What is Array: Definition and 501 Discussions

Homework Statement hello, i have to find the limit of the next array (xn)=(cos (π/n+1) + cos (π/n+2) + ...+ cos ( π/2n))/n when n goes to infinity. Homework Equations I was told to apply stolz cesaro and that is where i ended up : the limit is : limit of cos ( π/2n+1) + cos (π/2n+2) -cos...

Hi evryone, i have started to write an "algorithm" that finds the Family of a given element in a table of 3 columns: Id, Source and Destination. When i say Family i mean each element (i.e. A) from Source that has a relation with another one in Destination and i have to find a family for that new...

I have large 2d matrices from dicom files that i wish to filter with a 3x3 mask. the image arrays are of varying size and are padded with one border of zeros for the edge handling of the mask. i need to iterate over every element in the array and multiply it by the mask. I've done it in SciLab...

Hi guys, I have a dicom image from a QC spect acquisition. reading the file in with dicom.read_file and pulling pixel data using numpy.pixel_array gives array of shape [2, 1024, 1024] The 2 represents two images, one from each detector head on the spect scanner and the 1024x1024 are the...

Homework Statement The problem is to show that arranging N into the two dimensional array: \begin{matrix} 1 & 3 & 6 & 10 & ... \\ 2& 5& 9& ... \\ 4& 8& & \\ 7&... & & \\ ... \end{matrix} leads to a proof that the union of an infinite number of countably infinite sets is countable...

Hello, thanks for your interest in may help me, i appreciate it, really. My question is, I've wrote this code to solve an physical EDO system. But for some reason it copies the element k[1][3] at k[2][3]. After i call the initials elements the code becomes: for ( int n=1 ; n<=1; n++ ){...

Hi, hopefully someone here can help me! I'm interested in Halbach Arrays and specifically I want to make a circular array in which the field is amplified away from the array (as in above or below it), not to its inner diameter (or exterior circumference). Is this possible? On the web I've seen...

of size N into an K subgroups. I've been trying for hours to do this and still haven't found a solution. Example: The array {A,B,C} of size N=3 and I want all the move combinations that make it into K=1 subgroups. The only such subgroup is the one with all the elements, and I can get that with...

I have this really noisy data and I'm wanting to plot Temperature v. Time. I used this function to calculate a moving average. Here's some sample code. BA1='ANP-Heat-BA1.csv' #Time Trial 1 time1=pd.read_csv(BA1,skiprows=0) time1=time1['Time(s)'] #Temperature tmp1=pd.read_csv(BA1,skiprows=0)...

Hello mathhelpboards community! Please help! Thank you. :-) I need my code to print out the user's original array that is to say the numbers in the way the user entered them. I tried making a copy of the original array and then did all of the arithmetic on it. I sorted the array copy in...

Here are my Fortran codes: program test implicitnone integer*4 nxProjPad, cf, numViews, cc, index, indRad, iv, i, INDEX1, d, n real*4 v4, v5, RSS, S1, F1, gMDL real*4, dimension(:), allocatable :: array, sum, cumsum, transpose, log, SS1, SSs nxProjPad=185 numViews=180...

I can't find this exact algorithm anywhere on the internet. What I'm trying to implement is the following function // Returns all subarrays of the given array, not including the empty array // ex. [a,b,c].subarrays() = [ [a], [b], [c], [a,b], [a,c], [b,c], [a,b,c] ] Array.prototype.subarrays...

I would like to ask how to use MATLAB to append new columns into existing excel file without altering the original data in the file? In my case I don't know the original number of columns and rows in the file and it is inefficient to open the files one by one and check in practice. Another...

Hi in my project their are three variables like speed ,depth of cut and feed and each variable have 5 values then please tell me which Orthogonal array is suitable for my design of experiments by using taguchi method And tell me detailed Thank you

I need help with this equation array. \begin{align} \bra{+}\hat{H}\ket{+}&=\frac{1}{2}(\bra{e}+\bra{o})\hat{H}(\ket{e}+\ket{o})\\ &=\frac{1}{2}(\bra{e}\ket{e}E_e+\bra{e}\ket{o}E_o+\bra{o}\ket{e}E_e\\ &+\bra{o}\ket{o}E_o)\\ &=\frac{1}{2}(E_e+E_o). \end{align} I just want it...

I have a a multidimensional array (49x49x49) which has NaN values scattered randomly. For each NaN, I want to replace the value with the previous non NaN value. e.g. if i had a 3 x 3 matrix 4 7 9 2 7 NaN 1 2 NaN should become 4 7 9 2 7 7 1 2 2 I have 3 dimensions [i,j,k], but...

I am having problems with printing out each elements of the array using a for loop It's suppose to look like this: Enter non-negative numbers (ints) terminated by -99 1 2 3 4 5 6 -99 Original list (6 values): 1, 2, 3, 4, 5, 6. the code's output looks like: Enter non-negative numbers (ints)...

Can a magnetic Halbach array have less than three (i.e. two) magnets in the array? I can't seem to figure this out quickly with google. TIA!

Hello everybody, I have a source code which gives me as a result an array of 2 columns and 3001 rows (2d array). By using fortran90. I was trying to have the values inside these cells into .dat file and tried to generate a subroutine and call my main array inside this. But somehow I get...

I need to normalize an array, I find the max value which can be any integer. I have to output this number using cout and represent it as 'x' how ever many times. The catch is I can only have a max amount of 60 x's. If my max is 500 I need to display it as 60 'x' and normalize my whole array to...

Hi, I need to write a subroutine that accepts as an argument an array of any number of dimensions, where each dimensions has any size. The array is contiguously allocated. In C, I can do this pretty cleanly. void array_func(int ndims, int *dims, int *array) { // do stuff with...

I have a program "probe.f90" that reads in a text file. It runs. I am having trouble reading in the second text file (when prompted by user). How could I turn this bit of code into a function? I was thinking about a function that strips the header from the fasta file. Then read into an...

Hi, I've been doing reading on Halbach Arrays moving over surfaces and generating repulsive forces. From my understanding, the moving magnet induces a circular electric current in the metal track, which gives rise to a magnetic field. However, I'm having trouble understanding why this field...

Hello, I'm extremely new to C++ and will appreciate any help you would be willing to offer. I need to create a function that will find the duplicate characters in a string and then when a duplicate is found, it will break out of the search loop and print the position of the character that was a...

I have a program that calculates the Fibonacci numbers from 1 to 100. The program runs fine. I am not sure how to take my output and display them in an ARRAY. Any ideas? I tired to pass the array variable through the equation, but my output was weird. I would have 1, 1, 3347...

Hi, I'm currently working on a project, and I need some info on halbach arrays. I have not taken University EM Physics yet (but have taken mechanics), so some of this is a bit over my head, but I have a few questions. Say I have a frictionless train, that is using a air bearings for lift, BUT...

Hi All! Haven't been here for some time, the changes are looking good! Anyway, formalities aside, I am having serious problems sourcing and implementing a suitable stainless steel (Grade: 304; thickness: 0.3mm) substrate for my etching process. I'm currently working on developing a...

Homework Statement I'm reading Zee's book Einstein Gravity, I'm in the section where he said that given an array of two numbers p=(ap1, bp2), it is not a vector unless a=b. He just stated it without really showing how it must be like that. I know that a vector should satisfy a transformation...

We have LED arrays for visible lighting. What problems exist for using infrared LED arrays as a heat source for humans, like those in a residential settings? Does effectiveness vary much by wavelength and skin color, clothing worn, etc? Thanks. :-)

Homework Statement The numbers 1 to 25 are arranged in a square array of five rows and five columns in an arbitrary way. The greatest number in each row is determined, and then the least number of these five is taken; call that number s. Next, the least number in each column is determined, and...

I have a list of factorials from 1 -100. I can print them to the console without a format problem. I used the kind() function for formatting the output. I have tried to put these numbers into an array, but I get an error when I try to print the array PRINT *, FACTORIALS (F) 1 Warning: Legacy...

I'd like to take several of these (or similar) usb device charging batteries (http://www.ianker.com/product/A1271011 ) and connect them into an array to create a minimum of 36V and channel that to power a speed controller for an electric vehicle. Is this possible? Would I be able to prototype...

