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  • How can I perform a reverse string search in Excel without using VBA?

    - by e.James
    I have an Excel spreadsheet containing a list of strings. Each string is made up of several words, but the number of words in each string is different. Using built in Excel functions (no VBA), is there a way to isolate the last word in each string? Examples: Are you classified as human? - human? Negative, I am a meat popsicle - popsicle Aziz! Light! - Light!

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  • approximating log10[x^k0 + k1]

    - by Yale Zhang
    Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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  • Is SQL DATEDIFF(year, ..., ...) an Expensive Computation?

    - by rlb.usa
    I'm trying to optimize up some horrendously complicated SQL queries because it takes too long to finish. In my queries, I have dynamically created SQL statements with lots of the same functions, so I created a temporary table where each function is only called once instead of many, many times - this cut my execution time by 3/4. So my question is, can I expect to see much of a difference if say, 1,000 datediff computations are narrowed to 100?

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  • Is there something like clock() that works better for parallel code?

    - by Jared P
    So I know that clock() measures clock cycles, and thus isn't very good for measuring time, and I know there are functions like omp_get_wtime() for getting the wall time, but it is frustrating for me that the wall time varies so much, and was wondering if there was some way to measure distinct clock cycles (only one cycle even if more than one thread executed in it). It has to be something relatively simple/native. Thanks

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  • mvc external javascript referencing problem

    - by user281180
    I recently asked this question but to my suprise, it worked fine for some time and now has stopped again! I have a javascript in my script and I have added the link in my view as follows: It has certain functions which I can access once I have the script in my view. But when running I can see that the fucntions are not called instead i`m getting the error message Object expected at line 104. Why am I having this error and how can I solve it?

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  • Numpy: Creating a complex array from 2 real ones?

    - by Duncan Tait
    I swear this should be so easy... Why is it not? :( In fact, I want to combine 2 parts of the same array to make a complex array: Data[:,:,:,0] , Data[:,:,:,1] These don't work: x = np.complex(Data[:,:,:,0], Data[:,:,:,1]) x = complex(Data[:,:,:,0], Data[:,:,:,1]) Am I missing something? Does numpy not like performing array functions on complex numbers? Here's the error: TypeError: only length-1 arrays can be converted to Python scalars Cheers

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  • PostgreSQL function question

    - by maxxtack
    CREATE FUNCTION foo() RETURNS text LANGUAGE plperl AS $$ return 'foo'; $$; CREATE FUNCTION foobar() RETURNS text LANGUAGE plperl AS $$ return foo() . 'bar'; $$; I'm trying to compose results using multiple functions, but when i call foobar() i get an empty result.

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  • Dreamweaver javascript code hints

    - by xdevel2000
    I'd to use DW cs 4 but before to buy I want to test javascript code hints. However that feature doesn't work at all. I have an external .js library and then into an html file I load it but when I type functions or object by name nothing happen. Any idea?

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  • wordpress my_deregister plugin from page

    - by musiC addicted
    i try to use the next code to load cforms II plugin only on my CONTACT PAGE (http://www.deliciousdays.com/cforms-plugin/) #/template/functions.php add_action( 'wp_print_scripts', ' ', 100 ); function my_deregister_javascript() { if ( !is_page('Contact') ) { wp_deregister_script( 'cforms' ); } } add_action( 'wp_print_styles', 'my_deregister_styles', 100 ); function my_deregister_styles() { if ( !is_page('contact') ) { wp_deregister_style( 'cforms' ); wp_deregister_style( 'style' ); } } but doesn't work the code worked for contact form 7 ( http://wordpress.org/extend/plugins/contact-form-7/)

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  • How to combine query strings in PHP

    - by incrediman
    Given a url, and a query string, how can I get the url resulting from the combination of the query string with the url? I'm looking for functionality similar to .htaccess's qsa. I realize this would be fairly trivial to implement completely by hand, however are there built-in functions that deal with query strings which could either simplify or completely solve this? Example input/result sets: Url="http://www.example.com/index.php/page?a=1" QS ="?b=2" Result="http://www.example.com/index.php/page?a=1&b=2" - Url="page.php" QS ="?b=2" Result="page.php?b=2"

