Inline function at -O0 causes link failure in clang [duplicate]
c,optimization,clang,inline,c99
At -O1 and greater it is not calling the function it just moves the code into main, we can see this by using godbolt which shows the asm as follows see it live: main: # @main pushq %rax movl $.L.str, %edi movl $42, %esi xorl %eax, %eax callq printf xorl...
Does compiler optimize operation on const variable and literal const number?
You have some good answers already that answer your factual question: No, the C# compiler does not generate the code to do a single multiplication by 86. It generates a multiplication by 43 and a multiplication by 2. There are some subtleties here that no one has gone into though....
Slow start-up of large programs
It turns out the delay is the Microsoft antivirus program scanning the executable each time it's run. Disabling protection on that file cuts the time to 47 milliseconds.
Compiling SCIP: 'spxsolver.h' file not found
The problem was that I was installing the scip-3.1.1.tgz rather than scipoptsuite-3.1.1.tgz. Running make on scipoptsuite-3.1.1.tgz runs perfectly fine.
Picking Ad Mob Mediation Networks 2015
MillenialMedia - Pretty decent engineering. Pretty good revenue Inmobi - Good revenue. Sometimes really dodgy ads. I've experiemented with half a dozen others, but they provided insignificant revenue, or provided many bugs. But your mileage may vary....
Optimization Toolbox (fmincon) - How to set logical constraints?
What you are looking for are nonlinear constraints, fmincon can handle it (I only know the command, not the GUI) with the argument nonlcon. For more information look at this guide http://de.mathworks.com/help/optim/ug/fmincon.html How would you implement this? First create a function function [c, ceq] = mycondition(x) c = -max(x)/min(x)/10; ceq...
Delivery optimization with limits
Try looking at it as a bipartite graph, trying to maximize the flow: Order the distances between the cities and the labs from closest to farthest, then iterate over the list and: Move x samples from the city to the lab - where x=min(max_lab_capacity, number_of_samples). The edge between the city...
How to interpret the output of the CPLEX interactive optimizer?
The % gap is the relative difference between the best solution and the best known bound for a solution. This is guaranteed to be higher than the gap between the best known solution and the true global optimum. In your case, the best bound is 83.9275, the best bound is...
Algorithms for minimizing single-variable functions
algorithm,optimization,numerical-methods
For this setting, I'd go with Golden Section Search. Convexity implies unimodality, which is needed by this method. Conversely, this method does not need derivatives. You can find derivatives numerically, but that's another way of saying "multiple function assessments"; might as well use these for golden-section partitions. ...
NumPy: How to avoid this loop?
I am not sure what you exactly want to do, but are you aware of scipy.ndimage.measurements for computing on arrays with labels? It look like you want something like: cLoss = len(dist_) - sum(TLabels * scipy.ndimage.measurements.sum(TLabels,dist_,dist_) / len(dist_)) ...
Optimizing a large if-else branch with binary search
c,optimization,binary-search,linear-search
You should look at the generated instructions to see (gcc -S source.c), but generally it comes down to these three: 1) N is too small. If you only have a 8 different branches, you execute an average of 4 checks (assuming equally probable cases, otherwise it could be even faster)....
Mysql optimize to avoid table scan
mysql,sql,table,optimization,scan
You could try a self join like this: SELECT COUNT(DISTINCT sw1.word_id) FROM sentence_word sw1 JOIN sentence_word sw2 ON ( sw1.sent_id = sw2.sent_id AND sw2.word_id = [your word id] ) WHERE sw1.word_id != [your word id] or perhaps even better SELECT COUNT(DISTINCT sw1.word_id) FROM sentence_word sw1 JOIN sentence_word sw2 ON (...
type conversion performance optimizable?
c#,xml,csv,optimization,type-conversion
IEnumerable<string> values = new List<string>(); values = … Probably not going to be a big deal, but why create a new List<string>() just to throw it away. Replace this with either: IEnumerable<string> values; values = … If you need values defined in a previous scope, or else just: Enumerable<string> values...
