Look! Wiggly-squiggly chromatic strands. Another example of the vesatility of the
fractint formula parser. If you want to give the floating point unit of your processor
a rest go to http://maxitersfractalfollies.blogspot.com for the ready made gif
and a bonus jpg.
fract378.gif { ; threadedness
; blank
; calctime 0:03:07.35
; created Aug 24, 2010
; Fractint Version 2004 Patchlevel 9
reset=2004 type=formula formulafile=kerrym.frm
formulaname=astrd-nr_jul_rjr3 center-mag=0.935569/-0.147609/2.480433
params=-0.891170995208594/0.3318887905514695/1/3/-0.0674153874324778/-0.\
3227942747276223/90/25 float=y maxiter=1500 inside=0 outside=atan
decomp=256 periodicity=0
colors=000302403503504604705805806907A07B08B08C09D1AE1AF1BF1BG1CH1CI1DI1\
EJ1EK1FL1FL1GM1GN1HO2IN2KM2NK2QJ2TH2VG2YE2`D2cB1fA1i81l71n51q41t21w00z03\
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IM2HK2GJ2FH2DG2CE2BD2AB19A18817715514413212000000101201
}
frm:astrd-nr_jul_rjr3 { ; Kerry Mitchell 14nov98
;
; Kerry Mitchell's explanation of his "Astroid" formulas is
; at the end of formula "Astroid"
;
; colors Julia set by orbit's closet approach to
; a astroid: x^n + y^n = a^n
;
; p1 = c = Julia parameter
; real(p2) = a = size
; imag(p2) = n = exponent
; p3 = center of astroid
; bailout = 1000 (hardcoded)
; rotation angle, degrees = 0 (hardcoded)
;
; colors inside & outside points the same way
; use decomp=256, float=yes, periodicity=no
;
zc=pixel, c=p1, iter=1, done=0
bailout=1000, errmin=bailout
a=real(p2), n=imag(p2), aton=a^n
center=p3, rot=p4/180*pi, rot=exp(flip(rot))
:
;
; standard iteration
;
iter=iter+1, zc=sqr(zc)+c
;
; compute difference between actual location and
; astroid location; update minimum if necessary
;
temp=(zc-center)*rot
x=cabs(real(temp)), y=cabs(imag(temp))
err=cabs(x^n+y^n-aton)
IF (err<errmin)
errmin=err
ENDIF
;
; bailout at escape or maximum iterations
; set "done" flag
; use log(minimum) as angle for decomp coloring
;
IF ((|zc|>bailout)||(iter==maxit))
done=1
t=log(errmin)
z=cos(t)+flip(sin(t))
ENDIF
done==0
;SOURCE: 98msg.frm
}
Roger Alexander