Hi folks. I'm currently designing a 4000w LED chip array in which I plan on using 3x 1500w 12v switch mode power supply's. A DC-DC converter will convert the 12v to 35v powering two chips. This totals to 20 step up converters and 3 switch mode power supplies to drive the proposed 40 100w chips...

To increase the resolution of an instrument, smaller wavelength and larger aperture is desirable. It is mentioned in some textbooks that the "effective" diameter of a telescope can be increased by using arrays of smaller telescopes. I just wonder why it is possible because every telescope is...

Would it be possible to use diffraction to focus the enrgy of sea waves, on the principle of the zone plate (https://en.wikipedia.org/wiki/Zone_plate) but reduced to 2 dimensions? This could be done by an array of wave-opaque objects such as floating breakwaters, particularly along coasts...

Hi, I have a problem with a code I'm working with. I'm a student in physics and I'm writing a code in Fortran 90 that should calculate the Polonium's half-life time. I have no data to work with so I generated them with the library random number and here is the problem, I have a 300 lines code...

Hello, I'm currently engaged on a project where I need to design a 3x3 rectangular patch antenna array operating 1.5~5.8GHz on FR4 h=1.6mm substrate. I've studied the single element design and some TL matching techniques like the quarter wavelength but I can't put together a 3x3 elements...

Hi all, First time post, long time lurker, sorry if this is in the wrong section. I am currently looking at a project that requires a large solar panel array onto a very tight roof area; maximising space is therefore important. Thus, keeping the panels as close together is important. I have a...

I was reading this article " The Effect of Head Rotation on the Geometry and Hemodynamics of Healthy Vertebral Arteries" They used an MRI machine with a phased array head-neckcoil and a phased array superficial coil. what are they?

I'm making an array of 11 3.3V LEDs, and I've got multiple various setups possible depending on source voltage (batteries supplying either 6V, 9V, or 12V) and whether I decide to put a bunch of the LEDs in a combination of series/parallel or all in parallel. I need to maximize battery life, so...

Hello there, I again have a problem with programming in Fortran 90.1. Homework Statement I would like to construct an array with an implicit do loop. I know how to get the array I want to with usual do-loop but I would like to do it without do loops. So this is the array I want to construct...

Rotate an array hi everyone I'm hoping someone maybe able to help me/ point me in the right direction with the rotation of data from an array. I'll try to keep it short but my maths skills are seriously not good due to my old age and inexperience. I maybe approaching it from the wrong angle and...

Maybe I am going about this the wrong way. I'm trying to build a form to display & update information in a object. The objects are stored in an array since I'll have 1-N of them. What I've done now is created an array of dictonaries which hold the information about the form fields, it...

solar updraft tower: How small a working unit can be made? My reason to ask this question is: I think that if a commercial unit is ever to be built, first the concept must be widely established. One or two working examples of a size similar to the prototype built in Spain won't likely prove...

Hi, I'll give some background, say you've got a planar structure of thickness 'd', lying on the z plane. Also say the upper and lower surfaces are y = 0 and y = -d, respectively. The structure has scalar potentials inside it as so: As you can see the vector fields cancel out on one side, As it...

Im trying to pass an unknown size of array to the subroutine. Then I will define the size of array in subroutine and pass it back to main program. I tried to use interface but the complier said invalid memory reference or Explicit interface required for ' ' at (1): allocatable argument . Any...

Hi All, I'm working on a research project that requires putting an electrode array with 4 elements into a flexible tube filled with conductive liquid. The electrode array is a series of balls, with the first being positive and the last being negative. The idea is to measure the change in...

So I am fairly new to Python and feel somewhat comfortable with it. I am trying to do something what I think seems kind of simple however am not too experienced with loading files into Python (or any programming language for that matter). What I am trying to do is I have csv files that contain...

I want to create an array of numbers between 0 and 0.1 where the points are clustered around an arbitrary point x1 (0 < x1 < 0.1). I want the points to get exponentially closer together near x1 from either side and and get further apart towards the outer limits. I am using MatLab and was trying...

Homework Statement I made a two-dimensional array program, but now I need some help to alter the program in the print zone. The Attempt at a Solution import sys students = [] grades = [] while True: student = input ("Enter a name: ").replace(" ","") if...