Polynomial long division: Difference between revisions
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end program PolyDivTest</lang>
=={{Header|FreeBASIC}}==
<lang FreeBASIC>#define EPS 1.0e-20
type polyterm
degree as uinteger
coeff as double
end type
sub poly_print( P() as double )
dim as string outstr = "", sri
for i as integer = ubound(P) to 0 step -1
if outstr<>"" then
if P(i)>0 then outstr = outstr + " + "
if P(i)<0 then outstr = outstr + " - "
end if
if P(i)=0 then continue for
if abs(P(i))<>1 then
if outstr="" then
outstr = outstr + str((P(i)))
else
outstr = outstr + str(abs(P(i)))
end if
end if
if i>0 then outstr=outstr+"x"
sri= str(i)
if i>1 then outstr=outstr + "^" + sri
next i
print outstr
end sub
function lc_deg( B() as double ) as polyterm
'gets the coefficent and degree of the leading term in a polynomial
dim as polyterm ret
for i as uinteger = ubound(B) to 0 step -1
if B(i)<>0 then
ret.degree = i
ret.coeff = B(i)
return ret
end if
next i
return ret
end function
sub poly_multiply( byval k as polyterm, P() as double )
'in-place multiplication of polynomial by a polynomial term
dim i as integer
for i = ubound(P) to k.degree step -1
P(i) = k.coeff*P(i-k.degree)
next i
for i = k.degree-1 to 0 step -1
P(i)=0
next i
end sub
sub poly_subtract( P() as double, Q() as double )
'in place subtraction of one polynomial from another
dim as uinteger deg = ubound(P)
for i as uinteger = 0 to deg
P(i) -= Q(i)
if abs(P(i))<EPS then P(i)=0 'stupid floating point subtraction, grumble grumble
next i
end sub
sub poly_add( P() as double, byval t as polyterm )
'in-place addition of a polynomial term to a polynomial
P(t.degree) += t.coeff
end sub
sub poly_copy( source() as double, target() as double )
for i as uinteger = 0 to ubound(source)
target(i) = source(i)
next i
end sub
sub polydiv( A() as double, B() as double, Q() as double, R() as double )
dim as polyterm s
dim as double sB(0 to ubound(B))
poly_copy A(), R()
dim as uinteger d = ubound(B), degr = lc_deg(R()).degree
dim as double c = lc_deg(B()).coeff
while degr >= d
s.coeff = lc_deg(R()).coeff/c
s.degree = degr - d
poly_add Q(), s
poly_copy B(), sB()
redim preserve sB(0 to s.degree+ubound(sB)) as double
poly_multiply s, sB()
poly_subtract R(), sB()
degr = lc_deg(R()).degree
redim sB(0 to ubound(B))
wend
end sub
dim as double N(0 to 4) = {-42, 0, -12, 1} 'x^3 - 12x^2 - 42
dim as double D(0 to 2) = {-3, 1} ' x - 3
dim as double Q(0 to ubound(N)), R(0 to ubound(N))
polydiv( N(), D(), Q(), R() )
poly_print Q() 'quotient
poly_print R() 'remainder</lang>
{{out}}
<pre>x^2 - 9x - 27
-123</pre>
=={{header|GAP}}==
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