Roots of a function: Difference between revisions
m
add ooRexx
(Added default C++ translation to C#.) |
Walterpachl (talk | contribs) m (add ooRexx) |
||
Line 2,008:
x = x + step;
endwhile</lang>
=={{header|ooRexx}}==
<lang oorexx>/* REXX program to solve a cubic polynom equation
a*x**3+b*x**2+c*x+d =(x-x1)*(x-x2)*(x-x3)
*/
Numeric Digits 16
pi3=Rxcalcpi()/3
Parse Value '1 -3 2 0' with a b c d
p=3*a*c-b**2
q=2*b**3-9*a*b*c+27*a**2*d
det=q**2+4*p**3
say 'p='p
say 'q='q
Say 'det='det
If det<0 Then Do
phi=Rxcalcarccos(-q/(2*rxCalcsqrt(-p**3)),16,'R')
Say 'phi='phi
phi3=phi/3
y1=rxCalcsqrt(-p)*2*Rxcalccos(phi3,16,'R')
y2=rxCalcsqrt(-p)*2*Rxcalccos(phi3+2*pi3,16,'R')
y3=rxCalcsqrt(-p)*2*Rxcalccos(phi3+4*pi3,16,'R')
End
Else Do
t=q**2+4*p**3
tu=-4*q+4*rxCalcsqrt(t)
tv=-4*q-4*rxCalcsqrt(t)
u=qroot(tu)/2
v=qroot(tv)/2
y1=u+v
y2=-(u+v)/2 (u+v)/2*rxCalcsqrt(3)
y3=-(u+v)/2 (-(u+v)/2*rxCalcsqrt(3))
End
say 'y1='y1
say 'y2='y2
say 'y3='y3
x1=y2x(y1)
x2=y2x(y2)
x3=y2x(y3)
Say 'x1='x1
Say 'x2='x2
Say 'x3='x3
Exit
qroot: Procedure
Parse Arg a
return sign(a)*rxcalcpower(abs(a),1/3,16)
y2x: Procedure Expose a b
Parse Arg real imag
xr=(real-b)/(3*a)
If imag<>'' Then Do
xi=(imag-b)/(3*a)
Return xr xi'i'
End
Else
Return xr
::requires 'rxmath' LIBRARY</lang>
{{out}}
<pre>p=-3
q=0
det=-108
phi=1.570796326794897
y1=2.999999999999999
y2=-3.000000000000000
y3=0.000000000000002440395154978758
x1=2
x2=0
x3=1.000000000000001</pre>
=={{header|PARI/GP}}==
| |||