Sciwise, In your request for me to calculate an image you didn't specify: - initial x & y values (for p1), or - a bailout value (p2) so I'm arbitrarily using these values: params=0.73899999999999999/0.73899999999999999/64/0 taken from the parm file found in the original FreeBASIC.net formula source post... I turned *periodicity testing off* and used passes=1 for image accuracy. Your corner location X, Y specifications match the X and Y values calculated by Richard's Fractint 4 Win beta 5 from the center-mag values in your parm file -- *after* using the manually applied correction of: x-mag=0.75 *required* to compensate for a bug in Fractint for Windows beta 5. Below is the final par file & formula I used to calculate your requested image -- using the additional info given above: And the .GIF image it creates: http://www.emarketingiseasy.com/TESTS/Fractals/VltLtRq0.gif Anti-aliased version: http://www.emarketingiseasy.com/TESTS/Fractals/VltLtRq1.jpg Is that what you were expecting to see, sciwise? <--<< ---------------------------------------------------------- VHeunS02 { ; Calc Request & parms fm sciwise. Nov 20, 2015 ; ; sciwise's Volterra Lotka formula (with modified ; initialization; and bailout repair used.) ; ; p, h are variable. ; ; frm - sciwise modified ver of 1993 V-Heun formula: "V-HeunPH", ; repaired, parameterized. ; reset=2004 type=formula formulafile=fractint.frm formulaname=V-HeunPH center-mag=0.998748/0.0716808/1.338358 float=y maxiter=2048 params=0.73899999999999999/0.73899999999999999/64/0 inside=bof61 outside=0 logmap=yes colors=@blues.map } frm:V-HeunPH { ; Sciwise's FRM REPAIRED BY RESTORING BAILOUT TEST -HHL x=real(p1) y=imag(p1) p=real(pixel) h=imag(pixel): u=x-x*y w=-y+x*y a=x+p*u b=y+p*w c=x+h*(u+(a-a*b)) d=y+h*(w+(-b+a*b)) x=c y=d z=x+flip(y) |z|<=p2 } ---------- End of par file ---------------------- - Hal Lane ######################## # hallane@earthlink.net ######################## -----Original Message----- From: Fractint [mailto:fractint-bounces@mailman.xmission.com] On Behalf Of sciwise@ihug.co.nz Sent: Friday, November 20, 2015 8:40 PM To: Fractint and General Fractals Discussion <fractint@mailman.xmission.com> Subject: [Fractint] V-HeunPH a limited region The images that you are generating from my simple formula. in the p , h plane are fascinating ; perhaps you can do a similar treatment using these parameters. top left X 0.0025031289111390 y 0.8188647746243739 bottom right x 1.9949937421777222 y -0.6755031853255635 ----- vhpp.par ------------- test { reset=2004 type=formula formulafile=fractint.frm formulaname=V-HeunPH center-mag=0.998748/0.0716808/1.338358 float=y maxiter=2048 inside=bof61 outside=0 logmap=yes colors=@blues.map } --------- end par ------- I wasn't expecting the p , h plane ,to be overly complicated , however you can never tell when fractals are involved. The next step is to take the V-HeunPH values and use them with V-Heun. Using the vhpp.par file we obtaim a type of curve that's at the boundary between the unstable outside and the ultra stable inside ; values from this region are what I may initially use for V-Huen , however your explorations are suggesting other possibilities. _______________________________________________ Fractint mailing list Fractint@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/fractint --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus