Mathematica Definition and 1000 Threads

Does anybody know how i can make files in a do loop in mathematica? For example i want a do loop as (here is not mathematica language) do i=1,10 make file = text_i.txt (here i is the index of the do loop) end do The results of this process would be ten files as text_1.txt text_2.txt...

Hi, I have just started using Mathematica mainly for its symbolic math abilities; however, I have run into a small problem that I don't know how to fix. I have generated a matrix of dimensions: Dimensions[A] = {4,4,1} And I need to convert this to a matrix of dimensions...

I am currently working on an algorithm which will ultimately be able to take as input a 3 matrices, (R,G,B) and convert each pixel value into hue saturation and intensity values. So far I have been able to get all but the hue portion to work properly. Here is the code thus far...

How can I force : A Log[b] + A Log[c] to simplify to A Log[b c]? I tried, A,b,c all elements of reals, but it doesn't do it. (Assume everything is Real) I know I can make some patterned rules but I'd rather have it be by default. (i.e. : a_ Log[b_] + a_ Log[c_] :> a Log[b c])

Hi all, I have a 2nd order ODE I am trying to solve using NDSolve. In the ODE there are two constant coefficients and an initial condition that I want to 'vary'; meaning, I have a table of initial conditions with corresponding constant coefficients. It is straight forward to solve the ODE...

Hello , i wanted to ask sth I have a map : xn+1=rxne-xn , r>0 and r<20 I want to find fixed points .My problem is that i don't have a value or r.I can't manipulate the r values. (if i had an r value i would do : r=2;) My code is: y[x_]:= r x Exp[-x]; To find the fixed points ...

Hi everybody, This is my first post in this forum. So, "Hello everybody" ! I hope someone can help me. I started to learn Mathematica a few weeks back and really like the software. I actually prefer it over Matlab but that's just my personal opinion. I used 'Mathematica demystified' and...

I have three n x n matrices for which I am try to compute the saturation of each element in the matrix. The function to find this is S:=1-3(Min r,g,b) where r,g,b are the color channel matrices. For my output I am trying to get it to return an n x n matrix with each element having the function S...

Hi all, Does anyone know how to get Mathematica make a 3D plot with logarithmic axes? I need a, say, 3D version of LogLogPlot. I have a 3D function Rdb[nf, pf] which I want to plot for {nf, 10^10,10^18} and {pf, 10^10,10^18}. I can get cross sections of what I need when I do...

I want to plot a line in mathematica with a negative slope by setting it's starting point, length, and slope but i couldn't figure out how to do it. example: A line "AB" has a starting point (40,0) has a length 10 has an angle 127 degrees between x axisIn MATLAB i can do this with %% k =...

Hi I'm trying to solve this famous problem with Mathematica: "How many ways can a math professor incorrectly address Christmas cards so that no card gets to the originally intended recipient" I found a recurrence formula but don`t know how to implement it in Mathematica, this is the...

Hello everyone, I apologize for posting such an introductory mathematica question, but I can't find an answer anywhere. I seem to be having trouble assigning variables and then plotting with the variable name. Perhaps I'm thinking too much in terms of ordinary computer programming or...

Homework Statement I have to program a three component decay chain using finite difference approximation. I understand finite difference and have written my code, but I have an error I can not find which is giving me an erroneous answer. The curve is correct, but the magnitude of the...

Hi to everyone I'm new to this forum and if someone knows about formulas or how to generate the arithmetic and progression geometric and with the software Mathematica 5.0?! Both of these have starting member and step for calculation...Thanks in advance, G.S

Hi there. Well, I got a surface plotted with Mathematica. I've used the Plot3D command for this. But now I want to plot a point in the same graph. The thing is I've used Taylors polynomial of second degree, and I want to "see" the point around which I'm making the approximation. But I don't know...

How do I fit the data given below into the standard form (ignore the part saying to use MathCad): http://screensnapr.com/u/apmqkd.png {{{0.002, 0.726}, {0.022, 0.739}, {0.042, 0.75}, {0.062, 0.759}, {0.082, 0.768}, {0.102, 0.776}, {0.121, 0.785}, {0.141, 0.794}, {0.161, 0.802}...

While I know there exists: In[1]:= Timing[Integrate[blah]] Out[1]:= {result,time it took to calculate} Is there a way to just have the time it took to process a step appear in the Out[1]:= part, or after every step rather than having to use the Timing function and then pull out the...

