on their properties (distributed data aggregation). To make the system useful I need useful monoids :) I already know of these: Numeric or matrix sum Numeric or matrix product Minimum or maximum under a total order with a top or bottom element (more generally, join or meet in a bounded lattice, or even more generally, product or coproduct in a category) Set union Map union where conflicting values are joined using a monoid Intersection of subsets of a finite set (or just set intersection if we speak about semigroups) Intersection of maps with a bounded key domain (same here) Merge of sorted sequences, perhaps with joining key-equal values in a different monoid/semigroup Bounded merge of sorted lists (same as above, but we take the top N of the result) Cartesian product of two monoids or semigroups List concatenation Endomorphism composition. Now, let us define a quasi-property of an operation as a property that holds up to an equivalence relation. For example, list concatenation is quasi-commutative if we consider lists of equal length or with identical contents up to permutation to be equivalent. Here are some quasi-monoids and quasi-commutative monoids and semigroups: Any (a+b = a or b, if we consider all elements of the carrier set to be equivalent) Any satisfying predicate (a+b = the one of a and b that is non-null and satisfies some predicate P, if none does then null; if we consider all elements satisfying P equivalent) Bounded mixture of random samples (xs+ys = a random sample of size N from the concatenation of xs and ys; if we consider any two samples with the same distribution as the whole dataset to be equivalent) Bounded mixture of weighted random samples Which others do exist?

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  • How can I work around SQL Server - Inline Table Value Function execution plan variation based on par

    - by Ovidiu Pacurar
    Here is the situation: I have a table value function with a datetime parameter ,lest's say tdf(p_date) , that filters about two million rows selecting those with column date smaller than p_date and computes some aggregate values on other columns. It works great but if p_date is a custom scalar value function (returning the end of day in my case) the execution plan is altered an the query goes from 1 sec to 1 minute execution time. A proof of concept table - 1K products, 2M rows: CREATE TABLE [dbo].[POC]( [Date] [datetime] NOT NULL, [idProduct] [int] NOT NULL, [Quantity] [int] NOT NULL ) ON [PRIMARY] The inline table value function: CREATE FUNCTION tdf (@p_date datetime) RETURNS TABLE AS RETURN ( SELECT idProduct, SUM(Quantity) AS TotalQuantity, max(Date) as LastDate FROM POC WHERE (Date < @p_date) GROUP BY idProduct ) The scalar value function: CREATE FUNCTION [dbo].[EndOfDay] (@date datetime) RETURNS datetime AS BEGIN DECLARE @res datetime SET @res=dateadd(second, -1, dateadd(day, 1, dateadd(ms, -datepart(ms, @date), dateadd(ss, -datepart(ss, @date), dateadd(mi,- datepart(mi,@date), dateadd(hh, -datepart(hh, @date), @date)))))) RETURN @res END Query 1 - Working great SELECT * FROM [dbo].[tdf] (getdate()) The end of execution plan: Stream Aggregate Cost 13% <--- Clustered Index Scan Cost 86% Query 2 - Not so great SELECT * FROM [dbo].[tdf] (dbo.EndOfDay(getdate())) The end of execution plan: Stream Aggregate Cost 4% <--- Filter Cost 12% <--- Clustered Index Scan Cost 86%

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  • Implementing custom Matlab functions in Simulink

    - by niko
    Hi, I would like to use custom Matlab function in Simulink. So far I have done it by placing Embedded Matlab Fuction block. However if the custom function contains another custom function the compile process fails. Here is the example of function I am trying to embed in the simulation: function [c, d, iterationsCount] = decodeLDPC(y, H, variance) Lci = initializeLq(y, H, variance); Lr = getLr(Lci); [Lq, c] = getLq(Lci, H, Lr); iterationsCount = 1; while(sum(mod(c * H', 2)) ~= 0) Lr = getLr(Lq); [Lq, c] = getLq(Lq, H, Lr); iterationsCount = iterationsCount + 1; end; G = getGeneratorMatrix(H); d = c/G; where initializeLq and getLr are custom functions as well. I would be very thankful if anyone could suggest a method to implement the above function in the simulation. Thank you.

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  • SQL: Need help with query construction.

