tag:blogger.com,1999:blog-5952320191615496730.comments2017-06-28T16:32:59.962+01:00The Beginner ProgrammerMicnoreply@blogger.comBlogger94125tag:blogger.com,1999:blog-5952320191615496730.post-29737975693674276042017-06-28T16:32:59.962+01:002017-06-28T16:32:59.962+01:00Hi,
First of all thanks for this post. Very infor...Hi,<br /><br />First of all thanks for this post. Very informative.<br />I am struggling to install "mxnet" package in my R. <br /><br />Could you please guide what needs to be done in order to use it. <br />RISHABH DIMRIhttp://www.blogger.com/profile/15170512421288647760noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-70496103164053213832017-06-27T09:10:03.154+01:002017-06-27T09:10:03.154+01:00Hey, I am getting error in Q learning formula.The ...Hey, I am getting error in Q learning formula.The error is " too many indices for array".How to solve that?Vishwas Paihttp://www.blogger.com/profile/10159247864555712567noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-86416211812351988682017-06-19T22:44:14.210+01:002017-06-19T22:44:14.210+01:00Hi, the idea was to have a look at the signal in t...Hi, the idea was to have a look at the signal in the frequency domain using the fast fourier transform. As far as I know, a FIR system/filter is a different thing.Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-79204131770362441782017-06-17T19:31:21.135+01:002017-06-17T19:31:21.135+01:00Isn't this is what is called FIR filter? Only,...Isn't this is what is called FIR filter? Only, you avoid the FFT -- > IFFT, just do convolution.Debrajhttp://www.blogger.com/profile/07329208979141534447noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-28991786119171337912017-05-23T18:42:44.855+01:002017-05-23T18:42:44.855+01:00Hi, so for my final table all my predicted labels ...Hi, so for my final table all my predicted labels are marked as 1, why is that? i guess that is what preventing from the final result be similar to yoursOmer Manhttp://www.blogger.com/profile/06408219117728181210noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-88045476667689526242017-05-21T20:59:34.150+01:002017-05-21T20:59:34.150+01:00Hi Ola, it seems that the problem is that in your ...Hi Ola, it seems that the problem is that in your example you're passing to the copula::mvdc function an object that is not of class "parCopula". The "mardia" argument is not a copula from the copula package but (probably) a numeric vector. More generally, since the "mardia" object seems to have been generated using the function copBasic::asCOP, I think that the packages copBasic and copula may not be compatible with each other. This means that if you build the Mardia copula with the copBasic package functions, it probably won't be accepted as an argument in most of the functions in the copula (and probably vinecopula too) package.<br /><br />My suggestion is to clearly define what your goal and steps are, then look for a suitable R package and stick to it. If you have specific questions on your project, you can try to ask on CrossValidated (https://stats.stackexchange.com/). People there are usually very competent in their subjects and nice, although I must say there's not that much on copulas there either.<br /><br />As a last suggestion, if you are doing this for work or study, I suggest you to get in contact with some good university professor/PhD that might be willing to help with the project (Masters student in stats might be interested in writing a thesis on an R implementation of the mardia copula and related functions/tests/applications). <br /><br />I wish you all the best.<br />MicMichttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-45084741174197382842017-05-19T22:26:08.067+01:002017-05-19T22:26:08.067+01:00Hi Mic, thank you for your quick response. That...Hi Mic, thank you for your quick response. That's great that I have possibility to speak with you! Yes, you're right, I read documentation for "copula" and "VineCopula" many times and there is no mention about Mardia. I've tried to put formula for Mardia copula and then built bivariate distirbution with specified marginals in the fallowing way:<br />> df<-read.table("R_popr.txt", header = TRUE)<br />> xy<-df[,c("x","y")]<br />> m<-pobs(xy$x)<br />> mm<-pobs(xy$y)<br />fun<-function(u,v) 0.1*u*v+0.4*max(0,u+v-1)+0.5*min(u,v)<br />mardia<-asCOP(m,mm,fun)<br />mycdf<-mvdc(mardia, margins = c("exp","exp"), paramMargins = list(list(rate=2),list(rate=2))))<br /><br />but I got error:<br />Error in validObject(.Object) : <br /> invalid class “mvdc” object: invalid object for slot "copula" in class "mvdc": got class "numeric", should be or extend class "parCopula"<br />As we see, the two datasets have a similar structure. This is evidence that the proposed model is appropriate.<br /><br /><br />Could you please advise on above?<br /><br />Also, I tried to compare empirical copula with the theoretical one, but I encouner the problem. It is easy to use cdfcomp when argument ft is a list of "fitdist" objects - so for example in case of fitting copula without specified marginals, but it is no possible to compare distributions of object mvdc using cdfcomp. Do you know how the comparison of pdf's can be done for mvdc object? The same problem is with gofCopula.