[MATH] Re: Where are the multivariate vector optimization options that are non-deprecated?

On Thu, Oct 1, 2015 at 4:07 PM, Gilles wrote: > On Thu, 1 Oct 2015 15:40:24 -0700 (PDT), Rebecca2w2 wrote: > >> Hey, I'm new so maybe I'm missing something, but here we go. >> > > The first thing you have missed[1] is that posts' subject line should > be prefixed

Re: [math] Poisson distribution to show how many ambulances are dispatched per hour

David, The Poisson distribution tells you things like the probability of different numbers of ambulances being dispatched. For simulation purposes, it is usually far preferable to use the exponential distribution to compute the time of the next ambulance. In R, computing 100 dispatch times

Re: [VFS] Could the HDFS connector work with MapR systems?

The NFS mount trick allows all of the files to appear via the local://* file system. Otherwise, it is true that the wire protocol for MapR FS is different from HDFS. In fact, the wire protocol for different versions of HDFS are different as well. But what is standard is how different

Re: Correlation coefficient

On Mon, Aug 18, 2014 at 1:15 AM, Bobic, Tamara tamara.bo...@hpi.de wrote: However, I realized that I should be using a special variant of Pearson if one of the variables is nominal - Point Biserial correlation coefficient. Doesn't this just work if you build a surrogate for the dichotomous

Re: [math] Curve fitting ...

Have you considered using an interactive system like R, Matlab or Octave? You might be happier. Or even have you considered goal search in Excel? On Wed, Aug 13, 2014 at 6:08 PM, South Light southligh...@gmail.com wrote: Hi, May be someone can help me with this problem. Given the

Re: [math] Calculating gain matrix in KalmanFilter

Arne, I think you are correct. On Mon, Aug 4, 2014 at 7:34 AM, Arne Schwarz schwarz.a...@gmail.com wrote: 2014-08-04 13:43 GMT+02:00 Gilles gil...@harfang.homelinux.org: On Sun, 3 Aug 2014 18:18:24 +0200, Arne Schwarz wrote: Hi, I saw that to calculate the gain matrix the actual

Re: [math] Calculating gain matrix in KalmanFilter

I can't comment on the details here but explicitly inverting a matrix is almost always wrong. Sent from my iPhone On Aug 3, 2014, at 8:53, Arne Schwarz schwarz.a...@gmail.com wrote: Hi, I saw that to calculate the gain matrix the accual inverse of the residual covariance matrix is

Re: [math] Calculating bivariate integral

Have you tried nesting univariate integrators? That is the function passed to the first integrator would be something that calls the second integrator? This strategy is disastrous for high dimensionality, but should be adequate with two variable. On Tue, Jul 29, 2014 at 9:11 PM, Marcelo Alves

Re: Parsing and solving algebraic equation from string

On Sun, Jul 20, 2014 at 9:18 PM, Mansour Al Akeel mansour.alak...@gmail.com wrote: As Luc said, it will big project to write a parser that takes any equation as a string, and generate the matrix (2-dimensional array) to feed it into Commons Math. It actually isn't a big project. See

Re: Parsing and solving algebraic equation from string

On Sun, Jul 20, 2014 at 12:01 AM, Luc Maisonobe l...@spaceroots.org wrote: There are no parser in Apache Commons Math to build such systems directly from string representations. We already discussed about this and decided not to implement parsers, as they are already big projects by

Re: Could we have a roots() method in PolynomilFunction class?

That is one article, but it doesn't actually compare the numerical stability or efficiency of this method. It just invokes the stability of numerical linear algebra. Whether this is a good way to compute roots is an open question. The other major question here is operation count. Computing

Re: [math] Min Cost Flow Linear Programming Problem Using Optimization Package

With no inequality constraints, the flow continuity constraint should not require a simplex solver. If there are limitations on maximum flow on some or all links then simplex does come into play. Without such limits, not. IF there are non-linear flow relations such as come into play in

Re: [math] Min Cost Flow Linear Programming Problem Using Optimization Package

In electrical and fluid flow problems, it is customary to encode flow to a node as positive and flow from as negative. This reduces your constraints to a much simpler form Sum_j A_ij = 0 A_ij = A_ji Sent from my iPhone - To