    - by Geeknidas
    Hi Guys, I am relatively new with sql and I need some help with some basic query construction. Problem: To retrieve the number of orders and the customer id from a table based on a set of parameters. I want to write a query to figure out the number of orders under each customer (Column: Customerid) along with the CustomerID where the number of orders should be greater or equal to 10 and the status of the order should be Active. Moreover, I also want to know the first transaction date of an order belonging to each customerid. Table Description: product_orders Orderid CustomerId Transaction_date Status ------- ---------- ---------------- ------- 1 23 2-2-10 Active 2 22 2-3-10 Active 3 23 2-3-10 Deleted 4 23 2-3-10 Active Query that I have written: select count(*), customerid from product_orders where status = 'Active' GROUP BY customerid ORDER BY customerid; The above statement gives me the sum of all order under a customer id but does not fulfil the condition of atleast 10 orders. I donot know how to display the first transaction date along with the order under a customerid (status: could be active or delelted doesn't matter) Ideal solutions should look like: Total Orders CustomerID Transaction Date (the first transaction date) ------------ ---------- ---------------- 11 23 1-2-10 Thanks in advance. I hope you guys would be kind enough to stop by and help me out. Cheers, Leonidas

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  • Precision error on matrix multiplication

    - by Wam
    Hello all, Coding a matrix multiplication in my program, I get precision errors (inaccurate results for large matrices). Here's my code. The current object has data stored in a flattened array, row after row. Other matrix B has data stored in a flattened array, column after column (so I can use pointer arithmetic). protected double[,] multiply (IMatrix B) { int columns = B.columns; int rows = Rows; int size = Columns; double[,] result = new double[rows,columns]; for (int row = 0; row < rows; row++) { for (int col = 0; col < columns; col++) { unsafe { fixed (float* ptrThis = data) fixed (float* ptrB = B.Data) { float* mePtr = ptrThis + row*rows; float* bPtr = ptrB + col*columns; double value = 0.0; for (int i = 0; i < size; i++) { value += *(mePtr++) * *(bPtr++); } result[row, col] = value; } } } } } Actually, the code is a bit more complicated : I do the multiply thing for several chunks (so instead of having i from 0 to size, I go from localStart to localStop), then sum up the resulting matrices. My problem : for a big matrix I get precision error : NUnit.Framework.AssertionException: Error at (0,1) expected: <6.4209571409444209E+18> but was: <6.4207619776304906E+18> Any idea ?

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  • Microsoft Solver Foundation constraint

    - by emaster70
    Hello, I'm trying to use Microsoft Solver Foundation 2 to solve a fairly complicated situation, however I'm stuck with an UnsupportedModelException even when I dumb down the model as much as possible. Does anyone have an idea of what I'm doing wrong? Following is the least example required to reproduce the problematic behavior. var ctx = SolverContext.GetContext(); var model = ctx.CreateModel(); var someConstant = 1337.0; var decisionA = new Decision(Domain.Real, "decisionA"); var decisionB = new Decision(Domain.Real, "decisionB"); var decisionC = new Decision(Domain.Real, "decisionC"); model.AddConstraint("ca", decisionA <= someConstant); model.AddConstraint("cb", decisionB <= someConstant); model.AddConstraint("cc", decisionC <= someConstant); model.AddConstraint("mainConstraint", Model.Equal(Model.Sum(decisionA, decisionB, decisionC), someConstant)) model.AddGoal("myComplicatedGoal", GoalKind.Minimize, decisionC); var solution = ctx.Solve(); solution.GetReport().WriteTo(Console.Out); Console.ReadKey(); Please consider that my actual model should include, once complete, a few constraints in the form of a*a+b*a <= someValue, so if what I'm willing to do ultimately isn't supported, please let me know in advance. If that's the case I'd also appreciate a suggestion of some other solver with a .NET friendly interface that I could use (only well-known commercial packages, please). Thanks in advance

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  • Divide a path into N sections using Java or PostgreSQL/PostGIS

    - by Guido
    Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

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  • Matlab Simulation: Point (symbol) Moving from start point to end point and back

