Interpolation Definition and 136 Threads

  1. L

    Interpolation of data on Excel for analysis of Load Displacement

    I don't need any help for the engineering maths I'll be doing after but if I anyone could advise me on how to write a program that would take a set of x and y values and then give me back the y values at certain intervals on the x-axis I would be very grateful. I've got colossal amounts of data...
  2. C

    Thermodynamics, Linear Interpolation

    Homework Statement I have been trying to learn how to use linear interpolation to find out the data needed from the thermodynamics chart, however, the book that is assigned does not even talk about it. Could someone please explain how linear interpolation is used? Thanks
  3. M

    MATLAB Matlab interpolation for 3 axis data

    Hi, I'm doing a project in medicine, I've used MATLAB to create 3d graphs using a vector with 5 fixed values as X, a vector with 7 fixed values as Y. As Z I have 5*7 measured values. I need to interpolate my graph to "smoothen" the lines in the graph, but I am totaly lost, I have no idea how...
  4. D

    Quadratic Interpolation & 2nd Order Diff. Equations

    For a second order differential equation, is it necessary to derive a weak form if quadratic interpolation are used?
  5. N

    How Can Lagrange Interpolation Be Implemented in Software Development?

    Basically I've got to design and develop a software for computing a polynomial function involving a set of data points. I've got to use an algorithm based on the lagrange interpolation method. I know it should involve two loops inside the code. What I've been told is that "The input to the...
  6. S

    Interpolation Formula in MATLAB | Solving for y(ti) with Code Example

    Homework Statement If i have an interpolation formula, say: y(t_i)=3+h\sum^i_{j=1}jy(t_j) where i=0 to n h=(a+b)/n ti=i*h and when i=0, we have: y(t0)=0. How would i write a code to find y(ti)? Homework Equations The Attempt at a Solution function y=examp(a,b,n)...
  7. P

    Non-uniform bi-linear interpolation

    I have a non-uniform grid within which velocity data is known at each grid point. This velocity data is to be interpolated to allow for evaluation of velocity at an arbitrary point inside the grid. I am wondering about the correct approach to this problem. In actuality I want to evaluate the...
  8. B

    Linear interpolation of a sine wavetable

    Hi everyone. I'm doing a microcontroller project where I'm using a 256 element array of 1 byte values to output a sine wave at varying frequencies. I'm using the top 8 bytes of a 16 bit "angle increment" value that's incremented by varying amounts as an index to the array of values, to control...
  9. T

    Interpolation methods for two points and three derivates?

    Hi everyone, I have a question about interpolation methods. I am given two particles and I know their positions, velocities, accelerations, and jerks (time derivative of acceleration) at some initial and final time-values (t0 and t1, respectively). I want to find the minimum distance...
  10. O

    Solving Cubic Spline Interpolation with Conditions and Coefficients

    Homework Statement Consider the use of cubic splines to interpolate a set of data. Suppose at some stage in the calculation we arrive at the following spline functions for two consecutive intervals \tilde{f_{0}} = x^{3} + ax^{2} + bx + c over the interval -1 \leq x \leq 1 \tilde{f_{1}} =...
  11. B

    MATLAB Interpolation Methods in MatLab for Plotting Car Fender Coordinates

    Hello, I'm having a really hard time doing some work in Matlab, I have a book but it just isn't making sense to me, the problem I have to do is in four parts so Ill just show the first part for now... The following coordinates specify the shape of a certain cars’ front fender. Interpolate...
  12. S

    Calculate Overflow Rate w/ Interpolation: BOD Removal 80%

    Interpolation ? A treatment plant consists of a primary sedimentation tank followed by a trickling filter that removes 80% of the influent BOD. The flow is then directed to a constructed marsh system that has an influent target BOD concentration of 30 mg/l before being discharged to a small...
  13. S

    What is the degree of the interpolating polynomial?

    Homework Statement Given points (x0,y0), (x1, y1)...(xn,yn) and derivatives at each of these points y'0, y'1...y'n : Write a program to find the interpolating polynomial (of degree 2n+1) and to evaluate it on given points xeval. My question is what type of interpolation is this? I'm not...
  14. B

    Simplifying 'b2' of Newton's divided difference interpolation

    Hi all, http://www.bsodmike.com/stuff/interpolation.pdf" I am going through some of my notes and quite a few books; they all skip the over the point I have marked with 3 red dots in the http://www.bsodmike.com/stuff/interpolation.pdf" . \begin{equation}\label{eq:solution}\begin{split}...
  15. D

    Quadratic Interpolation question

    I have to find a system of linear equations to determine a quadratic polynomial p(x) = ax2+bx+c Given the conditions: p(1) = f(1) p'(1) = f'(1) p''(1) = f''(1) where f(x) = xex-1 I know: p(x) = ax2+bx+c p'(x) = 2ax +b p''(x) = 2x f(x) = xex-1 f'(x) = ex-1 +...
  16. S

    Interpolation between two surface meshes

    Hi, I've been given a problem to solve and I was hoping for some pointers. To start with we have a surface which is originally represented as a Bezier patch, a peicewise set of bi-cubic bezier surfaces. It might be important to mention that the surface is "fairly two dimensional", the surface...
  17. U

    Mathematica Give to an interpolation function an analitic function with mathematica

    i have solved a differential equation with shooting methods, the output is in form of interpolate function, i can see it with a graphics, but i i would have an approssimate analitic form what kind of function i have to do ? the equation give in output have this form...
  18. U

    MATLAB Using quadratic interpolation in matlab how ?

    http://img337.imageshack.us/img337/8922/problemcmi0.jpg Can anyone explain to me please how this problem is solved ?
  19. D