Re: [math] Min Cost Flow Linear Programming Problem Using Optimization Package

=A_ji) for the constraint. However, I didn't (and still don't) see a way to create a constraint in the optimization class that will let me use anything other than a number for the right hand side. Do you know if this library has this ability? On May 22, 2014 8:33 AM, Ted Dunning ted.dunn

Re: Math Fraction, reducing gcd() calls

On Tue, Apr 8, 2014 at 2:52 PM, paul womack pwom...@papermule.co.uk wrote: Gilles wrote: I think that calling gcd ensures that the result will not overflow for the largest possible range of arguments. It's part of the code logic. Maybe you could write methods that implement the naive

Re: [math] Penman–Monteith equation

Why is this more than arithmetic? http://en.wikipedia.org/wiki/Penman%E2%80%93Monteith_equation On Mon, Mar 24, 2014 at 10:22 AM, AJ Weber awe...@comcast.net wrote: Sorry for the newbie question, but has anyone written a java method to solve the Peman-Monteith eq given the daily mean temp,

Re: [math] Penman–Monteith equation

on this java-math-related mailing list has this handy, and is willing to share, whether they leveraged the Commons Math library or not. -AJ On 3/24/2014 1:25 PM, Ted Dunning wrote: Why is this more than arithmetic? http://en.wikipedia.org/wiki/Penman%E2%80%93Monteith_equation On Mon, Mar

Re: [math] solving bivariate quadratic equations

I think that this can actually be solved using linear methods (for the quadratic error). The values of x, x^2, xy, y, y^2 and 1 can be considered coefficients of the terms a, b, c, d, e and f. Linear least squares systems of this form can be solved directly without use of an optimizer by using

Re: [math] solving bivariate quadratic equations

Andrea, How would you like to handle the fact that you may have an infinite number of solutions? Will you be happy with any of them? Or do you somehow want to find all of them? On Thu, Dec 5, 2013 at 5:31 AM, andrea antonello andrea.antone...@gmail.com wrote: Hi, I need a hint about how

[MATH] Re: Sparse matrices not supported anymore?

Commons math decided not to support sparse matrices due to the difficulty of getting them just right. The problem is that 0 * Inf = NaN, not 0. This means that for floating point math, 0 * x = x is not a true identity. The problem really arises when the 0 in question could be either stored as a

Re: [MATH] Re: Sparse matrices not supported anymore?

On Sun, Oct 13, 2013 at 5:17 AM, Gilles gil...@harfang.homelinux.orgwrote: Most sparse matrices just punt and say they are sorry in a very non-IEEE-754 sort of way. How do they do that, practically? Sorry, I was being cute. What I mean is that they libraries implement a sparse matrix

Re: [math] Translate the documentation

My feeling is that documentation donations are always welcome. It is important to mark translations with a version since they will fall out of date. On Tue, Aug 6, 2013 at 3:27 PM, Игорь Цюцюрупа igor.tsutsurup...@gmail.comwrote: Hello, I'm wondering if whether it is necessary to translate

Re: [math] Rotation around given direction

On Mon, Jul 8, 2013 at 9:34 AM, Alexander Nozik alta...@gmail.com wrote: By the way is it normal that I have not received your answer via e-mail? Do I have to be subscribed to receive answers? It is luck of the draw, but mostly you won't get responses without subscribing. Some people may

Re: [math] Mean, Median but no Mode?

Why do you say this is a simple operation? Sent from my iPhone On Jul 4, 2013, at 7:42, Ben Titmarsh ben.titma...@hotmail.co.uk wrote: Hi, I am looking for a library that can provide the mode (http://en.wikipedia.org/wiki/Mode_%28statistics%29) of a set numbers. This is a simple

Re: Matrix exponential?

I think I am under informed here. Isn't the matrix exponential normally computed using eigen decomposition? It seems from the series expansion that all that is involved is to exponentiate the diagonal in the eigen vector form. Sent from my iPhone On May 28, 2013, at 11:18, Michael

Re: Matrix exponential?

of a matrix, the Schur decomposition and eigendecompositions among them. The algorithm implemented by Matlab's expm() uses a Pade approximation and a square-and-rescale technique that is supposedly faster and numerically very robust. On May 28, 2013, at 3:28 PM, Ted Dunning ted.dunn

Re: [math] Gaussian fitter problem

Your question lacks enough details to be certain about what you are doing but if you are fitting a Gaussian distribution defined by exp(-(x-m)^2/(2 s^2))/z then the result can't be negative no matter what. It is possible that your calculation of the gaussian is buggy. Or it is possible that

Re: [math] linear regression output in human readable format.

My recommendation is to write it. This is a pretty simple thing to implement except for a few presentation level details like the naming of the independent variables. If you write it well with test cases, then it will fit your needs and is likely to be adopted and maintained by the Apache

Re: [commons math] - complex matrix inversion

If you really must do this, use a solver and feed it the identity matrix. That is, given the matrix A, solve the matrix system AX = I Any solver that handles complex matrix right hand sides will do this for you. Iterative calls to a solver with successive columns of I can also be used to fill

Re: [commons math] - complex matrix inversion

Modulo certain typos. On Fri, Mar 16, 2012 at 10:52 AM, Luc Maisonobe luc.maison...@free.frwrote: In this case, you can create a FiledMatrixComplex using MatrixUtils.createFildMatrix factory method (or just use a constructor of the field matrix class you prefer). Then use

Re: [math] Re: binomial random generator

On Sat, Oct 22, 2011 at 8:40 PM, Ahmed Abdeen Hamed ahmed.elma...@gmail.com wrote: ... Thanks very much for your quick response. I am doing some simulations that produce probailities which are in turn must be compared to certains rates. Here is an example of what I am doing: if

Re: [math] Distance to Line and Line Segments

You could just define a 3D line that is in a plane. The distance will be the same. On Tue, Aug 2, 2011 at 9:47 AM, Curtis Jensen cur...@the-jensens.orgwrote: I see the 3D Line class has a distance to a point method. Is there something equivalent for the 2D Line class and the 2D Segment

Re: [math] Anyone using BetaDistribution and BetaDistributionImpl

The beta distribution can help with your problem of marking a system as working or not, but I think that a better approach is the Poisson distribution which is intended to describe events occurring in time. The rub is that almost all processes worth monitoring have highly variable rates and all

Re: [math] Anyone using BetaDistribution and BetaDistributionImpl

on what you want to make inference about. Cheers, Mikkel. 2011/3/17 Ted Dunning ted.dunn...@gmail.com: The beta distribution can help with your problem of marking a system as working or not, but I think that a better approach is the Poisson distribution which is intended to describe events

Re: running average of a rate

For the overall average you need is the total time and total characters. Do the division at presentation time. If you want a decaying moving average, then a variant on Welford's method is useful for an on-line estimate. I just had such a discussion in the hbase group. For that you need state,

Re: [math] Re: running average of a rate

On Mon, Mar 14, 2011 at 12:34 PM, Luc Maisonobe luc.maison...@free.frwrote: Le 14/03/2011 15:33, Benson Margulies a écrit : Please excuse the following ignorant question. I want to maintain summary statistics of a rate. At each 'event', I know the number of characters and the time it

Re: [math] Re: running average of a rate

Phil, A big part of the problem as I understand it is that these rates are needed across a potentially quite large distributed system. On Mon, Mar 14, 2011 at 1:42 PM, Phil Steitz phil.ste...@gmail.com wrote: On 3/14/11 12:34 PM, Luc Maisonobe wrote: Le 14/03/2011 15:33, Benson Margulies a

Re: [math] Re: running average of a rate

This approach is fine for relatively well-behaved distributions. Anything more skewed than, say, an exponential or as long tailed as a t(3) distribution is likely to have troubles with this approach. See

Re: [Math] Levenberg Marquardt Help

Do you actually need an optimizer for this? What happened to computing the mean and standard deviation and using those? On Sun, Jan 30, 2011 at 5:08 PM, Ole Ersoy ole.er...@gmail.com wrote: Hi, I'm trying to fit a normal distribution to a curve (I'm assuming the LM Optimizer is a good tool

Re: [Math] Levenberg Marquardt Help

approach to using the LM Optimizer, otherwise it's going to be a long night :). On 01/30/2011 07:30 PM, Ted Dunning wrote: Do you actually need an optimizer for this? What happened to computing the mean and standard deviation and using those? On Sun, Jan 30, 2011 at 5:08 PM, Ole Ersoyole.er

Re: [MATH] Looking for example code for the math.random and math.optimization libraries

