Feigenbaum constant calculation: Difference between revisions

=={{header|RPL}}==

{{trans|Python}}

{{works with|Halcyon Calc|4.2.7}}

{| class="wikitable"

! RPL code

! Python code

|-

|

≪ { }

13 10 → maxit maxitj

≪ 3.2 1 0

2 maxit 1 + '''FOR''' ii

DUP2 - 4 PICK / 3 PICK +

1 maxitj 1 + '''START'''

0 0

1 2 ii ^ '''START'''

OVER * 2 * 1 SWAP -

3 PICK ROT SQ - SWAP '''NEXT'''

/ - '''NEXT'''

3 PICK ROT - OVER 4 PICK - /

5 ROLL OVER + 5 ROLLD

4 ROLL DROP SWAP ROT '''NEXT'''

3 DROPN

≫ ≫

´'''FBAUM'''’ STO

|

'''FBAUM''' ''( -- { δ1..δ13 } )''

max_it, max_it_j = 13, 10

d1, a1, a2 = 3.2, 1, 0

for i in range(2, max_it + 1):

a = a1 + (a1 - a2) / d1

for j in range(1, max_it_j + 1):

x = y = 0

for k in range(1, (1 << i) + 1):

y = 1.0 - 2.0 * y * x

x = a - x * x

a = a - x / y

d = (a1 - a2) / (a - a1)

print(d)

d1, a2, a1 = d, a1, a

clean stack

.

.

|}

{{out}}

<pre>

1: { 3.21851142204 4.38567759857 4.60094927654 4.65513049539 4.66611194782 4.66854858152 4.66906066029 4.66917155686 4.6691951528 4.66920033694 4.66920090912 4.66920429563 4.66917851362 }

</pre>

The above program (limited at 10 iterations) takes 33 minutes and 50 seconds to be executed on a HP-28S.