Optimization: memcached vs mysql memory
So, memcached is better and faster! BUT: memcached can remove old keys, if ttl expires or small size for sets other keys. The situation may be: In first request you set key-value to memcached. In second request (parallel) you set another key value to memcached, and in memcached small memory...
Does LINQ make use of underlying data structure?
They do where it makes sense, typically not for the actual type but for an interface (for example they check for IList when it helps speedup)
Why do we need to put the *.odex files under /system/app even if we already have /data/dalvik-cache?
android,optimization,virtual-machine,loader,dalvik
The /system/app directory is read-only on normal (non-developer) devices, and only updated when the system receives an update. The point of /system/app/*.odex is that the .odex file can be delivered as part of a system update, so it doesn't have to be generated on the first post-update boot, and doesn't...
How to write Max(L)<1 without using MAX func in MATLAB
every element of the vector L must be less than or equal to 1. This should be written as a set of constraints, not a single constraint. Artificially bundling the constraints L(1)<=1, L(2)<=1, ... into one constraint is just going to cause more pain to the solver. Example with...
Speeding up a function involving mapply and integrate
r,optimization,integrate,mapply
You are performing a large number of independent integrations. You can speed things up by performing these integrations on separate cores simultaneously (if you have a multicore processor available). The problem is that R performs its calculations in a single threaded manner by default. However, there are a number packages...
Placing Limits on Optim
r,optimization,regression,rscript
This seems to work fine: opt1 <- optim(startparam, fn=ls,method="L-BFGS-B", Val=Val,Hi=Hi,Di=Di, lower =c(20,10,0), upper =c(100,70,25)) note that the values of Val, Hi, Di get passed through optim to the objective function....
make all elements in list equal with minimal cost
Determinstic variant First a more efficient but deterministic approach: occurs_most([],_,0). occurs_most(List,X,Nr) :- msort(List,[H|T]), most_sort(T,H,1,H,1,X,Nr). most_sort([Hb|T],Ha,Na,Hb,Nb,Hr,Nr) :- !, Nb1 is Nb+1, most_sort(T,Ha,Na,Hb,Nb1,Hr,Nr). most_sort([Hc|T],_,Na,Hb,Nb,Hr,Nr) :- Nb > Na, !, most_sort(T,Hb,Nb,Hc,1,Hr,Nr). most_sort([Hc|T],Ha,Na,_,_,Hr,Nr) :- most_sort(T,Ha,Na,Hc,1,Hr,Nr). most_sort([],Ha,Na,_,Nb,Ha,Na) :- Na >= Nb, !. most_sort([],_,_,Hb,Nb,Hb,Nb). First you use msort/2 to sort the list. Then you iterate over...
nuZ: Use of soft-assertions with weights and ids
By default Z3 solves the objectives one at a time and finds the lexicographically best solution. First it tries to satisfy as many soft constraints from "first". The weight you associate with the soft constraints is a penalty for not satisfying the constraint. That is, it is not an award,...
Optimizing a sub-sub-query in MySQL
If you want only the most recent comment for a given user, then you can express this as: SELECT rc.* FROM requests r JOIN requests_comments rc ON rc.request_id = r.id WHERE r.username = 'someuser' ORDER BY rc.commented_at DEC LIMIT 1; For performance, you want an index on requests(username, id) and...
glclearcolor best color?
No (technically there could be a difference, since OpenGL does not impose any performance requirements on the functioncall). Btw. you should set the clear color before calling clear....
(Java) Efficiency in my Starter Bubble Sort
java,algorithm,optimization,foreach,bubble-sort
Using indexOf is not correct, if your ArrayList x contains more than one value of i, your sort method will behave incorrectly. For example, this case: [5, 5, 1] After running your program, return [5, 5, 1] Plus, using indexOf, as mentioned by tucuxi, will slow down your program....
Alpha blending using table lookup is not as fast as expected
c,performance,optimization,alphablending,lookup-tables
Table lookup is not a panacea. It helps when the table is small enough, but in your case the table is very big. You write 16 megabytes used for the table is not an issue in this case which I think is very wrong, and is possibly the source of...
