Function=[sin|cos|sinh|cosh|exp|log|sqr|...]) is specified with this type. Prior to version 14, these types were mandelsine, mandelcos, mandelsinh, mandelcos, and mandelexp. Same comment about our lapses into the old terminology as above!
These are "pseudo-Mandelbrot" mappings for the LambdaFn Julia functions. They map to their corresponding Julia sets via the spacebar command in exactly the same fashion as the original M/J sets. In general, they are interesting mainly because of that property (the function=exp set in particular is rather boring). Generate the appropriate "Mandelfn" set, zoom on a likely spot where the colors are changing rapidly, and hit the spacebar key to plot the Julia set for that particular point.
Try "FRACTINT TYPE=MANDELFN CORNERS=4.68/4.76/-.03/.03 FUNCTION=COS" for a graphic demonstration that we're not taking Mandelbrot's name in vain here. We didn't even know these little buggers were here until Mark Peterson found this a few hours before the version incorporating Mandelfns was released.
Note: If you created images using the lambda or mandel "fn" types prior to version 14, and you wish to update the fractal information in the "*.fra" file, simply read the files and save again. You can do this in batch mode via a command line such as:
"fractint oldfile.fra savename=newfile.gif batch=yes"
For example, this procedure can convert a version 13 "type=lambdasine" image to a version 14 "type=lambdafn function=sin" GIF89a image. We do not promise to keep this "backward compatibility" past version 14 - if you want to keep the fractal information in your *.fra files accurate, we recommend conversion. See GIF Save File Format .