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Hi Tyn- > Further to my previous message, I already found some answers to some of my > questions. However, can you comment on the ??? below. > > > What are the numerical equivalents for the other propagations methods to > > set int errorMode correctly? > > Data.NO_ERROR = 202 > Data.INDEPENDENT = ??? > Data.DEPENDENT = ??? Data.INDEPENDENT = 200 Data.DEPENDENT = 201 I've added the following to GridUtil so you can use them there: public static final int NO_ERRORS = Data.NO_ERRORS; public static final int DEPENDENT_ERRORS = Data.DEPENDENT; public static final int INDEPENDENT_ERRORS = Data.INDEPENDENT; I've also added an error mode to the sampleToReal. sample already had the error mode signature. These will be in tomorrow's build. > http://www.unidata.ucar.edu/software/idv/docs/javadoc/constant-values.html#ucar.unidata.data.grid.GridUtil.DEFAULT_ERROR_MODE > > > Is there a javadoc showing all propagations methods? > > NO, except this snippet in > http://www.unidata.ucar.edu/mailing_lists/archives/visad/2002/msg00170.html: > > > > Also, I can see that Data.INDEPENDENT uses a linear 'error > > propagation' algorithm, but what does actually Data.DEPENDENT do (doesn't > > one need to know the functional form of the dependency?). Is there any > > auxiliary documentation somewhere, or references to the algorithms used? > > For Data.DEPENDENT the system uses the worst case error > propagation, where they are simply added. This is essentially > interval arithmetic. For Data.INDEPENDENT the system uses > root mean square error propagation. I don't know any more than what was in that message. As Bill pointed out, this has not been tested very well. I have no experience using the error propagation, but if you run into problems, we can muddle along together. ;-) Don > -----Original Message----- > From: Unidata IDV Support [mailto:address@hidden] > Sent: Wednesday, May 13, 2009 12:25 AM > To: Valentijn Venus > Cc: address@hidden > Subject: [IDV #MQM-696970]: visad error propagation facility > > Hi Tyn- > > > thanks! > > > > Unfortunately, not everything is done with visad. > > It will be difficult to do the error propagation fully then. > > > On the IDV side, would it take a lot of work to for all methods to pass an > > error propagation type other than Data.NO_ERROR? Do you think Willem could > > handle such a task? > > You'd need a way for the user to set the error mode and then modify all the > methods in GridUtil that take a sampling method to also take an error mode. > I took a stab at the latter, but not sure I got all the methods yet. Then > any of the controls/methods that do sampling would need to implement this > as well. > > I'm sure there are other gotcha's out there. We're in the middle of > finalizing the 2.7 release, so don't have time to work on this. If > Willem wants to look into it I can try to answer some of his questions. > > Don > > > Ticket Details > =================== > Ticket ID: MQM-696970 > Department: Support IDV > Priority: Normal > Status: Open > > > Internal Virus Database is out of date. > Checked by AVG - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.9.17/1845 - Release Date: 12/12/2008 > 9:02 AM > Faculty of Geo-Information Science and Earth Observation (ITC) > University of Twente > > E-mail disclaimer > The information in this e-mail, including any attachments, is intended for > the addressee only. If you are not the intended recipient, you are hereby > notified that any disclosure, copying, distribution or action in relation to > the content of this information is strictly prohibited. If you have received > this e-mail by mistake, please delete the message and any attachment and > inform the sender by return e-mail. ITC accepts no liability for any error or > omission in the message content or for damage of any kind that may arise as a > result of e-mail transmission. > > Ticket Details =================== Ticket ID: MQM-696970 Department: Support IDV Priority: Normal Status: Open