Is there a way to obtain the order of an ODE in mathematica.

For example, if i have `y''+5y`

i want mathematica return `2`

(beacuse it's a 2nd order equation). So, is it possible what i'm asking?

Is there a way to obtain the order of an ODE in mathematica.

For example, if i have `y''+5y`

i want mathematica return `2`

(beacuse it's a 2nd order equation). So, is it possible what i'm asking?

here is a way to extract the value automatically:

```
ode = y'' + y' + y == 0 ;
Max[Cases[ ode , Derivative[n_][y] :> n , Infinity]]
```

2

note this just finds the largest derivative in the expression, it doesn't verify if the expression is actually an ode..

@products = Product.order("count(votes) DESC") If you have not votes column then use: @products = Product.all.sort { |a, b| b.votes.count <=> a.votes.count } ...

So here is it mostly working, the part I don't understand is how you determine the duplicate, as when you set $fruit[2]='bag'; and then set $fruit[2]='crunchy'; it will actually be overwritten so it will be as if $fruit[2]='bag'; was never executed to begin with sample code $header[0]= 'apple'; $header[1]='banana'; $header[3]='grape';...

The output formatting needs to be mapped over the results. Export["mathematica1.dat", Transpose[{ Map[OutputForm[NumberForm[#, {3, 1}]] &, nwwa], Map[OutputForm[NumberForm[#, 6]] &, nkka]}], "Table"]; ...

The straight forward solution in this specific case is to use sortBy on the tuples, modified on the fly to "invert" the first and second elements so that in the end the ordering is reversed: val a = Array((false, 8, "zz"), (false,3, "bb"), (true, 5, "cc"),(false, 3,"dd")) a.sortBy{ case (x,y,z)...

You can try lapply lapply(spmtcars, function(x) x[order(-x$mpg),]) ...

python,wolfram-mathematica,sage

According to Trac 16703, this problem should be fixed in the latest Sage. I don't personally have a copy of Mathematica to test this on.

sql,postgresql,order,condition

Use CASE expression in ORDER BY clause: SELECT category FROM ( SELECT DISTINCT category FROM merchant ) t ORDER BY CASE WHEN category = 'General' THEN 0 ELSE 1 END, category ASC CASE guarantees that rows with General will be sorted first. The second argument orders the rest of the...

regex,perl,wolfram-mathematica

Square brackets are special characters in a regex. Try: $line =~ /^Out\[1\]=/ I'd recommend reading a regex tutorial like this one to learn this kind of thing....

c#,sorting,numbers,order,int32

Not that my answer may or may not be more "efficient", but when I read your code you calculated how many digits there are in your number so you can determine how large to make your array, and then you calculated how to turn your array back into a sorted...

Got it! I had already read the documentation before posting the question, but haven't had the click that lead me to the solution. This section on structuring data holds the answer: https://www.firebase.com/docs/ios/guide/structuring-data.html Understand: The natural structure would be: - champs - champID - matches - matchID - <matchData> - champName...

ruby-on-rails,ruby,tags,order,tag-cloud

The query will only take the first order into consideration. You can override it with reorder however this won't work in your case since it will override the order("taggings_count DESC"). What works for you is sort: @tags = Tag.all.top_20.sort{ |x,y| x.id <=> y.id }...

A batch file solution isn't much fun, because batch can't really count or deal with arrays and indexes, it needs to work like: setup a counter, list the files, count through them, when the count matches the number you want, do something. @echo off setlocal enabledelayedexpansion set i=0 for %%f...

python,dictionary,order,nested

Putting the content of a regular unordered dict into an ordered dict will not magically restore the order of the values in the unordered dict. There are some things you could do, though: Create example1 as an OrderedDict, too, so its values are ordered; but pass the items as a...

You can simply specify the distance calculation (say for example its (Longitude + Latitude) divided by 42) in the order by clause select ID, Name, Latitude, Longitude, (Longitude + Latitude) / 42 as Distance from YourTable order by (Longitude + Latitude) / 42 However, because the distance calculation is likely...

The problem is the 'inexact' floating point value of W=1.2. If you use W=12/10 you get a result. Note in this case you actually get a faster/cleaner result if you leave all the numeric values out except for X until after integration: Clear[d,W,Rm,X]; f = 1/(1 - R^2/Rm^2); A =...

order,openerp,odoo,odoo-8,kanban

One method I use to to odd sortsis use the context to control it. In the window action for the kanban view, add a context like <field name="context">{'do_my_special_sort': True}</field> and then on the model, override the search method, check for this flag in the context and set the sort order....

The thing is that .col-md-x set x columns for devices >= 940px, when the width is below that, the grill will show vertically, so the second col-md-6 (part-two) goes underneath of the first one(part-one) whit all its content, then having said that. You can use: <div class="row"> <div class="col-md-6"> <p>PARAGRAPH...

order,prestashop,prestashop-1.6

if you have the the price with tax and the price without tax you can calculate the tax amount and store the value in variable: {assign var='totalTax' value=$total_products_wt - $total_products} {displayWtPriceWithCurrency price=$totalTax currency=$currency}</span> ...

Presumably, ascending order. :) Kidding. If you mean "order of magnitude", the following solution will be O(m+n) or O(max(m,n)) where m is l1.length and n is l2.length. Algorithm: Keep a pointer to each linked list, step through both, and add the lesser of the two elements. If the elements are...

sorting,elasticsearch,group-by,order

Edit to reflect clarification in comments: To sort an aggregation by string value use an intrinsic sort, however sorting on non numeric metric aggregations is not currently supported. "aggs" : { "order_by_title" : { "terms" : { "field" : "title", "order": { "_term" : "asc" } } } } ...

you can use reorder and interaction between groups and Category like this ggplot(df,aes(x=reorder(interaction(Category, Group), -Amount, sum),y=Amount)) + geom_bar(stat='identity') + facet_wrap(~Group,scales='free_x') + labs(title="Some Random Histogram with Facets") ...

Since you are specifying the ordinal domain, dc.js will used that instead of calculating it using the existing values and the ordering you specify. Simply remove the domain and specify the ordering: .x(d3.scale.ordinal()) .ordering(function(kv) { return -kv.value; }) Fork of your fiddle: http://jsfiddle.net/0p78m8vr/6/...

You can put the categories in the desired order by converting COS to a factor: df$COS = factor(df$COS, levels=c("A","D","C","B")) ...

php,mysql,activerecord,order,yii2

First you should create ActiveRecord class for video and likes tables to make things easier. The aim is to create the two following classes class Video extends \yii\db\ActiveRecord and class Likes extends \yii\db\ActiveRecord. To do it easily, you should look at gii utility which will do it for you (available...

Let NSMutableArray handle the sorting with one of its sorting methods (e.g. sortUsingComparator:): NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"dd-MMM-yyyy HH:mm:ss"]; [aux sortUsingComparator:^NSComparisonResult(NSString *datestring1, NSString *datestring2) { NSDate *date1 = [dateFormatter dateFromString:datestring1]; NSDate *date2 = [dateFormatter dateFromString:datestring2]; return [date1 compare:date2]; }]; SIDENOTE: You should also consider converting the date...

You may utilize integer part of the table to store keys in order: function add(t, k, v, ...) if k ~= nil then t[k] = v t[#t+1] = k return add(t, ...) end return t end t = add({ }, "A", "hi", "B", "my", "C", "name", "D", "is") for i,k...

python,django,order,django-queryset

You should use, tutteIn = MktIn.objects.all().order_by('id_squadra__nome', 'ruolo', '-ingaggio') It's your field name, not the model name....

java,data-structures,order,comparator

The TreeSet won't reorder itself when you change the value of the elements. You have to take the elements out and re-add them if you want them to remain ordered: Node first = ts.pollFirst(); first.s--; ts.add(first); ...

The only way to do it in a "single step" is to define a method, use the BitConverter: public static int ReverseByteOrder(int value) { byte[] bytes = BitConverter.GetBytes(value); Array.Reverse(bytes); return BitConverter.ToInt32(bytes, 0); } Usage: int value = 0x1480D604; //or parse from string int decValue = ReverseByteOrder(value); //decValue = 0x04D68014 IsLittleEndian...

Here you go: public static String reverseName (String name) { name = name.trim(); StringBuilder reversedNameBuilder = new StringBuilder(); StringBuilder subNameBuilder = new StringBuilder(); for (int i = 0; i < name.length(); i++) { char currentChar = name.charAt(i); if (currentChar != ' ' && currentChar != '-') { subNameBuilder.append(currentChar); } else...

wolfram-mathematica,wolframalpha,wolfram-language

After the usual lots of trial and error that WolframAlpha didn't understand, finally WolframAlpha PrimeOmegaPlot link...

You cannot get the documents enumerated with position right from MongoDB. Thus that your manual job to do. The second problem is getting the neighbours. If you knew in advance the position of the required document, say i, you could do just .skip(i - 1).limit(3), and would get your neighbours...

At first the vectors in C# are called Arrays ;-) In a nutshell you are comparing products with the wrong prices. But why? Let me show this with an example: There are two important arrays: drycker: Prices: Cola -> 25 Fanta -> 20 Sprite -> 30 When you compare Cola...

