Polynomial

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• Polynomial function

  First of all, thanks to you in advance for reading my question and taking the time to respond. I greatly appreciate your effort.

  I have 30 lines of data. Each line represents the net amount of items sold every day.

  I created a graph 2D with these data and applied the polynomial regression for purposes of sales forecast. You can find this feature under series->-> polynomial trendlines.

  You also have the following options to order: 2, 3, 4, 5 and 6 (I chose 6). That really means this 'order'?

  Very simplified and general answer (from a non-statisticien):

  Trend curves are the "best fit" lines applied to a set of XY data that has been drawn on a diagram of dispersion. A linear trendline can be described using a polynomial function "order 1':

  y = a * x ^1 + b * x ^ 0

  (x ^ 1 = x, x ^ 0 = 1)

  Best suited for data graphics in a shape that looks like a curve will require a graphic that function as a curve, as a quadratic function (order 2):

  y = a * x ^2 + b * x ^ 1 + c * x ^ 0

  Data sites that seem to have a folding alternated in the curve, you need a higher order, such as a cubic function (order 3)

  y = a * x ^3 + b * x ^ 2 + c * x ^ 1 + d * x ^ 0

  Unless your data set is large enough, higher orders probably will not give you a more precise match.

  For more information, search for "polynomial regression function" and check out some of the statistics pages.

  Kind regards

  Barry

• First - Division of polynomial

  Quick questions, hoping someone can explain.

  I want to do first HP (2 x ^ 2 + x + 6) /(x+1)

  When I enter quot(2x^2+x+6,x+1) I get 2 x-1, but he neglects to tell me about the rest of (7 / x + 1) is this nbehaviour expected? How can I get a complete result?

  Thanks in advance

  Paul

  Hi, Paul!

  Functions of the polynomial division:

  quot - quotient only.

  REM - rest only.

  quorem - the quotient and the remainder.

  Hope that helps!

• How to calculate the equation of dataset using 'Fitting VI' (non-linear or polynomial fit)?

  I have the datasheet of a NTC (thermistor negative Coefficient) and I want to calculate the most approximate equation

  that describes its behavior. The table has values of temperature and resistance. If the resistance of the NTC varies according to the temperature it detects. I tried the following:

  -Excel: polynomial adjustment

  -Maple: polynomial adjustment

  -LabVIEW: Polynomial Fit.vi

  I've been doing equations with a not very good approximate parameteres. I suspect that this method 'Polynomial FIT' it is not the best method for this type of data/equation (being a non-linear equation).

  So is - that someone has used the non-linear Fit.vi matching the behavior of a dataset object? If so, can you explain how this VI... I would really appreciate it.

  Thanks in advance and I will wait for your reply.

  
  

• assessment polynomial vi giving inconsistent results

  I'm looking at an easier method to evaluate polynomial, rather than using formulas nodes that I currently use.  I found the "polynomial evaluation vi' who would think based on aid would be able to calculate the result of a polynomial Exhibitor multi.

  Currently, I would do something like the following in a node of the formula:

  float64 D1 = 0.387481063640E - 01;
  float64 D2 = 0.332922278800E - 04;
  float64 D3 = 0.206182434040E - 06;
  float64 D4 = - 0.218822568460E - 08.
  float64 D5 = 0.109968809280E - 10;
  float64 D6 = - 0.308157587720E - 13;
  float64 D7 = 0.454791352900E - 16;
  float64 D8 = - 0.275129016730E - 19;

  DC = (V * D1) +(D2*V**2) +(D3*V**3) +(D4*V**4) +(D5*V**5) +(D6*V**6) +(D7*V**7) +(D8*V**8).

  I tried the same calculation by writing a little VI which used the polymomial assessment vi and get seriously incorrect results.  (my vi attached).

  Research in the evaluation of the polynomial vi, honestly, I don't know how it is supposed to work, unless he's trying to do something completely different that I do.   (With the help of labview 2015)

  I'm open to suggestions here.  Thank you!  Mitch

  The first table is the constant term (V ^ 0 = 1), if you need to add an element that is equal to zero in the table of coefficients.