How can I optimize filename generator with underscore?
Note that there are 2n-1 different such names for a string of lengh n, as there can or can not be a _ between any two characters. For your long-long name that makes 134,217,728 variants! Regardless of what algorithm you use, this will take a very long time. One way...
Is there a more efficient way to solve this?
python,python-2.7,optimization,matrix
In terms of refactoring, you almost certainly want to avoid "brute force" in the sense of having to explicitly type out all your cases :) @alexmcf addresses this above. In conceptual terms, your approach follows the problem statement directly: check all neighbors for each number in the matrix and sum...
Add a python flag cx_freeze to executable
python,optimization,distribution,cx-freeze,pyglet
You can use the same -O flag when you run cx_freeze to generate your final build, meaning that the cx_freeze generated bytecode will already be optimized. From the cxfreeze docs: cxfreeze hello.py --target-dir dist Further customization can be done using the following options: ... -O optimize generated bytecode as per...
More efficient way to get nearest center
You should rather use the optimized cdist from scipy.spatial which is more efficient than calculating it with numpy, from scipy.spatial.distance import cdist dist = cdist(data, C, metric='euclidean') dist_idx = np.argmin(dist, axis=1) An even more elegant solution is to use scipy.spatial.cKDTree (as pointed out by @Saullo Castro in comments), which could...
Disable JRockit Optimzation per class
optimization,jvm-hotspot,jrockit
You can create an opt file, see JRockit R28: http://docs.oracle.com/cd/E15289_01/doc.40/e15059/crash.htm#BABJGICB Earlier releases: https://docs.oracle.com/cd/E13150_01/jrockit_jvm/jrockit/geninfo/diagnos/crash.html#wp1010461...
Better to declare JavaScript Object inside for loop or outside in terms of time optimization
javascript,arrays,optimization,variable-declaration
Both are the same. for loops don't create a new scope so the variables are hoisted to the top of the containing function scope. ex: > i undefined > for (var i = 0; i < 5; i++) { var test = i; } undefined > i 5 > test...
FastDOM - Read / write every 17ms?
javascript,dom,optimization,asynchronous,requestanimationframe
Both types of DOM operations (read/write) have their own job queues. Each queue is flushed (e.g. all jobs in it are ran/executed) every requestAnimationFrame If you add 100 read operations all within 5ms, for example, (during a loop for instance), all of those read operations will (most likely) occur the...
(WHY?) Greatest+Coalesce way faster than a single select with or
(GREATEST and COALESCE are not relevant to the real question.) It may or may not be faster. Here's the logic... OR usually eliminates using an index. SELECT ... ORDER BY indexed_column LIMIT 1 may be able to use indexed_column to find the 1 row you want with no extra effort....
Hashmap with time values, want to find value at specific second
You don't need a (Linked)HashMap for this job. Use a NavigableMap (TreeMap would be the standard implementation) that provides a lot of useful operations for such use-cases: floor/ceiling, higher/lower, first/last and so on. // get the value at this specific time or the last one before that Double valueAtTheTime =...
Minimize a function with two variables
There are a few problems with your overall process that cause trouble. First of all as @user227710 mentions in the comments you should replace && with &. These have different meanings. Now for the optimiser It looks like you want to set limits to your parameters (i.e. what is known...
code optimising for if-else function
Here is an answer. First remove all the branches and then implement as SSE. I haven't check the speed yet. const int T1 = 17560; const int T2 = 244583; const int SHIFT = 16; int A = 2*((dx ^ dy) >= 0)-1; //check (dy,dx) opposite sign dy = abs(dy);...
Optimizing for Social Leaderboards
python,google-app-engine,optimization,twitter,leaderboard
I would organize the task like this: Make an asynchronous fetch call to the Twitter feed Use memcache to hold all the AuthAccount->User data: Request the data from memcache, if it doesn't exist then make a fetch_async() call to the AuthAccount to populate memcache and a local dict Run each...