Short Question: Lets say, I want to solve Project Euler problem 9 using python and some equation solving libraries. a + b + c = 1000. a2 + b2 = c2 How do you do it. Long Question: I want to solve a set of equations; linear, sometimes may be quadratic too. Not a specific problem; but often, I have been in situation I wanted to. I...
Is it possible without using exponentiation to have a set of numbers that when added together, always give unique sum? I know it can be done with exponentiation (see first answer): http://stackoverflow.com/questions/1619379/the-right-way-to-manage-user-privileges-user-hierarchy But I'm wondering if it's possible without exponentiation....
Does anybody have experience programming for both the Intel Math Kernel Library and the AMD Math Core Library? I'm building a personal computer for high performance statistical computations and am debating on the components to buy. An appeal of the AMD Math Core library is that it is free, but I am in academia so the MKL is not that ex...
I've got an IR sensor which writes its current information to a token which I then interpret in a C# application. That's all good -- no problems there, heres my code: SetLabelText(tokens [1],label_sensorValue); sensorreading = Int32.Parse(tokens[0]); sensordistance = (mathfunctionhere); Great. So the further away the IR sensor is from...
I have two variables: $qty = 7; $_POST['qty'] = 6; var_dump($qty, $_POST['qty']); // both vars are integers $_SESSION['qty'] = $qty + $_POST['qty']; echo '='.$_SESSION['qty']; This returns: int(7) int(6) =1 (int)$qty, (int)$_POST['qty'] doesn't solve the problem. What am I doing wrong? Update: ... intval($qty) + intval($_POST['...
Given a 4x4 matrix, what formula could i apply to each (x,y) cell to yield an (x,y) if the matrix was rotated 90 degrees to the right? I tried iterating over each cell but different cells gave different formulas. Given the following matrix of values. 0| | | | | 1| | | | | 2| | | | | 3| | | | | ------------- ...
If you're optimizing for an architecture on which branching is expensive (say the PS3's cell processor), it can be important to be able to determine whether or not you can express a given algorithm without using branches or at least using fewer branches. One pattern that I see a lot in unoptimized code is a bunch of if's used to tweak a...
What would be the best way to do the following. Enter a very long number, lets say 500,000 digits long without it going into scientific notation; and then am able to do math with it, like +2 etc.? Thank you in advance. EDIT: It is a 500,000 digit, positive integer. ...
This is really weird, and I cannot see why this is happening. In the foreach cycle, I am iterating through a class A collection, and for each class, I call the Count() method, where r1 and r2 numbers are generated from range [-1,1]. The problem is that Random.Next returns the same "random" numbers for each instance. When the results for...
I want to make a short URL service for 2 million assets but I want to use the shortest number of possible characters. What is the math equation that I would need to use to figure it out? I know it has something to do with factorials, right? ...
How can I write an algorithm that given a floating point number, and attempts to represent is as accurately as possible using a numerator and a denominator, both restricted to the range of a Java byte? The reason for this is that an I2C device wants a numerator and denominator, while it would make sense to give it a float. For example,...
Hello There, I want to order a result by fieldx * fieldy, for example: Row 1: fieldx = 10 fieldy = 10 Total: 100 Row 2: fieldx = 11 fieldy = 5 Total: 55 Row 1 has to appear first. Couldn't find anything about it. It's for a codeIgniter project, so if there is a solution with that I'm very happy. Thanks! ...
I have an I2C device that wants two inputs: a denominator and a numerator. Both are written to separate addresses, so no actual calculation (numerator/denominator) is done. The problem with this is that a divide by zero could occur on the I2C device, so a divide by zero error needs to be checked for. Ideally, exactly the same thing would...
I'm running a contest on a website and I have 3215 entrants who are eligible for 5x Sony PSPs. I believe the formula to count the odds is totalEntrants - prizes / prizes: (3215-5)/5 = 642 so that's an odds of 642 to 1 of winning - is that right? ( I suck at math ) And in my table which contains 3215 rows in the database I would just s...
Hi, guys, If I got a polynomial curve, and I want to find all monotonic curve segments and corresponding intervals by programming. What's the best way to do this... I want to avoid solving equation like f'(x) = 0; Using some nice numerical ways to do this,like bi-section, is preferred. f'(x) expression is available. Thanks. Add addit...
I wrote a tool for polar functions. It lists values from an input range like that: 0 Grad: (0 RAD|1 RES) 20 Grad: (0.349065850398866 RAD|1.3639702342662 RES) 40 Grad: (0.698131700797732 RAD|1.83909963117728 RES) 60 Grad: (1.0471975511966 RAD|2.73205080756888 RES) 80 Grad: (1.39626340159546 RAD|6.67128181961771 RES) 100 Grad: ...
I need to represent calculator key presses by the text for the keys to press surrounded by a box. I tried to get away with just the bare key presses (no box) but I got marked down for it because it would appear my assessor is a bit of a pedant. Anyway, a bit of research turned up the likes of \boxit and \fbox. I gave them both a go but...
When I type this into the Visual Studio 2008 immediate window: ? .9 - .8999999999999995 It gives me this as the answer: 0.00000000000000055511151231257827 The documentation says that a double has 15-16 digits of precision, but it's giving me a result with 32 digits of precision. Where is all that extra precision coming from? ...
I been looking at the recent blog post by Jeff Atwood on Alternate Sorting Orders. I tried to convert the code in the post to C# but I ran into an issue. There is no function in .NET that I know of that will return the z-value, given the percentage of area under the standard normal curve. The recommended values to use for the algorithm a...
Hello, how can I change with CSS (-moz-transform) a div that should look like this: ...