Hi, I have written a numerical optimizer for LTSpice IV. It automatically adjusts component values to meet circuit performance targets you set. For example maximum power output and minimum supply current.
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At the moment there is a free trial version available. Depending on sales and the general level of interest I may write a new 4.2 version and make the old version available for free for non-commercial use. Anyway I invite you to give it a try and send your comments and queries to the e-mail address on the site.