While we are at this sort of talk, R has awesome capabilities in this regard as well. On Wed, Dec 8, 2010 at 11:35 AM, Haswell, Joe josiah.d.hasw...@hp.comwrote: If you're starting from scratch, I strongly recommend SciPy/NumPy. The libraries are truly first-rate, Python is absurdly easy to

Re: [Math] Exponential curve fitting problem

Using a single error measure for a wide range of functions doesn't work well (as you have noted). The fundamental problem is that squared error is a *really* bad metric on curves like this. If you plot your original function and the fitted version, you will see what the issue is. I took, for

Re: [math] ComplexFormat parse for inverted complex number

Two variants on this, what about splitting into chunks of the form [\-+]?\d+i? instead? Each chunk could be parsed separately and combined by adding. Secondly, whether or not the inverted form or redundant forms like 0+4i or 5+3+2i are common, is there really any penalty to making the parse be

Re: [math] autocorr

Commons math has a strict backwards compatibility constraint. Apache Mahout does not. For fixed lag, it should only require a few lines of code in Mahout and you should be up and running in a week or so on the trunk version. On Mon, Sep 27, 2010 at 7:47 AM, video axescon vi...@axescon.com

Re: [math] autocorr

and matrix code in it to start with. Commons math seemed to be more logical choice to me. cheers On Mon, Sep 27, 2010 at 11:04 AM, Ted Dunning ted.dunn...@gmail.com wrote: Commons math has a strict backwards compatibility constraint. Apache Mahout does not. For fixed lag, it should only

Re: [math] autocorr

:29 PM, Ted Dunning ted.dunn...@gmail.com wrote: In general, commons math *is* the better choice for general mathematical computing. Their mission is to provide a general mathematical substrate. Apache Mahout's mission is to provide scalable data mining. Part of that requires basic math

Re: [math] autocorr

that it's outside Mahout's domain? On Mon, Sep 27, 2010 at 1:39 PM, Ted Dunning ted.dunn...@gmail.com wrote: Mahout's primary math support is inherited from Colt, but we are actively deleting capabilities from Colt that we don't think will contribute to scalable data mining goal because

Re: [math] autocorr

Everything in Colt was untested and as a result there were bugs and inconsistencies. As part of the Mahout project, we have redefined the matrix primitives to be more amenable to our needs and simpler to extend than the original Colt arrays. We have been busily either testing and converting code

Re: Static versus Transient Logger Declarations

Take Math.sin as an example. Should you have to instantiate a Math object just to compute the sine? On Fri, Sep 10, 2010 at 8:18 PM, Guy Rouillier guyr-...@burntmail.comwrote: On 9/10/2010 9:15 AM, Martin Gainty wrote: Ray and crew other than accomodating a main driver such as public

Re: [MATH] Sparse Matrix - visiting all entries

Apache Mahout also has a matrix package with sparse matrix support. In particular, iterateNonZero is supported and there are multiple sparse vector/matrix formats that provide different performance trade-offs. Our purpose is not necessarily to be a general purpose math package and the system is

Re: [math] Accuracy in root finding with newBrentSolver

R is a statistical package that has nice data analysis capabilities as well as providing a decent matrix arithmetic substrate. It won't help you at all with your computation because it just uses hardware floats. On Mon, Aug 16, 2010 at 4:29 PM, Juan Barandiaran barandiaran.j...@gmail.com wrote:

Re: [math] Accuracy in root finding with newBrentSolver

I think that you need to consider what your problem really is. Is this equation even as accurate as 10^-300? What will the physical consequences of such small errors be? If you really think you need to solve this numerically, then I see that you have two choices: a) use some unbounded

Re: Connection Pooling in Azure Cloud

Distributed applications need a good coordination layer. Apache Zookeeper provides a very nice implementation for this. On Mon, Jul 19, 2010 at 8:15 AM, Praveen Sripati praveensrip...@gmail.comwrote: Servers gets added and removed all the time in the cloud. I am not sure if a change in DBCP

Re: [Math] estimating bucket size for distribution graphs

I would think that the difference between the 75-th %-ile and the 25-th %-ile would be more to the point. On Thu, Jun 10, 2010 at 5:44 AM, Adam Hardy ahardy.str...@cyberspaceroad.com wrote: If I want to distribute my data into buckets for a distribution bar chart or graph, is there a way to