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  • Preventing server-side scripting, XSS

    - by Tim
    Hey all Are there any pre-made scripts that I can use for PHP / MySQL to prevent server-side scripting and JS injections? I know about the typical functions such as htmlentities, special characters, string replace etc. but is there a simple bit of code or a function that is a failsafe for everything? Any ideas would be great. Many thanks :)

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  • class vs structure c#

    - by Enriquev
    I'm doing course 3354 (Implementing System Types and Interfaces in the .NET Framework 2.0) and it is said that for simple classes, with members variables and functions, it is better to use a struct than a class because of overhead. I have never heard of such a thing, what is the validity of this claim?

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  • Why is my Android emulator keyboard in Japanese character mode?

    - by mckoss
    I'm debugging my Android application using the AVD (Android Virtual Device). When I try to enter text in a text field, my characters are being interpreted as Japanese (or Chinese?) in the IME. I don't know how I got into this mode or how to get out of it (I just want to enter alphabetic keys)? Here's a screen shot: http://u.go2.me/3cn

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  • output with "Private`" Content in Mathematica Package

    - by madalina
    Hello everyone, I am trying to solve the following implementation problem in Mathematica 7.0 for some days now and I do not understand exactly what is happening so I hope someone can give me some hints. I have 3 functions that I implemented in Mathematica in a source file with extension *.nb. They are working okay to all the examples. Now I want to put these functions into 3 different packages. So I created three different packages with extension .*m in which I put all the desired Mathematica function. An example in the "stereographic.m" package which contain the code: BeginPackage["stereographic`"] stereographic::usage="The package stereographic...." formEqs::usage="The function formEqs[complexBivPolyEqn..." makePoly::usage="The function makePoly[algebraicEqn] ..." getFixPolys::usage="The function..." milnorFibration::usage="The function..." Begin["Private`"] Share[]; formEqs[complex_,{m_,n_}]:=Block[{complexnew,complexnew1, realeq, imageq, expreal, expimag, polyrealF, polyimagF,s,t,u,v,a,b,c,epsilon,x,y,z}, complexnew:=complex/.{m->s+I*t,n->u+I*v}; complexnew1:=complexnew/.{s->(2 a epsilon)/(1+a^2+b^2+c^2),t->(2 b epsilon)/(1+a^2+b^2+c^2),u->(2 c epsilon)/(1+a^2+b^2+c^2),v->(- epsilon+a^2 epsilon+b^2 epsilon+c^2 epsilon)/(1+a^2+b^2+c^2)}; realeq:=ComplexExpand[Re[complexnew1]]; imageq:=ComplexExpand[Im[complexnew1]]; expreal:=makePoly[realeq]; expimag:=makePoly[imageq]; polyrealF:=expreal/.{a->x,b->y,c->z}; polyimagF:=expimag/.{a->x,b->y,c->z}; {polyrealF,polyimagF} ] End[] EndPackage[] Now to test the function I load the package Needs["stereographic`"] everything is okay. But when I test the function for example with formEqs[x^2-y^2,{x,y}] I get the following ouput: {Private`epsilon^2 + 2 Private`x^2 Private`epsilon^2 + Private`x^4 Private`epsilon^2 - 6 Private`y^2 Private`epsilon^2 + 2 Private`x^2 Private`y^2 Private`epsilon^2 + Private`y^4 Private`epsilon^2 - 6 Private`z^2 Private`epsilon^2 + 2 Private`x^2 Private`z^2 Private`epsilon^2 + 2 Private`y^2 Private`z^2 Private`epsilon^2 + Private`z^4 Private`epsilon^2, 8 Private`x Private`y Private`epsilon^2 + 4 Private`z Private`epsilon^2 - 4 Private`x^2 Private`z Private`epsilon^2 - 4 Private`y^2 Private`z Private`epsilon^2 - 4 Private`z^3 Private`epsilon^2} Of course I do not understand why Private` appears in front of any local variable which I returned in the final result. I would want not to have this Private` in the computed output. Any idea or better explanations which could indicate me why this happens? Thank you very much for your help. Best wishes, madalina

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