https://bugs.kde.org/show_bug.cgi?id=362507
Bug ID: 362507
Summary: Factorial(13) does not
Product: kalgebra
Version: 0.11
Platform: Mint (Ubuntu based)
URL: http://abload.de/img/factorial_13_is_wrong7isuq.png
OS: Linux
Status: UNCONFIRMED
Severity: grave
Priority: NOR
Component: general
Assignee: aleix...@kde.org
Reporter: gerdr...@gmail.com
This has cost me almost an hour of my precious study time.
The factorial function will give wrong results from exactly 13 on.
I.e.
factorial (12) = 12*11*10*9*8*7*6*5*4*3*2*1 = 479001600
That is just fine.
But from 13 on, the result seems to pass a limit or whatver and gives back a
wrong result...
13*12*11*10*9*8*7*6*5*4*3*2*1
=6227020800
(the same what Wolfram Alpha would return for 13! )
but, using the factorial function
factorial(13)
=1932053504
Which is wrong.
Factorial(14) will be wrong as well...
Reproducible: Always
Steps to Reproduce:
1. Start kAlgebra
2. In the Input box type "12*11*10*9*8*7*6*5*4*3*2*1", hit Enter
3. in the input box type "ans*13", hit enter
4. Now input "factorial(12)" in the input box, hit enter
5. Now input "factorial(13)" in the input box, hit enter
6. Compare results.
Actual Results:
Factorial function is not the same as equivalent when value is 12!.
Expected Results:
13! or "factorial(13)" gives the correct value
Severity: a calculator that does surprisingly give back wrong results when you
dont expect it is worthless.
I had to debug a long equation step by step to find out the part with
factorial(13) will give the wrong result.
Here the kAlgebra script
-------------------- save as factorial.kal and load in kAlgebra for convenience
--------------
1
factorial(1)
2*1
factorial(2)
3*2*1
factorial(3)
4*3*2*1
factorial(4)
5*4*3*2*1
factorial(5)
6*5*4*3*2*1
factorial(6)
7*6*5*4*3*2*1
factorial(7)
8*7*6*5*4*3*2*1
factorial(8)
9*8*7*6*5*4*3*2*1
factorial(9)
10*9*8*7*6*5*4*3*2*1
factorial(10)
11*10*9*8*7*6*5*4*3*2*1
factorial(11)
12*11*10*9*8*7*6*5*4*3*2*1
factorial(12)
13*12*11*10*9*8*7*6*5*4*3*2*1
factorial(13)
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