void import

Fraktalism/README.md

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+# Fraktalism
+
+## Iterative computing inside !
+
+Voyons d'abord
+[une vidéo](http://la.buvette.org/fractales/f90/video.html)
+qui montre ma première expérience dans ce domaine.
+
+## La technique
+
+Le gros des calculs de fractales est fait dans XXX, et la gestion
+des pixels 'physiques' est fait dans YYY
+
+Des scripts _shell_ sont utilisés pour construire les vidéos.
+
+## TODO
+
+- Voir de près le calcul du cadrage 
+- Rajouter des formules
+- Ne pas procastiner
+

Fraktalism/mkmandel.f90

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+!-----------------------------------------------------
+!		IMAGE PROCESSING
+!-----------------------------------------------------
+!-----------------------------------------------------
+
+subroutine plotsomething(pic, start, cz)
+    use cmplxmath
+    use imagetools
+
+    implicit none
+
+    integer, intent(inout), dimension (:,:)  ::  pic
+    complex, intent(in)                      ::  start
+    type (CenterMag), intent(in)             :: cz
+
+    integer   :: ix, iy, width, height
+    real      :: fx, fy, mod2
+    complex   :: za, zb, cste
+    integer   :: iter, maxiter
+    logical   :: escape
+
+    print *, "> plotsomething"
+
+    width  = ubound(pic, 1)
+    height = ubound(pic, 2)
+    print *, "  pic size ", width, height
+    print *, "  start ", start
+    call print_centermag(cz)
+
+    !   initialise constants
+    ! 
+    maxiter =  999;
+
+    !   enter megaloop
+    ! 
+    do iy = 1, height
+        fy = (float(iy) / float(height/3)) - 1.5
+        !! print *, "line  ", iy, fy
+        do ix = 1, width
+            fx = (float(ix) / float(width/3)) - 2.0
+
+            !! print *, "pixel ", ix, iy, " at ", fx, fy
+            !-------------------------------------
+            !     working on the current pixel
+            za   = start
+            cste = complex ( fx, fy )
+            iter = 0
+            escape = .FALSE.
+            do while (iter .lt. maxiter)
+                zb = (za * za) + cste
+                ! if (modulus2(zb) .gt. 4.0) then
+                mod2 =  real(zb)*real(zb) + aimag(zb)*aimag(zb)
+                !! print *, "mod2  ", mod2
+                if (mod2 .GT. 4.0) then
+                    escape = .TRUE.
+                    exit
+                endif
+                za = zb
+                iter = iter + 1
+                !! print *, "ZA ITER ESCAPE", za, iter, escape
+            enddo
+
+            if (escape) then
+                pic(ix, iy) = mod(iter, 333)
+            else
+                ! esoteric computation here
+                ! pic(ix, iy) = mod(8*floor(mod2*11.11), 24)
+                pic(ix, iy) = mod(iter, 222)
+            endif
+            !-------------------------------------
+        end do           ! fin boucle sur X
+
+    end do
+
+end
+
+!-----------------------------------------------------
+! 
+!    this is the main programm
+! 
+program image
+
+    use imagetools
+
+    implicit none
+
+    interface
+      subroutine plotsomething (pic, start, cz)
+          use imagetools
+          integer,   intent(inout), dimension (:,:) ::  pic
+          complex,   intent(in)                     ::  start
+          type (CenterMag), intent(in)              :: cz
+      end subroutine plotsomething
+    end interface
+
+    integer, dimension(768, 768)    ::    picz
+    type (CenterMag)                ::    cm
+    integer                         ::    angle
+    real                            ::    radangle, radius
+    real                            ::    stx, sty
+    character (len=80)              ::    filename
+
+    cm%cx    = 0.0 ; cm%cy    = 0.0 ;  cm%mag   = 3.0
+    picz = 0                ! clear screen
+
+    print *, "-------- making some mandelbrot -------"
+
+    do angle = 0, 1800
+
+        radangle = float(angle) * 0.017453292522222
+        radius   = float(angle) / 2000.0
+        write (filename, "(a, i5.5, a)") "img/", angle, ".pnm"
+        ! filename = trim(filename)
+        print *, "#### passe ", angle, radangle, trim(filename)
+
+        stx = radius * sin(radangle*4.0)
+        sty = radius * cos(radangle*3.0)
+
+        call plotsomething (picz, complex(stx, sty), cm)
+        call spitaspnm (picz, trim(filename))
+
+        print *
+
+    enddo
+
+    print *, "[DONE]"
+
+end
+
+!-----------------------------------------------------