You can pass a custom function to sort using the key parameter like this: from math import sqrt def get_ordered_list(points, x, y): points.sort(key = lambda p: sqrt((p.x - x)**2 + (p.y - y)**2)) return points ...

You can simply add the SUM function to the ORDER BY caluse: Select bus.trans_comp_id, SUM(bus.passengers*trips.cost) From bus inner join trips on bus.ID=trips.bus_id group by bus.trans_comp_id order by SUM(bus.passengers*trips.cost) desc ...

wolfram-mathematica,wolfram-language

Switch may be useful, for example: Switch[ # , _String , StringLength[#] , _List , Length[#] , __ , Null ] & /@ { "abc", {1, 2, 3, 4}, Pi} {3, 4, Null} ...

matlab,wolfram-mathematica,matlab-figure,contour

The thing to keep in mind is that Mathematica is formula-oriented and is programmed in terms of mathematical variables, while Matlab is numerically oriented and programmed in terms of matrices and arrays. To evaluate a function of two variables on a grid, it is necessary to first generate that grid...

It seems my mistake could only affect things if the one "min" object was compared to itself. Not quite. It could also be caused if there were two different "min" objects. In the case of the list sorted this particular time, it can only happen if the item is...

r,function,order,sequence,rstudio

If you want a function that takes vectors A, B, C, and D and input and outputs a sorted version of them, you can try: sortAll <- function(A, B, C, D) sort(c(A, B, C, D)) And then you can run it with something like: A <- c(1,2,2,3) B <- c(5,6,7,8)...

sql,tsql,recursion,order,hierarchy

The easiest way would be to pad the keys to a fixed length. e.g. 038,007 will be ordered before 038,012 But the padding length would have to be safe for the largest taskid. Although you could keep your path trimmed for readability and create an extra padded field for sorting....

In Lua, the order that pairs iterates through the keys is unspecified. However you can save the order in which items are added in an array-style table and use ipairs (which has a defined order for iterating keys in an array). To help with that you can create your own...

html,css,twitter-bootstrap-3,order,multiple-columns

Added a custom class up-xs and down-xs for the two div's and set the xs width condition using media-query. HTML <div class="row"> <div class="col-md-9 down-xs">Content</div> <aside class="col-md-3 up-xs">Some aside text</aside> </div> CSS @media ( max-width: 480px ) { .row { display: flex; flex-flow: column; } .up-xs { order: 1; }...

algorithm,sorting,language-agnostic,order,priority

Perhaps you could use a legal-style paragraph numbering.: 1, 1.12, 1.12.1, 1.12.2, 1.12.2.5 and so on. You can always insert a new entity between existing entities by extending to a new level of '.1'. Quite how you stop users assigning absurdly high priorities to otherwise routine documents is another problem....

magento,search,order,magento-1.9

In magento every order has two IDs Order ID - is Magento internal order ID Order Increment ID - is the ID display on communicate (email, etc) with your customer See Confusion with order id, order increment id and I am not getting order id as 20001201 To load order...

You have all of your details in $klantgegevens, and that that data is all shown in one row. That will cause you problems. It appears you have not normalized your data in your database. I suggest creating a table name something like customerDetails and then including rows such as id,...

php,mysql,performance,order,records

You can do this with a LIMIT clause, all you have to do is make sure your WHERE clause filters out categories you don't want. Try this: SELECT * FROM myTable WHERE category NOT IN(category, list) ORDER BY popularity DESC LIMIT 3; The way you'll pass in the list is...

sql-server,date,casting,order,group

If you really need to apply different formatting, you can do it using a derived table: select DATENAME(MM, [date]) + ' ' + CAST(DAY([date]) AS VARCHAR(2)) AS [DD Month], total_quantity from ( SELECT CAST([Datetime] AS DATE) AS [date], SUM(quantity) as total_quantity FROM Invoice_Itemized ii INNER JOIN Invoice_Totals it ON it.Invoice_Number...

use gulp-sort to get the file in alphabetical sequence. The plugins do output the files in the sequence in which they receive it, hence the sequence of files is even out of their control. and its actually good that they dont sort the files, the plugin should only do what...

One possibility would be to find the cumulative maxima of the vector, and then extract unique elements: unique(cummax(a)) # [1] 2 5 6 8 ...

Here is one approach, make two lists, one list for upper range of the erros: dataPLUS = {{0, 0.10981309359605919 + 0.05240427422664753`}, {0.2145, 0.09146326059113304 + 0.034195343626358385`}, {0.4290, 0.08230438177339898 + 0.02533205817067696`}, {0.6435, 0.0768141842364532 + 0.020205473852635995`}, {0.8580, 0.07223473349753692 + 0.016156209168991867`}, {4, 0.056122650246305375 + 0.009288720442961331}}; another list for the lower range of the errors...