Re: [Math] compare/complement r

Do you mean you are writing C++ to be called from Java? If so, one of Commons Math, Mahout http://lucene.apache.org/mahout/ (with matrix operations derived distantly from Colt) or JMThttp://code.google.com/p/matrix-toolkits-java/ are likely to fit your needs much better. None of these systems

Re: [Math] compare/complement r

Rserve may be of more use to you: http://www.rforge.net/Rserve/ http://www.rforge.net/Rserve/ On Wed, Apr 28, 2010 at 4:45 AM, Sachin Dole sachin.d...@gmail.com wrote: R probably has a large superset of features that math provides while it tries to solve a very different type of problem too.

Re: Why not BigDecimal?

Turner a.g.d.tur...@leeds.ac.ukwrote: Interesting that this is a precision issue. I'm not surprised depending on what you are doing, double precision may not be enough. It depends a lot on how the calculations are broken into smaller parts. BigDecimal is fantastically useful... -- Ted Dunning

Re: Why not BigDecimal?

had used BigDecimal the ranks would have matched to the ones from R. Is there something I am missing? -- Ted Dunning, CTO DeepDyve

Re: [math] Re: [LINEAR] Performance and bugs of 2.0 library

would also be appreciated. Thanks for this work. Up to now we had almost no reliable comparison tools. This will help us improve our library. -- Ted Dunning, CTO DeepDyve

Re: [math] Re: [LINEAR] Performance and bugs of 2.0 library

nearly identical performance. -- Ted Dunning, CTO DeepDyve

Re: new feature: coalesce operator / method

- To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org -- Ted Dunning, CTO DeepDyve

Re: math KMeansPlusPlusClusterer Failing unittest

); assertEquals(1, clusters.size()); } -- Ted Dunning, CTO DeepDyve

Re: JAMA defunct and replaced by Apache Commons-Math?

domain so you can fork it to your heart's content). Commons math is an ongoing, vital project that you can influence and contribute to. On Mon, Oct 19, 2009 at 3:24 AM, Phil Steitz phil.ste...@gmail.com wrote: Commons-math is not a complete replacement for JAMA. -- Ted Dunning, CTO DeepDyve

Re: curve fitting ax^b

= parameters[0]; exp = parameters[1]; power = Math.pow( x, exp ); return ( coef * power ); } // value } // class PowerFunction -- Ted Dunning, CTO DeepDyve

Re: [VFS] Minimum Java version

...@commons.apache.org - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org -- Ted Dunning, CTO DeepDyve

Re: [math] Re: 2D Gaussian Fit

For additional commands, e-mail: user-h...@commons.apache.org - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org -- Ted Dunning, CTO DeepDyve

Re: New Tag - Looking for Comments (Maintain user code during regeneration of files)

to maintain the existing developers code. -- Ted Dunning, CTO DeepDyve

Re: New Tag - Looking for Comments (Maintain user code during regeneration of files)

needs in code generators like jelly. This is a key point and I think we dramatically differ on this. You say that round-tripping is not necessarily a bad thing and I say that it is *necessarily* a bad thing. As in, it is not a good thing. Indeed, it is a bad thing. -- Ted Dunning, CTO DeepDyve

Re: utils to display currency for any bigdecimal

with commons utils which takes care of this internally ? Ted Dunning wrote: I find manuals very handy for questions like this: http://java.sun.com/j2se/1.5.0/docs/api/java/io/PrintWriter.html#printf(java.lang.String,%20java.lang.Objecthttp://java.sun.com/j2se/1.5.0/docs/api/java/io

Re: Basic Maths Help

Ahh... excellent. Chris Bishop's book Pattern Recognition and Machine Learning is a *really* excellent resource for relatively modern machine learning. Also good is Andrew Gelman's book Data Analysis Using Regression and Multilevel Hierarchical Models, but you will have to read between the lines

Re: Convert List to Map

= ListUtils.toMap(list, new SomeTransformerInterface() { void insertIntoMap(Object object, Map map) { SpecificObject s = (SpecificObject) object; map.put(s.getId(), s.getDescription()); } }); Is there a way to do that with commons collection ? Thank you very much -- Ted Dunning, CTO