  The polynomial is defined as:

  DC = D0 + (V * D1) +(D2*V**2) +(D3*V**3) +(D4*V**4) +(D5*V**5) +(D6*V**6) +(D7*V**7) +(D8*V**8)

  In your case, D0 = 0, but there still need to be there.

  

  ... and are not the constant diagram EXT. As you can see about to constraint, it will be converted in any case to DBL.

• Feature Request: order more polynomial scaling

  VeriStand supports up to 9, and the producers that I am simulating are settled with polynomials of order 10. I'm getting 9 on the curve the 10 makes it and get on with it, but it would be nice if it wasn't an arbitrary limit.

  Hey Stephen,

  This definitely falls into the territory of feature request, but it seems that the scale supports an arbitrary number of coefficients.  It's just the system explore UI that limit us.

  To test this, I went directly in the XML definition of system and a factor of 11 has added to the scale of the polynomial:

  

  And it seems to work to generate the reverse and actually coefficients across the channels.

  Note: in general, it is never recommended to amend the definition of XML system directly.  You could cause unforeseen problems and generally make your life difficult.  Using the ZFS API to create a polynomial scale would be the recommended method to work around this limitation of the user interface.

  -Kyle

• Polynomial evaluation in FPGA

  Hi all
  I am currently facing a problem. I want to evaluate a 6 order polynom in the FPGA (in fact this function will be part of a larger VI). Here's what I put in place:
  Coef tab contains 7 following coefficients (from the RT):

  2734.91

  53.4378

  -2.02666

  0.0463295

  -0.000588338

  3.71736e - 06

  -9.06681e - 09

  When I sent this VI in the 2013 worker compile, I get the following error:

  LabVIEW FPGA: Compilation failed due to the overmapping of the resource.

  The FPGA VI does not fit on the FPGA target because the VI requires more resources
  that are available.

  Suggestions to eliminate the problem:
  Reduce the amount of logic in the VI
  Reduce the number of multiplications, FIFO, or the amount of memory on the block diagram
  Reduce the number of objects on the front panel
  Change the settings of the arbitration
  * Use Timed loops instead of other loops
  * Use Timed loops for intensive resources sections of the block diagram that
  do not require a loop

  I don't know how to solve this problem... Any idea?

  Thank you very much!
  Tom

  What happens if you did it in a loop For?  Two registers, one to accumulate the multiplications of the value of X, the other to accumulate the polynomial to offset additions.

• Primitive polynomial (generate some Bits VI)

  In the attached VI, I'm actually generate bits using the PN sequence and primitive polynomial. I'm having a problem in the primitive polynomial. If I have a primitive polynomial (x ^ 4 + x + 1) can any body guide me how to make it work? I tried different ways but error message.

  Thank you

  JK

  I fixed it my self.

  Thank you

• CRC-16 with 0 x 8005 polynomial

  I use a CRC-16 for a community page VI of NOR who uses 0xA001, which is the inverse of the polynomial, I want to use, 0 x 8005. For example, with a single 0xD6 byte data, the CRC-16 with 0xA001 is 0xDE3E, it should be 0x9E81 using polynomial 0 x 8005. Change just the polynomial does not give the right result. I have an attached image. Is there something I should 'flip', or 'reverse' to be able to use the polynomial I want and get the right answer?

  

  
  

• Multiplying by output of small polynomial coefficients on vi trendline and get unexpected results

  I'd appreciate it if someone could shine any light on this problem for me.

  I'm performing a polynomial regression with the VI express Curve Fitting.  The express VI itself works very well.  I used the polynomials it generates for the graph of a function in Excel and it looks perfect.

  When I convert the signal to an array and then multiply by other values things start to go south.

  The results of multiplications are wrong when some 'x' values are used.  The strange thing for me, is that it does not work for all values of x.

