There is a new development snapshot available ... http://gnucap.org/devel/gnucap-2008-05-27.tar.gz
Models (optional) have also been updated: http://gnucap.org/devel/gnucap-2008-05-27-models-bsim.tar.gz http://gnucap.org/devel/gnucap-2008-05-27-models-jspice3-2.5.tar.gz http://gnucap.org/devel/gnucap-2008-05-27-models-ngspice17.tar.gz http://gnucap.org/devel/gnucap-2008-05-27-models-spice3f5.tar.gz Another optional package contains some tools. There are no changes, but there is a new one for consistency. http://gnucap.org/devel/gnucap-2008-05-27-tools.tar.gz This file contains the md5sum of the other files, so you can check for a proper download: http://gnucap.org/devel/gnucap-2008-05-27.md5sum This snapshot provides: 1. Choice of Gear-2 method for numerical differentiation. 2. Refinements of time step control ... 2a. most components participate. 2b. some new "options" 3. "store" command. stashes data for post-processing 4. New models tarball -- the models from "Jspice", including Josephson Junction. Comments: This is still very much a development snapshot, and should not be included in any distribution or CD. 1. Choice of Gear-2 method .. Specify ".option method=gear". or "gear2" Choices are trap, euler, gear. Step control with Gear method is based on truncation error, but less rigourously than when Trap method is specified. This is because Gear's method induces errors in the third derivative when time step is changed. It is usually not noticeable visually, but very noticeable in the third derivative which is used for step control. As a work-around, step control is based on the second derivative instead. 2. Refinements of time step control By default, time step control should maintain smoothness such that if you fit the data with cubic splines, the interpolated points will be within tolerance. Some new options are added: "trsteporder", default=3, set step size so an interpolating spline of this order will be within tolerance. "trstepcoef1", "trstepcoef2", "trstepcoef3" Coefficients of the error term of the truncated series, 1st, 2nd, 3rd order. Only one applies, the one specified in "trsteporder". There is still more work to be done. 3. "store" command. stashes data for post-processing "store" command .. (should it be "save"? but "save" is a conflict) --- stores data for post-processing. Some post-processing commands "measure" type are coming soon. It is possible to write a plug-in that will use this data, but none are included in this snapshot. Watch [EMAIL PROTECTED] to see some as they come out. 4. New models tarball -- the models from "Jspice", including Josephson Junction. Not all of them work. Some fail to attach, like other model plugins. This is incomplete work. I believe the JJ does work, but without the optional current sense. 5. Performance comments: In a previous announcement, I said "Performance with spice model plugins is very slow" .. It is not as bad as indicated, but nothing has been done about it. When comparing speed between gnucap and spice, using model plugins, the dominant time is usually taken by model evaluation. The same models should run in the same time. In some cases, gnucap's stricter time control can result in slower run time. I have examples where Spice gives completely wrong answers because of step control problems. In these cases, gnucap is slower because it does more time steps, and correct because of it. 6. Plugins using the spice-wrapper still do not take named parameters, or expressions. === As usual, to get started you need only the main package gnucap-2008-xx-xx.tar.gz . The other "models" packages contain the exact models from the various sources. If you need a jfet, I recommend the one in "spice3f5". If you need a BSIM model, the obvious choice is the "bsim" package, which has all of them. The "ngspice17" package contains a few models not available elsewhere, such as "vbic". Making a models package available is not an endorsement of those models. The intent is that by using plugins, models designed for as many other simulators as possible can be used by gnucap. If you need other models, let me know. _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
