Adjustment of curve: standard deviation given

Similar Questions

• How to get the standard deviation of parameter curve nonlinear

  Hello, I tried to understand (as here in the forum) how to obtain the standard deviation for the parameters of a nonlinear curve (Lev - Mar). The most interesting I found was on the Matrix of Covariance. Here the most reliable information came from DSPGuy (Message 8). But in the example VI it first takes the square root of the diagonal elements of the covariance matrix, and then multiplies these values with the RMSE (using the 'appropriateness' VI) to get the standard deviation of the parameters. In the thread, out of time, that it has been said that one has first to multiply the diagonal elements with the MSE directly from the Lev-Mar-VI.

  And another question is always there for me. That came in the previous mentioned thread:

  What is the DOF?

  a: N_MeasPoints - N_FittingParameters

  b: N_MeasPoints - (N_FittitngParameters - 1).

  If I understand the help for the 'appropriateness' VI a: must also be right, as the DSPGuy States. But I always thought that b: should suit like Peter Vijn2 said in the previously mentioned thread.

  Best thanks in advance

  Wolfgang

  Adding to the Christian post.

  1. If our documentation is incorrect, so let's fix it.

  2. I checked our source code for the CLN in the goodness of Fit.vi implements the DOF as our States to help.  They agree.  As the Christian States, if a different definition is appropriate for a given application, then you have the option to provide this value for the DOF.  I would add that the results that we return to the example related to the original message of Wolfgang tally with the results that the NIST certifies this problem to 8 decimal places.

  3 the form Christian mentioned, old implementation of Lev - Mar had an entry called "gap".  We have mapped to a weight using weight = (1/STD dev.) ^ 2 Christian to map the weight gap is therefore exactly what we used before.

  -Jim

• error of standard deviation

  I have a data set where all values are the same, but labivew is not a standard 0 deviation when I perform this calculation in a loop. Please see the .vi attatched. (Maybe I'm on something obvious).

  

  Computers cannot exactly represent numbers in floating point. The standard deviation, you have found is a small number, it is actually zero. You could easily test to see if it less than some others, very small number and set it to zero if you want.

• adjustment of curve with the equation

  I have a program in which I receive a response signal which is of the form A * cos (w * t) * exp(-t/T2), where A is the amplitude, w is frequency, t is time, and T2 is the spin relaxation time. Is it possible to adjust a curve in this graph and output the values of the variables? I have tried many options in labview but can't seem to find a way to add the variable T2.

  Thank you

  Justin

  LV8.6

• FPGA - windowed moving average, variance, standard deviation, kurtosis and asymmetry

  Hello!

  I'm processing in FPGA and I want to calculate the MOVING WINDOW average, variance, standard deviation, kurtosis, asymmetry online for the last N (N is the size of windows) elements. The frequency is about 100 kHz and N about 10000 (100 ms of signal).

  I found something like EMA (moving average exponential)...

  Have someone solved something like that? Any ideas how to fix?

  That looks like a problem. What type of window you need? The moving average exponential isn't an option? There are online algorithms described in Wikipedia, but they can suffer from problems of numerical accuracy when it is implemented in a fixed point (depending on the nature of the data). They would be interesting watch in, however.

  Other than that, here are some options that I can think of:

  • More large FPGA
  • Be part of the treatment on the RT controller - have - you looked into that?
  • Return to your needs and push some of the numbers. Do you really need 100 ms in all cases, etc.?
  • Depending on the nature of the data, simple compression techniques may be an option
  • An precision analysis to determine the data type minimum, that you really need. For example, getting to 25 bits, would have a huge impact on your cost of multiplier.
  • Consider the mathematics of floating (using Xilinx IP cores) point to online methods. Your flow is relatively low, so you could share it resources between all channels. Manage States of different channels is complicated but is doable.

  The BRAM will be used for FIFO buffers, but is also available for general use to implement the fifo and memories. Some IP use BRAM under the hood, keep an eye on the compilation summaries to monitor how much still you have.

• How to calculate the standard deviation of a certain number of points?

  Hi, I have a request that I acquire signals of strength and Pu, then on a table.

  I need to calculate the standard deviation and the mean each a number of points, 1000 for example.

  I have problems with this, if you can help me I would be grateful.

  Thank you

  Douglas

  If you need something like this?

  

• standard deviation for the slope of the linear fit

  I need away from the slope of the linear fit.

  Please confirm me if what I do is correct.

  I use the 'delta slope '' of the linear intervals did change the trust level of 0.95 to 0.68.

  But again, I'm not sure I can identify the slope delta as the deviation of the slope.

  Thank you

  Hello

  I did some research more.

  As I understand it, slope delta (or radius of trust) can also be referred to as margin for error.

  You may need to do more research on your own in this regard, but it seems that the two are different types of analysis. Standard deviation is a measure of the variability of a set of data, while the slope delta (or margin of error) refers to the amount of random sampling error. If you can get a direct link between the two, I'm not sure, however the first link below indicates that this is possible.

  http://stattrek.com/AP-statistics-4/margin-of-error.aspx?tutorial=AP

  http://en.Wikipedia.org/wiki/Standard_deviation

  http://en.Wikipedia.org/wiki/Confidence_interval

  http://en.Wikipedia.org/wiki/Margin_of_error

  I hope this gives some more.

  Regarding the algorithm we use in the interval linear form VI, I think that the following document would be a good start.  There is a section called "confidence interval and interval of forecasting."    It describes the algorithm we use.

  I hope this helps!

  Bye,.

  Licia

• Smartphones blackBerry re - adjust the curve?

  Just got a storm and I sell my curve to a friend.  How can I re - adjust the curve to wipe all the lists, contacts, history, etc. ?

  Thank you

  Options of > Security > General settings > press the menu key and select Delete Handheld.

• need a script to custom calculation to calculate the standard deviation

  need a calculation script customized to calculate the standard deviation of 8 rows, it is a form .pdf variable data entry points will be users using this model as a form.

  I can get the average of simple calculation, but struggling with the script for the standard deviation. Any help would be appreciated.

  Header 1	Header 2	Header 3	Header 4	Header 5	Heading 6	Heading 7	8 header	Header 9	Header 11
  sample1Row1	sample2Row1	sample3Row1	sample4Row1	sample5Row1	sample6Row1	sample7Row1	sample8Row1	Average	stdDeviation

  If the formula is not:

  StdDev = sqrt (sum (sampleXRow1 - average) ^ 2 / (n-1))

  But:

  StdDev = sqrt (sum ((sampleXRow1-average) ^ 2) / (n-1))

  If the code should be something like this:

  var avg = Number(this.getField("AverageRow1").valueAsString);
  var sum = 0;
  var n = 0;
  for (var i=1; i<=8; i++) {
      var v = this.getField("sample"+i+"Row1").valueAsString;
      if (v!="") {
          sum+=Math.pow((Number(v)-avg),2);
          n++;
      }
  }
  if (n==0 || n==1) event.value = "";
  else event.value = Math.sqrt(sum / (n-1));
  

• calculate the standard deviation

  Hello

  as a pdf, I want to calculate the standard deviation of 5 named fields (F1, F2, F3, F4, F5) which is digital and I think that this can be done through a... custom calculation script can you help me please a code for this calculation...

  Thank you

  Here is a link that is tested in the fall zone file. You do not need to join, just click "continue to display" and download the form to use the form.

  Calculate the standard deviation

• Samplers colour - dark, clear & grey point - how to adjust the curves

  Hi all

  I set myself dark, light & gray point in an image. Ask yourself how to adjust the curves based on the color samplers. I manually call the dialog box curve and select the dark feather and choose sampler no1, select cast and select no2 sampler, select gray feather and choose sampler no3. No idea how this can be done in the script?

  OK, I see one of the problems, and you noticed yourself, you just did not understand what is happening.  When using the pipettes in the curves Panel it does not matter if you use the black or white pipette first. You can set the white point and black point or reverse that order and you get the same curve. What is important is when you use the grey eyedropper. That should be used when both the white and black point has been resolved. If you set gray in the Middle, he gets thrown when you set the last point and you get the same curve, if you simply ignored the gray point total. In other words, if you do not set the last gray point said you in effect it at all.

  Notice in your video when you click on the sampler on the neck that the image is very cyan. It is only when you click the last sampler that color refers to something more normal. You can see the same thing in looking at just the curves. By clicking on the neck creates curves with long arcs. By clicking on the last sampler transformed into lines between the white and black point (because the gray point is deleted)

  Which brings back us to where the sampler are placed make a big difference. Skin tone is not when you want to set the gray point. I think you are using the mask of the luminance to calm the adjustment because the black and white points are also misplaced. The color of the blackhead is within 20 years. I think a better place would be under the jaw on the right side of the neck. Indeed, this region is already 0,0,0 so I would not put a black dot. The white Sampler is in 230 years. Parameter to white clips many of the wall at the top left.

• How do Control M to create an adjustment layer curves?

  M control creates a default curves adjustment.  However, there is a way to get control M to create a curves adjustment layer.  I forgot how to do this!

  Go to Edition > shortcuts keyboard and change the Ctrl + M to layer > new adjustment layer > curves.

• Aggregator customized to calculate the standard deviation

  Hello
  This is probably already available or easy to implement, but I find it difficult to find samples for writing a custom aggregation and ParallelAwareAggregator.
  
  I'm figuring the difference type of a variable in my item being cached in a real-time system. I want to aggregate the result sum [(X-X') ^ 2] where I spend X' (average) of the client. Can someone help me with an example?
  
  Thank you
  Sairam

  Hi Sairam,

  in fact, you probably have better use the single-pass approach to calculate the standard deviation, as the average of the values may change before you calculate the number of entries and the average gap.

  You can use the following formula to calculate the standard deviation in one pass: sqrt (N * sum (sqr (Xi)) - sqr (sum (Xi))) / N, where the sqr function is the square of a value, the square root function is the square root of the value, N is the number of entries and Xi is the value to calculate the gap type from the entry of the i - th.