    - by niko
    Hi, I would like to create an animation to demonstrate LDPC coding which is based on Sum-Product Algorithm So far I have created a graph which shows the connections between symbol nodes (left) and parity nodes (right) and would like to animate points travelling from symbol to parity nodes and back. The figure is drawn by executing the following method: function drawVertices(H) hold on; nodesCount = size(H); parityNodesCount = nodesCount(1); symbolNodesCount = nodesCount(2); symbolPoints = zeros(symbolNodesCount, 2); symbolPoints(:, 1) = 0; for i = 0 : symbolNodesCount - 1 ji = symbolNodesCount - i; scatter(0, ji) symbolPoints(i + 1, 2) = ji; end; parityPoints = zeros(parityNodesCount, 2); parityPoints(:, 1) = 10; for i = 0 : parityNodesCount - 1 ji = parityNodesCount - i; y0 = symbolNodesCount/2 - parityNodesCount/2; scatter(10, y0 + ji) parityPoints(i + 1, 2) = y0 + ji; end; axis([-1 11 -1 symbolNodesCount + 2]); axis off %connect vertices d = size(H); for i = 1 : d(1) for j = 1 : d(2) if(H(i, j) == 1) plot([parityPoints(i, 1) symbolPoints(j, 1)], [parityPoints(i, 2) symbolPoints(j, 2)]); end; end; end; So what I would like to do here is to add another method which takes start point (x and y) and end point as arguments and animates a travelling circle (dot) from start to end and back along the displayed lines. I would appreciate if anyone of you could show the solution or suggest any useful tutorial about matlab simulations. Thank you!

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  • SQL Query: How to determine "Seen during N hour" if given two DateTime time stamps?

    - by efess
    Hello all. I'm writing a statistics application based off a SQLite database. There is a table which records when users Login and Logout (SessionStart, SessionEnd DateTimes). What i'm looking for is a query that can show what hours user have been logged in, in sort of a line graph way- so between the hours of 12:00 and 1:00AM there were 60 users logged in (at any point), between the hours of 1:00 and 2:00AM there were 54 users logged in, etc... And I want to be able to run a SUM of this, which is why I can't bring the records into .NET and iterate through them that way. I've come up with a rather primative approach, a subquery for each hour of the day, however this approach has proved to be slow and slow. I need to be able to calculate this for a couple hundred thousand records in a split second.. SELECT case when (strftime('%s',datetime(date(sessionstart), '+0 hours')) > strftime('%s',sessionstart) AND strftime('%s',datetime(date(sessionstart), '+0 hours')) < strftime('%s',sessionend)) OR (strftime('%s',datetime(date(sessionstart), '+1 hours')) > strftime('%s',sessionstart) AND strftime('%s',datetime(date(sessionstart), '+1 hours')) < strftime('%s',sessionend)) OR (strftime('%s',datetime(date(sessionstart), '+0 hours')) < strftime('%s',sessionstart) AND strftime('%s',datetime(date(sessionstart), '+1 hours')) > strftime('%s',sessionend)) then 1 else 0 end as hour_zero, ... hour_one, ... hour_two, ........ hour_twentythree FROM UserSession I'm wondering what better way to determine if two DateTimes have been seen durring a particular hour (best case scenario, how many times it has crossed an hour if it was logged in multiple days, but not necessary)? The only other idea I had is have a "hour" table specific to this, and just tally up the hours the user has been seen at runtime, but I feel like this is more of a hack than the previous SQL. Any help would be greatly appreciated!

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  • Mysql - What's wrong with the query...?

    - by SpikETidE
    Hi everybody.... I am trying to query a database to find the following If a customer searches for a hotel in a city between dates A and B, find and return the hotels in which rooms are free between the two dates. There will be more than one room in each room type(i.e. 5 Rooms in type A, 10 rooms in Type B etc) and we have to query the db to find only those hotels in which there is atleast one room free in atleast one type. This is my table structure.... **Structure for table 'reservations'** reservation_id hotel_id room_id customer_id payment_id no_of_rooms check_in_date check_out_date reservation_date **Structure for table 'hotels'** hotel_id hotel_name hotel_description hotel_address hotel_location hotel_country hotel_city hotel_type hotel_stars hotel_image hotel_deleted **Structure for table 'rooms'** room_id hotel_id room_name max_persons total_rooms room_price room_image agent_commision room_facilities service_tax vat city_tax room_description room_deleted And this is my query $city_search = '15'; $check_in_date = '29-03-2010'; $check_out_date = '31-03-2010'; $dateFormat_check_in = "DATE_FORMAT('$reservations.check_in_date','%d-%m-%Y')"; $dateFormat_check_out = "DATE_FORMAT('$reservations.check_out_date','%d-%m-%Y')"; $dateCheck = "$dateFormat_check_in >= '$check_in_date' AND $dateFormat_check_out <= '$check_out_date'"; $query = "SELECT $rooms.room_id, $rooms.room_name, $rooms.max_persons, $rooms.room_price, $hotels.hotel_id, $hotels.hotel_name, $hotels.hotel_stars, $hotels.hotel_type FROM $hotels,$rooms,$reservations WHERE $hotels.hotel_city = '$city_search' AND $hotels.hotel_id = $rooms.hotel_id AND $hotels.hotel_deleted = '0' AND $rooms.room_deleted = '0' AND $rooms.total_rooms - (SELECT SUM($reservations.no_of_rooms) as tot FROM $reservations WHERE $dateCheck GROUP BY $reservations.room_id) > '0'"; The number of rooms already reserved in each room type in each hotel will be stored in the reservations table... The thing is the query doesn't return any result at all...even though it should if i calculate it myself manually... I tried running the sub-query alone and i don't get any result... And i have lost quite some amount of hair trying to de-bug this query from yesterday... What's wrong with this...? Or is there a better way to do what i mentioned above...? Thanks for your time... Edit : Code edited to remove an bud... thanks to

