From snoke at vt.edu Fri Jul 9 13:01:13 2010 From: snoke at vt.edu (Arthur Snoke) Date: Fri, 9 Jul 2010 16:01:13 -0400 (EDT) Subject: [SAC-HELP] a problem while downsampling sac data with decimate In-Reply-To: References: <20100525155015.200935rzftl73qtz@webmail.ogs.trieste.it> Message-ID: This thread was in late May. Partly as a result of it, I looked more closely at the INTERPOLATE command. For version 101.4, we replaced the truncate with a round off when calculating NPTS, but since then I found other things that should probably be changed. If one uses the current version carefully, it should work satisfactorily, so a patch is not required. However, I thought I should post to this list to see if anyone has any problems with my proposed changes. I am attaching a PDF version of the revised HELP file. In the current version, there is a default DELTA of 0.025 s. Hence, if one enters INTERPOLATE NPTS 4096, the end time will change to a value that depends on how the input DELTA compares to 0.025. I think that the start and end times should not change with INTERPOLATE, and do not understand the need/use of a default DELTA. in the revised version, if NPTS is called for as an argument, DELTA is calculated -- just as if DELTA is input, NPTS is calculated. I do not understand when one would use BEGIN. It seems to me more logical to use CUT before calling INTERPOLATE. I have left it in, so it can be used with either NPTS or DELTA. In the current HELP file, there are logical arguments for NPTS and BEGIN that are not needed to be mentioned explicitly. Another calling argument is EPSILON. It is incorrectly described in both the current HELP file and the source code. It is effectively a "water level" that gives a lower limit to the ratios that are used in the Wiggins procedure. I have used this procedure for many years, both in my own programs and in those written by others. I have never seen a reason to vary EPSILON and tests show that for a reasonable time series there is no effect on changing EPSILON by factors of 100. I have left it in, but not advertised it in the HELP file. One final comment about this interpolation routine: When Wiggins wrote t in 1976, it was intended to be used for hand-digitized data. Typically, one included extrema and (perhaps) inflection points. A difference between this scheme and cubic splines is that the output file will not have greater extrema than the input data points. It is also not as smooth as a cubic spline interpolation because second derivatives are not forced to be continuous. This scheme works well for data if the DELTA is not changed too much. Following up on the original thread, it should probably not be done if one is down-sampling by a large amount both because the fit will probably not be very good and because there is no anti-aliasing filtering done within INTERPOLATE. For such a case, it is best to use DECIMATE. Please comment -- especially if you disagree with anything I have said. Arthur Snoke snoke at vt.edu -------------- next part -------------- A non-text attachment was scrubbed... Name: INTERPOLATE.pdf Type: application/pdf Size: 92436 bytes Desc: URL: From omromero at miners.utep.edu Mon Jul 12 20:18:28 2010 From: omromero at miners.utep.edu (omromero at miners.utep.edu) Date: Mon, 12 Jul 2010 21:18:28 -0600 Subject: [SAC-HELP] installation problem! Message-ID: Hello, I am trying to install the 32 bit sac version in a 32 bit ubuntu 10.04, but working in a 64 bit computer, until this time I am unsuccesful. The reason for doing that is, I have previously intalled PASSCAL and antelope software in this same 32 bit Ubuntu system and they work well; but they did not work using the 64 bit Ubuntu system. (I repeat: I have a laptop 64 bit working with 32 bit Ubuntu 10.04) Now I am stucked with SAC (32 bit) because it does not work in this 32 bit ubuntu. I have tried also, the 64 bit version and neither it does not work. I have set all the environment variables and paths and I run the command sac, I get only the next displayed information: :~$ Total: 30.79 over 3 days. What does this displayed information mean? please, any suggestion is welcome sincerely Oscar Romero Ph. D. student in University of Texas at El Paso -------------- next part -------------- An HTML attachment was scrubbed... URL: From vallee at geoazur.unice.fr Tue Jul 20 08:51:32 2010 From: vallee at geoazur.unice.fr (Martin Vallee) Date: Tue, 20 Jul 2010 17:51:32 +0200 Subject: [SAC-HELP] problem with "mat" command, v101.4 64 bits Message-ID: <4C45C604.8090503@geoazur.unice.fr> Dear users/managers of SAC, I compiled the source of version 101.4 enabling the matlab interface. but after reading a SAC file, and using the command "mat", I have the following error : SAC> r 2003.268.19.54.42.1751.G.ECH.00.BHZ.D.SAC SAC> mat Starting Matlab computational engine... Allocating and filling Matlab workspace arrays... Copying to Matlab workspace ... ERROR: Could not create struct array in matCreateTimesStruct. Do you have an idea about this problem? Thank you very much in advance, Martin Vall?e -- /---------------------------------------------------------/ / Martin Vall?e ! vallee at geoazur.unice.fr / / Charg? de recherche IRD ! tel: (33) 4 92 94 26 47 / / GEOAZUR ! fax: (33) 4 92 94 26 10 / / 250, rue A. Einstein, F-06560 VALBONNE / /---------------------------------------------------------/ From rob at seismo.berkeley.edu Tue Jul 20 09:44:39 2010 From: rob at seismo.berkeley.edu (Rob Porritt) Date: Tue, 20 Jul 2010 09:44:39 -0700 Subject: [SAC-HELP] sac 101.4-mac_osx_64 binaries distributed by IRIS Message-ID: Hi all, I received the binary version of sac this morning as listed in the subject. I use bash as my main shell on my mac and when sourcing the sacinit.sh script I found a syntax error repeated for all similar usages: export SAC_DISPLAY_COPYRIGHT 1 instead of export SAC_DISPLAY_COPYRIGHT=1 Also, a collaborator of mine installed with sacinit.csh using the sac source code and found the sacinit.csh sets: setenv SACHOME /usr/local/jas/sac instead of setenv SACHOME /usr/local/sac Similar problems are in the sacinit.sh with SACHOME and the "=" as above. Rob -- Rob Porritt, GG UC Berkeley Earth and Planetary Sciences PhD Candidate Berkeley Seismological Laboratory http://seismo.berkeley.edu/~rob/ -------------- next part -------------- An HTML attachment was scrubbed... URL: From f.darbyshire at gmail.com Thu Jul 22 07:15:52 2010 From: f.darbyshire at gmail.com (Fiona Darbyshire) Date: Thu, 22 Jul 2010 10:15:52 -0400 Subject: [SAC-HELP] Running an executable (not a shell script) from within SAC - is the $run command obsolete? Message-ID: Dear All, I recently installed SAC101.4 on my system (Linux). Since then, I have been having problems running some of my macros. I tried to find some documentation in the new-look SAC manual and in the CHANGES listings on the website, but didn't see anything pertinent to the problem. Here's the issue: I have a SAC macro from which I call a program (a fortran-based executable) that requires user input. Up to now it's been automated as follows in the macros: ... $run myprogram input1 input2 etc... $endrun Now whenever I try to run any macros that incorporates a "$run... $endrun" command, I get a segmentation fault. Has the procedure for running programs from within SAC changed and, if so, what is the new syntax? Thanks, Fiona Darbyshire Centre de recherche GEOTOP Universit? du Qu?bec ? Montr?al -------------- next part -------------- An HTML attachment was scrubbed... URL: