[Fractint] Brite Strands

24 Aug 2010


      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\
  z07z0Bz0Fz0Jz0Nz0Rz0Vz0Zz0bz0fz0jz0nz0rz0vz0zz0xz0vz0tz0rz0pz0nz0lz0jz0h\
  z0fz0dz0bz0`z0Zz0Xz0Wz0Uz0Sz0Qz0Oz0Mz0Kz0Iz0Gz0Ez0Cz0Az08z06z04z02z00z00\
  y10x20v20u30s40r50p50o61n71l81k91i91hA1gB1eC1dC1bD1aE1_F1ZF1YG1WH1VI1TJ2\
  SJ2RK2PL2OM2MM2LN2JO2IM2GJ2EH2CE1AC18916614312000101302503605806A07C19D1\
  9E1AF1AF1BG1BH1CI1DI1DJ1EK1EL1FL1FM1GN1HO2IO2JQ2IS2HV2GX2F_2Da2Cd2Bf2Ah1\
  9k18m17p15r14u13w12z00z20z50z70zA0zC0zF0zH0zK0zM0zP0zR0zU0zX0zZ0za0zc0zf\
  0zh0zk0zm0zp0zr0zu0zw0zz0zw0zu0zr0zo0zl0zj0zg0zd0za0z_0zX0zU0zS0zP0zM0zJ\
  0zH0zE0zB0z80z60z30z00x01v02s03q04n06l07i08g19e1Ab1B`1CY1EW1FT1GR1HO2JN2\
  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