<br /><br />Sorry that I have so many questions to you :)<br /><br />Thank you,<br />OlaAleksandra Piórkowskahttp://www.blogger.com/profile/08619733351123134181noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-20548293067869236732017-05-15T15:46:36.106+01:002017-05-15T15:46:36.106+01:00Hi Ola! Glad to know you found it useful! As far a...Hi Ola! Glad to know you found it useful! As far as I know the best copula packages in R should be "copula" and "VineCopula". Both packages feature Archimedean copulas. In the documentation, however, there seems to be no mention about Mardia's. Maybe you can ask the developers if they plan to add that particular copula.Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-8716602237236726562017-05-14T21:52:22.450+01:002017-05-14T21:52:22.450+01:00Hi Mic! It was really useful for me. Thanks for th...Hi Mic! It was really useful for me. Thanks for that! <br />I've started working with R 2 weeks ago and I am consider if there is Mardia copula also in some package?<br /><br />Thanks!<br />OlaAleksandra Piórkowskahttp://www.blogger.com/profile/08619733351123134181noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-66445125022033774132017-05-04T16:54:52.369+01:002017-05-04T16:54:52.369+01:00I've always been taught that inter-arrival tim...I've always been taught that inter-arrival times (think of people in a shop or even failures in mechanical components) can, and sometimes are modeled through the use of the exponential distribution. This was a simple attempt at doing that. By taking a look at the histograms of the data, I assumed the distribution was close enough to an exponential and went on from there. I didn't run any goodness of fit test but simply fit the distribution, simulate some data and compared them with the original. <br /><br />If you were to use such model in a real-life context for taking decisions, a more in-depth analysis may be a better option. For instance, your test showed that a Weibull distribution might be a better fit given the data at hand. Using the Weibull (which by the way I think is used in reliability engineering too!) would probably lead to simulated data closer to the real one.Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-71326051686174458702017-05-04T04:47:28.837+01:002017-05-04T04:47:28.837+01:00why do you think the results differ, your analysis...why do you think the results differ, your analysis suggests it to be exponential distribution...Amolhttp://www.blogger.com/profile/06091657848165747896noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-74643245451589170922017-05-03T20:54:12.435+01:002017-05-03T20:54:12.435+01:00Hi Amol, thanks for sharing the results!Hi Amol, thanks for sharing the results!Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-31882867144974146812017-05-03T17:47:22.699+01:002017-05-03T17:47:22.699+01:00I ran the data provided by you to identify the typ...I ran the data provided by you to identify the type of data it exactly is in minitab and it shows it to be 3-Parameter Weibull.<br /><br />Goodness of Fit Test<br /><br />Distribution AD P LRT P<br />Normal 3.101 <0.005<br />Lognormal 0.455 0.262<br />3-Parameter Lognormal 0.215 * 0.128<br />Exponential 1.923 0.011<br />2-Parameter Exponential 1.416 0.032 0.012<br />Weibull 0.339 >0.250<br />3-Parameter Weibull 0.272 >0.500 0.132<br />Smallest Extreme Value 7.958 <0.010<br />Largest Extreme Value 0.644 0.091<br />Gamma 0.196 >0.250<br />3-Parameter Gamma 0.185 * 0.360<br />Logistic 1.531 <0.005<br />Loglogistic 0.383 >0.250<br />3-Parameter Loglogistic 0.319 * 0.578Amolhttp://www.blogger.com/profile/06091657848165747896noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-72006116755644690532017-04-21T12:59:25.363+01:002017-04-21T12:59:25.363+01:00Hi Maarten! Thanks!Indeed they are quite challengi...Hi Maarten! Thanks!Indeed they are quite challenging! I'm a bit rusty when it comes to VaR, however, I believe that having the pdf, the cdf and being able to simulate observations should be enough to start. Having said this, you need to make some assumption about the distribution of the returns/indeces/phoenomena that you are trying to model, choose the copula, fit it, then get the multivariate distribution that in my code I called "my_dist". Once you're there, you can get the density using dMvdc, the cdf using pMvdc and simulate observations using rmvdc (for instance for a Monte Carlo VaR). Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-21159344105357914532017-04-20T18:25:27.549+01:002017-04-20T18:25:27.549+01:00Hi Mic! Nice post! I still have a question though....Hi Mic! Nice post! I still have a question though..I'm also currently working on a project where I have to calculate VaR of different market indices for different periods after fitting several copulas. However, copulas have proven to be quite a challenge for an average master student. My code returns the same VaR for all the periods..so clearly I'm missing/overlooking something..can you tell me where (in your explanation) I should apply VaR? <br />Thanks!Maarten Vanzieleghemhttp://www.blogger.com/profile/08221048349567688861noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-16012507201130034222017-04-13T06:41:43.888+01:002017-04-13T06:41:43.888+01:00I really appreciate information shared above. It’s...I really appreciate information shared above. It’s of great help. If someone want to learn Online (Virtual) instructor lead live training in R Tool, kindly contact us http://www.maxmunus.com/contact<br />MaxMunus Offer World Class Virtual Instructor led training on R Tool. We have industry expert trainer. We provide Training Material and Software Support. MaxMunus has successfully conducted 100000+ trainings in India, USA, UK, Australlia, Switzerland, Qatar, Saudi Arabia, Bangladesh, Bahrain and UAE etc.<br />For Demo Contact us:<br />Name : Arunkumar U <br />Email : arun@maxmunus.com<br />Skype id: training_maxmunus<br />Contact No.-+91-9738507310<br />Company Website –http://www.maxmunus.com<br /><br /><br />Arun Kumarhttp://www.blogger.com/profile/12925256203702412312noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-52629399853845937652017-04-06T17:42:06.847+01:002017-04-06T17:42:06.847+01:00This comment has been removed by the author.Unknownhttp://www.blogger.com/profile/12556978141696702330noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-50954612217968604902017-04-06T13:08:53.772+01:002017-04-06T13:08:53.772+01:00Thanks. It's a nice post about probability de...Thanks. It's a nice post about <a href="http://www.actucation.com/calculus-2/advanced-definite-integration/probability-distribution/probability-on-random-distribution" rel="nofollow">probability density function</a>. I really like it :). It's really helpful. Good job.Deepak Suwalkahttp://www.blogger.com/profile/16838354928057786238noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-29668047402590381222017-03-15T22:20:55.387+00:002017-03-15T22:20:55.387+00:00That was very flattering! :) Thank you!That was very flattering! :) Thank you!Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-17498003971666469132017-03-15T14:22:44.227+00:002017-03-15T14:22:44.227+00:00It shouldn't said this is for beginners only, ...It shouldn't said this is for beginners only, I have master in math and this was better than the books I'm reading right now (I'm not gonna say what r they :))AKhttp://www.blogger.com/profile/07199292786030119935noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-72268358089841764892017-03-07T18:49:34.271+00:002017-03-07T18:49:34.271+00:00Hi Lenchik! Thanks for reading the post! I didn...Hi Lenchik! Thanks for reading the post! I didn't know it was already available in R, thanks for letting me know. Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-63965524106145320182017-03-07T13:07:15.243+00:002017-03-07T13:07:15.243+00:00Hi, thanks for post. Hope you make more posts on n...Hi, thanks for post. Hope you make more posts on neural networks using R.<br />Why not use Olivetti faces from RnavGraphImageData package and stay fully in R?Lenchikhttp://www.blogger.com/profile/11800097563024079205noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-27739285777333746122017-03-05T09:48:41.604+00:002017-03-05T09:48:41.604+00:00Hi Arno, thanks for reading the post and for your ...Hi Arno, thanks for reading the post and for your comment.<br /><br />In general, the model will be able to discriminate only if you've told it how to do that. For instance if you have two faces in the same picture, in the example above it will "chose" to output as an answer either one or the other face, since it has not been trained to do otherwise.<br /><br />If you have more labels in the same picture, you can either try to separate them and then pass each one to a classifier, use a different model, or even use some more sophisticated tools such as openCV with Python which can detect objects in a picture very accurately. Ultimately the choice will depend on the details of the specific problem you are trying to solve.Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-66380207528551210122017-03-04T07:24:15.714+00:002017-03-04T07:24:15.714+00:00Hi, thanks for the detailed post.
The dataset inp...Hi, thanks for the detailed post. <br />The dataset inputted in the model is 40 faces, with 10 variations each. I am trying, however, to apply the algorithm on biological populations of cells.<br />Supposing we have a good training dataset of biological cells of various population (let says, 10 cell-line, with 100 pictures for each population). Does the algorithm described above could perform a discrimination of 2 or more population when cells mixed in an image? I am not sure if the presented algorithms would allows to do so. Thank you for your reply,<br /><br />ArnoUnknownhttp://www.blogger.com/profile/08122094411116133119noreply@blogger.comtag:blogger.com,1999:blog-5952320191615496730.post-36113949260210715432017-02-25T20:13:39.978+00:002017-02-25T20:13:39.978+00:00Thank you for reading!Thank you for reading!Michttp://www.blogger.com/profile/18151225177833588981noreply@blogger.com