# Search results

1. ### Leas squares curve fit problem

The main problem is that I have no idea what I am doing. But second to that I am attempting to fit a curve to some data using the equation y = ((1/A(x-B)^(C+1))+D)^-1 if that makes sense I need to get the values for A,B,C and D and so have been looking into lsqnonlin but I am having...
2. ### Programs Wrong PhD?

Hi I'm doing a PhD in england and am worrying that I have gone into the wrong subject area(organic electronics), I only have a year left and feel like I can complete it but find myself drawn away from my subject area (i originally did a physics degree). What do you think I should do...
3. ### Anyone know the dielectric constant of OTS?

Anyone know the dielectric constant of OTS?
4. ### Column Flip Origin

Can anyoune tell me how you flip a column in origin so you are reading it from bottom to top? I don't mind if it means making a new column. Or if this isn't possible then is it possible to do a differential when taking the bottom values first?? If that makes any sense Thanks
5. ### Disoersion relation and lattice constants

Dispersion relation and lattice constants I need to be able to calculate the period (which I believe is the lattice constant) for a 1D crystal given the energy wavevector relation. Is this possible? I also have to find the Bravais lattice of a 2D crystal give a similar relation. What is it...
6. ### Gaussian fitting

I have a set of data for an absorption spectra that I plot the firtst derivative of and it gives me a gaussianish plot, I then want to fit it with a gaussian and what i've been doing so far is calculating the mean and variace of the spread and then using them in the equation. Although this does...
7. ### Srand() seed microsecs?

Hi Im using Visual basic c++ and was wonderig what the easiest way was to seed srand() with the time in microseconds is. Thanks
8. ### Add char to string class

hi, this is what ive got so far and what i'm wanting to do is add a char to the end(and eventually the beginning) of the string but i can't seem to get it to work, do you think ive got the right idea #include "string.h" #include <iostream> using namespace std; using namespace PC3762...
9. ### Converting a 4 argument class to int?

i was wondering whether it was possible to have a class say Vec4(i,j,,k,n) and then being able to assign it as an int eg/ Vec4 A(i,j,k,1) = 1; does this make any sense?
10. ### Hexagonal ice?

Hexagonal ice?? Has anyone ever modelled hexagonal ice Ih using c++ before?? Or has anyone got any tips on how to visualize the structure?
11. ### Drawing Molecules using openGL?

So far i've managed to draw a sort of diamond structure but i want to put spheres on some of the connecting vertices, put figuring out the angles and distances is quite tough, i was wondering whether there was any way of moving a sphere along a connecting vertex line directly. Any one any...
12. ### Haynes Shockley/Origin Pro

I've just completed an experiment using a laser to excite electons and hole in a germanium sample, and i want to fit a curve to some of the dat i've collected n origin, but i need to set up some initial parameters and i don't know how to work out what the origional number of injected holes...