I wish to compute Sum[f[i], {i, 0, m}] - Sum[f[i], {i, 0, j}] but can't get the expected result Sum[f[i], {i, j+1, m}] I also tried Sum[f[i], {i, 0, m}] - f[0] but can't get the expected result Sum[f[i], {i, 1, m}] It seems that mathematica can't change the minimum/maximum...

Hi everyone, i have a problem with mathematica. I am supposed to compute the eigenvalue of a matrix, and I need the expression for the eigenvalues analytically. But it output strange symbols. and I am unable to decipher what it means. What I got is an output consisting of words like root and...

Hi all, I am trying to evaluate and plot a function of two variable in mathematica. Function: R(t,\theta) = a(t) + b(t)*Y_n(\theta) Where a(t) and b(t) are functions (that I have evaluated already), and Y is the spherical harmonic for a given n, and R is the radius. In...

I'm trying to calculate several stuff about the electric field generated by 2 "plaques" My main problem being that in mathematica it calculates fast for a point of the electric field generated in the Y component, but if i try to make the median of all the points in the plaque it takes way to...

Hi, I'm currently working on a C program where I have a huge 2d array that changes with time, so in the end, what I have is a 3d array (double 25*24000*100) in a plain text file (about 700MB). I tried to import with Mathematica7 as a "Table" but after a long time (about 15 minutes) the kernel...

a\text{''}[t]+B[t]*a'[t]-A[t]*a[t]==0 a[0] = 10^-9 a'[0] = 0 a[t] = ? The coefficients A and B are variable over time. I HAVE solved (experimental and theoretical values) for the values of A and B over the time interval of interest! I attempted to solve for a[t] using NDSolve as one...

a\text{''}[t]+B[t]*a'[t]-A[t]*a[t]==0 a[0] = 10^-9 a'[0] = 0 a[t] = ? The coefficients A and B are variable over time. I HAVE solved (experimental and theoretical values) for the values of A and B over the time interval of interest! I attempted to solve for a[t] using NDSolve as one...

I want to plot this polynomial: Q10[x_] := c* (1 - (t - x)^2)^10 I defined variable 't' in f(t) and 'x' in the polynomial Q10[x]. how can I plot this polynomials with variebles x and t? the range-interval will be (for both x and t): [0,1]. can you write the code please... Thanks... Edit...

Hi all, Kinda new to Mathematica. I have evaluated a function describing a sphere's (or just circle for simplicity) radius over time. I have made a Table of values for the radius over a given time interval, and am able to plot the radius vs time. How can I make an animated 3D plot of...

Hi guys I am trying to plot a function with respect to T, but I want to rescale my axis. For example my range right now shows 0, 10, 20, 30. But I want it to show 0, 1, 2, 3 and so that I can then put an x-axis label of T/10. Can anyone help?

Just wonder if anyone in our little community is using Mathematica on Linux or Unbuntu. I have another license to use and a box with Unbuntu.

Hello everyone, I have a list, let's call it L1, of length N. Each element of this list is a square matrix. I would like to : 1/ Apply MatrixExp[] to each element of L1 (I know how to do that) 2/ Multiply each element of the subsequent list _in an ordred fashion_ i.e. from element N to...

Hi guys, I am writing a code for mathematica... I have two lists for t(time) and T(temperature) such that t=(t1,t2,t3...tn) and T=(T1,T2,T3,T4,T5...Tn) I have a formula that needs me to correspond the values in the two lists...which means... T1 is the value recorded at t1... any...

Hi folks, i just want to call different functions which are solutions of set of rate equations from s= NDSolve in a loop to calculate something. For[k = 0, k < 27, k++, x[k] = N#[time] /. s; ] # is just an arbitrary sign. i just want to replace # with k so i call N0[time]...

OK, here's a problem I'm trying to solve for my work. Given a set of n points {(x1, y1), (x2, y2), ... (xn, yn)} I need to obtain a linear function f from the broken line which connects all these points, so that I can the value of f at any point. I need to do this for two sets of points, i.e...

Hello, I have a problem with numerical solution of the system of ODE's (geodesic eqs.) in Mathematica. The only relevant command I have found is NDSolve. It works perfectly, unless my equations contain functions which are again computed using numerical methods. Simple example illustrating...