  You can do something like this:

  public static class StdDeviation implements ParallelAwareAggregator {
  
    public static class PartialResult implements Serializable {
  
        private long numberOfElements;
        private BigDecimal sum;
        private BigDecimal sumSquare;
  
        public PartialResult(long numberOfElements, BigDecimal sum, BigDecimal sumSquare) {
            this.numberOfElements = numberOfElements;
            this.sum = sum;
            this.sumSquare = sumSquare;
        }
    }
  
    public static class ParallelPart extends StdDeviation implements EntryAggregator {
  
       private ParallelPart(ValueExtractor extractor) {
          super(extractor);
       }
    }
  
    private ValueExtractor extractor;
  
    private transient boolean notParallel;
  
    public StdDeviation(ValueExtractor extractor) {
      this.extractor = extractor;
      this.notParallel = true;
    }
  
    public Object aggregate(Set entries) {
       ValueExtractor extractor = this.extractor;
       BigDecimal sum = 0;
       BigDecimal sumSquare = 0;
       long num = 0;
       for (InvocableMap.Entry entry : (Set) partialResults) {
          sum = sum.add(partialResult.sum);
          sumSquare = sumSquare.add(partialResult.sumSquare);
          num += partialResult.numberOfElements;
       }
  
       return calculateStdDeviation(num, sum, sumSquare);
    }
  
    public EntryAggregator getParallelAggregator() {
  
       // you could return this, instead of ParallelPart
       //
       // return this;
  
       return new ParallelPart(extractor);
    }
  
    private static Number calculateStdDeviation(long num, BigDecimal sum, BigDecimal sumSquare) {
       BigDecimal partRes = sumSquare.multiply(new BigDecimal(num)).subtract(sum.multiply(sum));
  
       // you can replace the square rooting of a double value with a proper implementation of square root for BigDecimals,
       // which I omitted for the sake of brevity, and then you can do BigDecimal division (make sure you provide a MathContext)
       return Math.sqrt(partRes.doubleValue())/num;
    }
  
    public static Number execute(NamedCache cache, ValueExtractor extractor) {
       return (Number) cache.aggregateAll(AlwaysFilter.INSTANCE, new StdDeviation(extractor));
    }
  }
  

  There is actually no reason for the class ParallelPart to exist. I put it here to illustrate that there can be a different aggregator instance to the ParallelAware aggregator optimized to run on the side of the storage, but you could just "this" return of the getParallelAggregator() method, it wouldn't make a difference for this implementation of the aggregator.

  You can replace the rooting square a double value with a good implementation of the square root of BigDecimals, which I omitted for brevity, and then you can make division BigDecimal (make sure that you provide a MathContext)

  I also omitted the ExternalizableLite and PortableObject implementations (and necessary parameterless constructors) for brevity of the ParallelPart and PartialResult classes.

  In addition, you may need some mojo if you want to use a PofExtractor instead of a regular Value Extractor to avoid the deserialization of the cached value.

  You can perform the aggregation with the execute method, passing the cache altogether on the Extractor which extracts the value as a BigDecimal value cached.

  Best regards

  Robert

  Published by: robvarga on March 12, 2010 11:36

  Published by: robvarga on March 12, 2010 11:43

• Adjustment of curve using Levenberg-Marquardt algorithm

  Hi all

  Thank you for my request answered in the last post. One thing I like about Labview is its ability to allow complex models to be fitted to experimental data with so much ease. I have been using the L - M unconstrained editing for some time. However, there is a question to which I thought I would like to be answered by Labview professional themselves.

  When the curve adjustment is completed, the algorithm always has the minimum value for a reverse parameter. for example. Suppose that a parameter X is found to have a value of 0.8 after editing by l.-m. algorithm. However in principle several orders of values are possible for x. for example is not a sensitive parameter in the main equation so it can have values of 1000 or 400, or 60, 1. In this scenario the algorithm will always give an answer like X = 1; This is the minimum solution?

  See you soon,.

  Navneet

  Navneet,

  Implementation of Lev - Mar in LabVIEW does not explicitly attempt to diminish the importance of any parameter.  If the parameter has as little impact on the distance between the data and the best curve fit, then it will change according to the gradient of the problem.  If the parameter does not affect the distance, so that you can get a linear solver error indicating a deficiency in a row.

  You can detect this behavior by using the Intervals.vi to mount curve nonlinear.  An interval that is very large compared to the other parameters would indicate a low dependence on this setting.

  -Jim

• adjustment layer curves not affecting does not image

  Hi, I have a photoshop image strangely uncooperative. I put a curve on adjustment layer to increase the contrast [file monolayer] and has no effect. What could happen?

  If you want to see it, the file in question is here: http://x.co/67Ae8

  Thank you. [2.5 GHz, 10.6.8 imac. [ btw, version of photoshop is CS6.]

  Well Yes, looks like no change for me.  Rbin was right, and he would do because if it's just different layers opacity to black that the curves would not affect him.  Just stick a white fill on the background layer.  The curves layer will adjust the combination of the two layers, which gives him the gray to work with.   Seems to work fine for me now.