  Not sure if this is useful, but the expected values for x 0 through x 5 (bottom right, below) are:

  x 0:-1,14

  x 1: 16.11

  x 2:6-3-19

  x 3:-3.39E - 4

  x 4: 6.76E - 7

  X 5:-2.08e - 7

  and the values displayed when the routine is running:

  x 0:-1,14

  x 1: 16.11

  x 2: 25.57

  x 3:-925.06

  x 4: 104.25

  x 5:-2017.87

  Any ideas?  I think a data type must be changed since the expected values are very small and the problem is only present for certain values of x.

  If this is the case I don't know how to change the data type.  The table contains double the conversion of the shape of the signal.

  Thanks for any help,

  Dave

  

  Hi TCPlomp,

  I just realized that I had x and is reversed in my entries "power x" function.

  Thanks for letting me know about polynomial screws.  Add those who should be more pleasant than to try to clean it.

  Kind regards

  Dave

• How to solve polynomial roots using MathScript

  I understand the examples use the roots.vi to solve 0 = Ax ^ 2 + Bx + C for the roots of the polynomial when the coeficients are known...

  But how to find the roots of the polynomials for 0 = Ax ^ y + Bx + C where y =. 625, for example?  Ideally, I would like to do this in matscript which I already use.

  I hope that this is a trivial question, but I'm over my head!

  Thanks in advance!

  
  

• How to find the crest of a curve of best polynomial form

  Hello

  I'm relatively new to Labview.  I need to find the value of x corresponding to the maximum value of a better curve adjusted to a set of values there.

  A typical dataset that I will work with is a table of about 15-30 y-values that are equal distance from known x-values (I have attached a file .lvm for an example of values y and x values), and it will be a fairly well-defined Summit.

  The way that I do currently is to use the curve express vi, with a polynomial curve of 10 order, and then by converting the best adjustment line to an array of values using array Max vi Index to find the peak value y and wiring its index in a table of x values to find the position corresponding to the peak. I enclose my vi that does this.

  The problem with this method is that I can't get the accuracy I need (because the values of x are spaced by 0.15, I wish that the precision of about 0.01).

  I also tried out the best integrate a node formula coefficients (from the curve express vi) and then run a loop of x than aircraft values more accurate data points, but I had trouble getting the curve of this method to match the better to express vi curve curve.

  Do you have any suggestions?

  Call it what you want, but you're smoothing or filtering your data.  It will pass the height and location of your apparent peak.  Instead of trying to fit all of the data, you must use a mobile window where you set a subset of the points to a polynomial and check for a pic.  That's exactly what the Ridge detector VI.  I'd like to see if this VI - what are looking for before you go through the gymnastics of the polynomial.  In my example, I remove the maximum amplitude peak and find its location.  The location returned by the peak detector is a fractional index, so you can use interpolation 1 table D to find the corresponding x position.  If you stay with the polynomial in the form, discover all of the polynomials screws, they are a snap to find the zeros of the derivative and other.

  

  BTW, unless you really know the underlying model for your data I personally would be questionable estimates of precision that are 1/15th of the point spacing. 1/3 or 0.05 he pushes IMO.

  Edit: 1 K apparently.

• accuracy of polynomial roots

  Hi all

  Does anyone know the accuracy of the polynomial root function

  up to how many decimal places can I be sure of the result of the root?

  Best regards

  Tinnitus

  
  

• General polynomial fitting of a curve at 5 points

  Hi, I'm trying to adjust a curve of only 5 points with the polynomial general function, but it doesn't seem to work. I tried all the algorithms and controls up to 5 (number of points). You have a solution for that wonderfull should be that we get with excel?

  

  I think you're using the coefficients in the wrong order. If the coefficient is a, the formula is:

  y = a0 + a1 * x + a2 * x ^ 2 +...

  Or as you label, element 0 is e, item 1 is d...

  Hope this helps,

  Daniel

• Polynomial to scatter

  Hi all

  I was wondering if there is a way to generate a polynomial fit to a diagram of dispersion as in excel. Data that I'm trying to adapt have several values of y for each value of x.

  Thank you

  Krish

  You must sort the data by X. Here's how it could be done. See if it works for you. (currently you try to adjust the data which zigzags in the plot area.)