    Solving Newton interpolation with c

    Hi, i have no idea how to start up my program on Newton interpolation. i have solved it manually but I am clueless on how 2 start my program. below represnts the input which i want 2 solve. every 4 lines represnts one problem. the 1st line- n,m where n is no of data points and m is no of...
  20. A

    Newton's Interpolation, numerical methods question

    Can anyone tell me what is the equation for First Order of Newton’s Interpolation? The one of Interpolation I know is Lagrange’s Interpolation such as p(x)= \frac {x-x1}{x0-x1} f(x0) + \frac {x-x0}{x1-x0} f(x1) and so on ... Thanks in advance
  21. H

    Cubic Spline Interpolation Tutorial

    Attached below are two cubic spline tutorials: 1. Explanation of the classic tri-diagonal cubic spline formulation. Included are 2 example problems. 2. Extension to parametric cubic splines. Included are 2 example problems . :smile:
  22. A

    Interpolation using divided differences

    Homework Statement Given a set of data points, derive the interpolation polynomial using divided differences. Homework Equations The Attempt at a Solution My main question is: How am I supposed to do this if they don't give f(x)? Can I just look at the plotted data points and...
  23. A

    Proving Interpolation of L^p Spaces: How Do You Find the Right Inequality?

    Homework Statement If 0 < \alpha < n, define an operator T_{\alpha} on function on \mathbb{R}^n by T_{\alpha}f(x) = \int |x-y|^{-\alpha}f(y)dy Then prove that T_{\alpha} is weak type (1,(n-\alpha )^{-1}) and strong type (p,r) with respect to Lebesgue measure on \mathbb{R}^n, where 1 < p <...
  24. U

    How do I quickly and easily interpolate a point on a chart without given data?

    I completely forgot how to do this. I have a thermo test coming up and i will be interpolating a lot of data. What is the fastes/easiest way to interpolate a point on a chart not given?
  25. C

    Finding refractive index by interpolation

    The problem is described here: http://phstudy.technion.ac.il/~wn117066/Problems2.pdf In question 1 I need to find the refractive indices for both polarizations at 760nm. I'm not quite sure how to go about this - which model of dispersion best fits Calomel? (I'm done with the exercise...
  26. C

    Question about Smooth Interpolation

    any thoughts to this question? Give an example of a C^oo (C infinity) function f : R->R which is positive on the interval (-1, 1) and 0 elsewhere
  27. S

    Interpolation and Extrapolation

    Hi, I've a table of data in the following format: x--> 0.1 3.767 4.395 5.0223 y 0.1 | 1 1.5 2.0 2.0---->z 0.6764 | 1 2.0 2.2 3.599-->z 1.10146 | 2 2.2 2.5 3.686-->z 1.3855 | 2.5...
  28. C

    Linear Interpolation to Find Z Value in Quadrilateral

    I have a problem where I need to work out a value of a specific point that lies in the quadrilateral that is formed by four separate points. For each point that makes up the quadrilateral, I know the X and Y coordinates and their value, Z. For the point I am trying to find the value for, I only...
  29. J

    Calculate an error bound of this interpolation value

    I attached the file. I am up to 1(c). Would the error bound of the interpolation value just be taylor series error term? Thanks
  30. A

    Lagrange interpolation polynomial

    Hello everyone Here is my problem lagrange interpolation polynomial across the points([SIZE="5"]x0,[SIZE="5"]y0),([SIZE="5"]x1,[SIZE="5"]y1) and ([SIZE="5"]x2,[SIZE="5"]y2) is given by [SIZE="5"]y[SIZE="1"]0[SIZE="5"]L[SIZE="1"]0([SIZE="5"]x) +...
  31. L

    C/C++ Lagrange Interpolation: Investigating Interpolation Points with C++/Fortran

    In my comp physics class, we've been introduced to both c++ and fortran languages. For instance, for our first assignment, I am not sure how to go about investigating the quality of interpolation points for i.e f(x)=sin(x^2) by using n-point langrange interpolation, where n is an input...
  32. B

    Why Use Interpolation Over Extrapolation for Calibration Curves?

    Could someone help me understand why interpolation rather than extrapolation should be used for calibration curves (with the exception of Standard additions). I know that extrapolation is less precise, but the book I've got doesn't over any more than that, and I think I need a little more detail...
  33. Dissident Dan

    Interpolation Axis for two Matrices

    If you have two standard 3d, orthogonal matrices representing axes of 3d coordinate systems of the same handedness, is it possible to find the vector about which you would rotate one of the matrices to get the other? If so, this would be a lot more intuitive than quaternions (at least for me)...
  34. L

    Solving Linear Interpolation for 3-D Triangle Edges

    I have a 3-D traingle, and the edges are a,b,c. If I want to find a line interpolation at a point in the center, let's say that it's P(x,y)... My equations are \Delta Z = A + Bx + Cy \Delta Z_a = A + Bx_a + Cy_a \Delta Z_b = A + Bx_b + Cy_b \Delta Z_c = A + Bx_c + Cy_c In order to...
  35. M

    What is median by interpolation and how can it help me find the median?

    I was doing some last minute skimming through my book for my exam tomorrow and panic. Can someone please please tell me about finding the median by interpolation and perhaps an example of how it would could used or asked, i will be forever greatful :cool: yasmin x (i can only find a...
  36. K

    How can interpolation be used to find a polynomial formula for G(n)?

    Find a formula to calculate G(n) and it should be a polynomial of degree 4. G(n) = 1/6(0)(0-1)(0-2) + 1/6(1)(1-1)(1-2)+...+1/6(n-1)(n-2)(n-3) I know G(0)=G(1)=G(2)=G(3)=0 G(4)=1 G(5)=1+3 G(6)=1+3+6 G(7)=1+2+3+10 G(8)=1+3+6+10+15 (sum of triangle numbers) What should I do to...
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