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  • SQL Is it possible to setup a column that will contain a value dependent on another column?

    - by Wesley
    I have a table (A) that lists all bundles created off a machine in a day. It lists the date created and the weight of the bundle. I have an ID column, a date column, and a weight column. I also have a table (B) that holds the details related to that machine for the day. In that table (B), I want a column that lists a sum of weights from the other table (A) that the dates match on. So if the machine runs 30 bundles in a day, I'll have 30 rows in table (A) all dated the same day. In table (B) I'll have 1 row detailing other information about the machine for the day plus the column that holds the total bundle weight created for the day. Is there a way to make the total column in table (B) automatically adjust itself whenever a row is added to table (A)? Is this possible to do in the table schema itself rather than in an SQL statement each time a bundle is added? If it's not, what sort of SQL statement do I need? Wes

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  • Calculate an Internet (aka IP, aka RFC791) checksum in C#

    - by Pat
    Interestingly, I can find implementations for the Internet Checksum in almost every language except C#. Does anyone have an implementation to share? Remember, the internet protocol specifies that: "The checksum field is the 16 bit one's complement of the one's complement sum of all 16 bit words in the header. For purposes of computing the checksum, the value of the checksum field is zero." More explanation can be found from Dr. Math. There are some efficiency pointers available, but that's not really a large concern for me at this point. Please include your tests! (Edit: Valid comment regarding testing someone else's code - but I am going off of the protocol and don't have test vectors of my own and would rather unit test it than put into production to see if it matches what is currently being used! ;-) Edit: Here are some unit tests that I came up with. They test an extension method which iterates through the entire byte collection. Please comment if you find fault in the tests. [TestMethod()] public void InternetChecksum_SimplestValidValue_ShouldMatch() { IEnumerable<byte> value = new byte[1]; // should work for any-length array of zeros ushort expected = 0xFFFF; ushort actual = value.InternetChecksum(); Assert.AreEqual(expected, actual); } [TestMethod()] public void InternetChecksum_ValidSingleByteExtreme_ShouldMatch() { IEnumerable<byte> value = new byte[]{0xFF}; ushort expected = 0xFF; ushort actual = value.InternetChecksum(); Assert.AreEqual(expected, actual); } [TestMethod()] public void InternetChecksum_ValidMultiByteExtrema_ShouldMatch() { IEnumerable<byte> value = new byte[] { 0x00, 0xFF }; ushort expected = 0xFF00; ushort actual = value.InternetChecksum(); Assert.AreEqual(expected, actual); }

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  • Creating a Hello World library function in assembly and calling it from C#

    - by Filip Ekberg
    Let's say we use NASM as they do in this answer: how to write hellow world in assembly under windows. I got a couple of thoughts and questions regarding assembly combined with c# or any other .net languages for that matter. First of all I want to be able to create a library that has the following function HelloWorld that takes this parameter: Name In C# the method signature would looke like this: void HelloWorld(string name) and it would print out something like Hello World from name I've searched around a bit but can't find that much good and clean material for this to get me started. I know some basic assembly from before mostly gasthough. So any pointers in the right direction is very much apprechiated. To sum it up Create a function in ASM ( NASM ) that takes one or more parameters Compile and create a library of the above functionality Include the library in any .net language Call the included library function Bonus features How does one handle returned values? Is it possible to write the ASM-method inline? When creating libraries in assembly or c, you do follow a certain "pre defined" way, the c calling convetion, correct?

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  • Linq: Why won't Group By work when Querying DataSets?