I use NMinimize to optimize a likelihood function. The number of parameters included depends on the dimensions of a vector I pass. I would like to have Mathematica check the dimensions of the vector, declare the correct number of parameters for me, and then solve for them. Right now, I have...

Mathematica: In[1]:= x = {(u + 2 v)/3, (u - v)/3, w}; D[x[u], u] Out[1]= {1/3, 1/3, 0}[u] + {(u + 2 v)/3, (u - v)/3, w}’[u] Why does it do this? Wolfram Alpha gives the answer I expected...

I want to produce a bifurcation diagram using mathematica to represent equilibrium points of p1 using the data obtained from the following code, where pn1, pn2, pn3 are recrusion exquations. i.e. x-axis will be the paramter t (ranging from 0-0.3) and y-axis will be the values of p1 this code...

Hi everybody. I have an impicit function that I want to solve numerically in mathematica it looks like: f[x] == b1 \!\( \*SubsuperscriptBox[\(\[Integral]\), \(0\), \(L\)]\(c[ x, \[Alpha]] f[\[Alpha]] SuperscriptBox[\(E\), \(-\( \*SubsuperscriptBox[\(\[Integral]\), \(0\)...

Hi, I was solving the following second order ODE: http://www.texify.com/img/%5CLARGE%5C%21x%5E2%20y%5E%27%27-5xy%5E%27%2B5y%3Dx%5E6%20sinx.gif I used variation of parameters and found this solution...

Homework Statement Graph in Mathematica to solve d^2theta/dt^2 + g/lsin(theta)= 0 Show a graph of period vs. Theta not. Homework Equations The Attempt at a Solution I am not very experienced with entering information into mathematica. I am aware that the manipulate plot...

Homework Statement A)Show that for a non-frictional, simple linear pendulum (Sin(theta) ~ theta) the total energy of the pendulum (K + U) or kinetic plus potential is given by E = (1/2) m l^2 (d(theta)/dt)^2 + (1/2) mgl (theta)^2 and therefor E = (1/2) mgl(theta0)^2 theta0 =...

Using the following code in mathematica: << DiscreteMath`Combinatorica` ShowGraph[TetrahedralGraph] Produces a regular Tetrahedral Graph. I would like to show data points on this tetrahedral graph with specific coordinates relating to the four points of the tetrahedron. Is this...

I have a plot of radius and temperature. I want to plot it in 3D by rotating it about the origin to produce a 3D plot. I can not figure out how to do this in Mathematica without doing it by hand and then plugging it into the Plot3D function. Any advice would be greatly appreciated. The...

Hi everyone. Hopefully this is easy to solve. I have large amounts of mined data that have differing levels of precision. I want to do analysis of: 1) number of decimal places present 2) significant figure error intervals based on the precision (for instance, 0.003 could have been...

What is Mathematica command for differential equation y''+2y'+5y=(sinx)*(e^x)?

I want to make a tetrahedron in mathematica. For example, suppose: {a = 0.2, b = 0.5, c = 0.1, d = 0.3} {a = 0.1, b = 0.2, c = 0.4, d = 0.3} {a = 0.4, b = 0.3, c = 0.2, d = 0.1} {a = 0.6, b = 0.2, c = 0.1, d = 0.1} and I want a tetrahedrom so that the four points are a, b, c and d -...

Good day to all, I am stuck with this. I am trying to construct a matrices with this properties... if n = 8, suppose the matrix with size 1 by 8 become [16 -16 16 -16 16 -16 16 -16] if n the matrix become [2n -2n 2n -2n 2n -2n 2n -2n ] with size 1 by n I do appreciate if someone...

i try run my program for NMinimize.it took a long time to solve.What is the problem of my coding?

edit: Forgot to add Mathematica in the title. Sorry! Hi everyone. I mined a lot of data and want to analyze it in Mathematica. The data is of the form {{x11, y11, x12, y11, x13, y13},{x21, y21, x22, y22}...} meaning that each set of x,y pairs is not necessarily the same size...

Hello, my name is Maciek, and I come write from Poland. I have big problem with Mathematica. The Program does not work. I can not put the coursor in a notebook, can not do any calculatins. Uninstall and install did not help. Mayby someone of You had simillar problem. Thank You for help!

Hi everyone. It's my first time posting in here. I have a mathematica notebook that defines a four-parameter prob density function (PDF). I define a likelihood function, import some data, and run a Nelder-Mead optimization strategy on the likelihood function using the data. My likelihood...