Re: [collections] LRUMap Problem ConcurrentModificationException

I apologize for not reading your thread with great care, but I think that your problem is pretty clear. The issue is not to do with gets and puts overlapping. The issue is that a put or remove happened during the life of your iterator. One way to avoid this is to synchronize the entire method

Re: proposal: numerical models [physics?]

and the community are very good about helping people start with rough submissions and get them polished enough to fit in well. -- Ted Dunning, CTO DeepDyve

Re: [math] matrix identity, matrix as transformation

interesting. On Mon, Mar 2, 2009 at 6:25 AM, Jelle Herold je...@defekt.nl wrote: I cannot easily extend RealMatrix with these methods by subclassing (because the inherited multiply then wouldn't get me a transform. -- Ted Dunning, CTO DeepDyve

Re: [Math] looking for a dispersion function

29, 2009 at 6:25 PM, Ted Dunning ted.dunn...@gmail.com wrote: Multiply by a reasonably large prime number p and reduce modulo 2^n where n is big enough. Since p and 2^n are relatively prime, this method will permute the numbers in [0, 2^n). You can compute compute q such that p q = 1

Re: [Math] looking for a dispersion function

in the database, or it's amount of data It's easy to convert some long to a String using a 26 based number conversion. I now need some mathematical function to disperse my sequenc-generated ID into the numbers space. Any suggestion ? Nicolas -- Ted Dunning, CTO DeepDyve 4600 Bohannon

Re: Mod_cache for static content

You might consider a dedicated cache like varnish or squid. They make it very easy to factor out this kind of configuration. Sent from my iPhone On Dec 5, 2008, at 16:46, mummana [EMAIL PROTECTED] wrote: I want to use the mod_cache ONLY for the static files. When I use the below

Re: Evaluating performance of DBUtils

will be substantial and you will not have the impact of changing frameworks. Really. On Tue, Nov 25, 2008 at 11:43 AM, vupt vupt [EMAIL PROTECTED] wrote: I am restricted from using any frameworks like Hibernate, Spring, Ibatis. -- Ted Dunning, CTO DeepDyve 4600 Bohannon Drive, Suite 220 Menlo Park, CA 94025

Re: [math] Fwd: [jira] Commented: (MAHOUT-65) Add Element Labels to Vectors and Matrices

) in string format. The idea is to keep things simple by avoiding optional parts. Luc - Mail Original - De: Ted Dunning [EMAIL PROTECTED] À: Commons Users List user@commons.apache.org Envoyé: Mardi 21 Octobre 2008 12:31:54 GMT +01:00 Amsterdam / Berlin / Berne / Rome / Stockholm / Vienne

Re: [math] Utility method to aggregate Statistics

Or maybe it would be interesting to request it as an Improvement to the Commons Math developers, adding an aggregator to all Statistics implementations? If you want to request this improvement, please open a ticket for it using our JIRA tracking system:

Re: isEscaped

On Wed, Sep 3, 2008 at 11:33 AM, Garrett Smith [EMAIL PROTECTED]wrote: This example: assertTrue( StringEscapeUtils.isHtmlEscaped(lt;bgt;textlt;/bgt;) ); - is flawed. The flaw is searching for unescaped entities, not searching for no unescaped entities. ... You make some good

Re: isEscaped

Isn't this a pretty simple regex? Just look for 's and 's without entity syntax. On Tue, Sep 2, 2008 at 11:28 AM, Gabriel Reis [EMAIL PROTECTED] wrote: Hi, Is there any tool to verify if a String is escaped? Something like this: assertFalse( StringEscapeUtils.isHtmlEscaped(btext/b) );

Re: isEscaped

suspect that creating a really robust test would involve dealing with a number of gotchas. For example, is this string escaped? StringEscapeUtils.isHtmlEscaped (Use this HTML: 'lt;bgt;textlt;/bgt;') -- fas F. Andy Seidl MyST Technology Partners, Inc. -Original Message- From: Ted

Re: Question about TestUtils.chiSquare

I doubt that you really want a chi^2 test for this in any case. You could use it if you binned the amounts so that you are comparing counts, but you would only find out if there was a difference, not whether there was an interesting difference. Most likely, what you want is an unpaired,

[math] Why do continuous distributions not have a density method

I note that the continuous distributions in the commons math package don't have an entry point to compute the probability density function. Clearly some distributions have some points where the PDF is undefined, but why is there no method for all of the distributions where it is defined? Is this