    - by jrcs3
    While playing with Linq Group By statements using both DataSet and Linq-to-Sql DataContext, I get different results with the following VB.NET 10 code: #If IS_DS = True Then Dim myData = VbDataUtil.getOrdersDS #Else Dim myData = VbDataUtil.GetNwDataContext #End If Dim MyList = From o In myData.Orders Join od In myData.Order_Details On o.OrderID Equals od.OrderID Join e In myData.Employees On o.EmployeeID Equals e.EmployeeID Group By FullOrder = New With { .OrderId = od.OrderID, .EmployeeName = (e.FirstName & " " & e.LastName), .ShipCountry = o.ShipCountry, .OrderDate = o.OrderDate } _ Into Amount = Sum(od.Quantity * od.UnitPrice) Where FullOrder.ShipCountry = "Venezuela" Order By FullOrder.OrderId Select FullOrder.OrderId, FullOrder.OrderDate, FullOrder.EmployeeName, Amount For Each x In MyList Console.WriteLine( String.Format( "{0}; {1:d}; {2}: {3:c}", x.OrderId, x.OrderDate, x.EmployeeName, x.Amount)) Next With Linq2SQL, the grouping works properly, however, the DataSet code doesn't group properly. Here are the functions that I call to create the DataSet and Linq-to-Sql DataContext Public Shared Function getOrdersDS() As NorthwindDS Dim ds As New NorthwindDS Dim ota As New OrdersTableAdapter ota.Fill(ds.Orders) Dim otda As New Order_DetailsTableAdapter otda.Fill(ds.Order_Details) Dim eda As New EmployeesTableAdapter eda.Fill(ds.Employees) Return ds End Function Public Shared Function GetNwDataContext() As NorthwindL2SDataContext Dim s As New My.MySettings Return New NorthwindL2SDataContext(s.NorthwindConnectionString) End Function What am I missing? If it should work, how do I make it work, if it can't work, why not (what interface isn't implemented, etc)?

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  • Magi squares, recursive

    - by user310827
    Hi, my problem is, I'm trying to permute all posibilities for 3x3 square and check if the combination is magic. I've added a tweak with (n%3==0) if statement that if the sum of numbers in row differs from 15 it breaks the creation of other two lines... but it doesn't work, any suggestions, I call the function with Permute(1). public static class Global { //int[] j = new int[6]; public static int[] a= {0,0,0,0,0,0,0,0,0}; public static int[] b= {0,0,0,0,0,0,0,0,0}; public static int count = 0; } public static void Permute(int n) { int tmp=n-1; for (int i=0;i<9;i++){ if (Global.b[i]==0 ) { Global.b[i]=1; Global.a[n-1]=i+1; if ((n % 3) == 0) { if (Global.a[0+tmp]+Global.a[1+tmp]+Global.a[2+tmp] == 15) { if (n<9) { Permute(n+1); } else { isMagic(Global.a); } } else break; } else { Permute(n+1); } Global.b[i]=0; } } }

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  • How do I model teams and gameplay in this scorekeeping application?

    - by Eric Hill
    I'm writing a scorekeeping application for card game that has a few possibly-interesting constraints. The application accepts user registrations for players, then lets them check-in to a particular game (modeled as Event). After the final player registers, the app should generate teams, singles or doubles, depending on the preference of the person running the game and some validations (can't do doubles if there's an odd number checked in). There are @event.teams.count rounds in the game. To sum up: An event consists of `@event.teams.count` rounds; Teams can have 1 or more players Events have n or n/2 teams (depending on whether it's singles or doubles) Users will be members of different teams at different events Currently I have a rat's nest of associations: class User < ActiveRecord::Base has_many :teams, :through => :players has_many :events, :through => :teams class Event < ActiveRecord::Base has_many :rounds has_many :teams has_many :players, :through => :teams class Player < ActiveRecord::Base belongs_to :user belongs_to :team end class Team < ActiveRecord::Base has_many :players belongs_to :event end class Round < ActiveRecord::Base belongs_to :event belongs_to :user end The sticky part is team generation. I have basically a "start game" button that should freeze the registrations and pair up teams either singly or doubly, and render to Round#new so that the first (and subsequent) matches can be scored. Currently I'm implementing this as a check on Round#new that calls Event#generate_teams and displays the view: # Event#generate_teams def generate_teams # User has_many :events, :through => :registrations # self.doubles is a boolean denoting 2 players per team registrations.in_groups_of(self.doubles ? 2 : 1, nil).each do |side| self.teams << Player.create(self,side) end end Which doesn't work. Should there maybe be a Game model that ties everything together rather than (my current method) defining the game as an abstraction via the relationships between Events, Users, and Rounds (and Teams and Players and etc.)? My head is swimming.

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