D.2.2.18 primecoeffs

Procedure from library general.lib (see general_lib).

Usage:

primecoeffs(J[,q]); J any type which can be converted to a matrix e.g. ideal, matrix, vector, module, int, intvec
q = intger

Compute:

primefactors <= min(p,32003) of coeffs of J (default p = 32003)

Return:

a list, say l, of two intvectors:
l[1] : the different primefactors of all coefficients of J l[2] : the different remaining factors

Note:

the procedure works for small integers only, just by testing all primes (not to be considerd as serious prime factorization!)

Example:

LIB "general.lib";
primecoeffs(intvec(7*8*121,7*8));"";
→ [1]:
→    2,7,11
→ [2]:
→    1
→ 
ring r = 0,(b,c,t),dp;
ideal I = -13b6c3t+4b5c4t,-10b4c2t-5b4ct2;
primecoeffs(I);
→ [1]:
→    2,5,13
→ [2]:
→    _[1]=1