Coverage for local/lib/python2.7/site-packages/sage/libs/gmp/randomize.pxd : 53%

""" 

Generate random rationals in Sage 

""" 

from sage.libs.gmp.mpz cimport * 

from sage.libs.gmp.mpq cimport * 

from sage.misc.randstate cimport randstate, current_randstate, SAGE_RAND_MAX 

########################### 

cdef inline void mpq_randomize_entry(mpq_t x, mpz_t num_bound, mpz_t den_bound): 

cdef randstate rstate = current_randstate() 

mpz_urandomm(mpq_numref(x), rstate.gmp_state, num_bound) 

mpz_urandomm(mpq_denref(x), rstate.gmp_state, den_bound) 

if mpz_sgn(mpq_denref(x)) == 0: 

mpz_set_si(mpq_denref(x),1) 

if rstate.c_random() % 2: 

mpz_mul_si(mpq_numref(x), mpq_numref(x), -1) 

mpq_canonicalize(x) 

cdef inline void mpq_randomize_entry_nonzero(mpq_t x, mpz_t num_bound, mpz_t den_bound): 

mpq_randomize_entry(x, num_bound, den_bound) 

while mpq_sgn(x) == 0: 

mpq_randomize_entry(x, num_bound, den_bound) 

cdef inline void mpq_randomize_entry_as_int(mpq_t x, mpz_t bound): 

cdef randstate rstate = current_randstate() 

mpz_urandomm(mpq_numref(x), rstate.gmp_state, bound) 

mpz_set_si(mpq_denref(x), 1) 

if rstate.c_random() % 2: 

mpz_mul_si(mpq_numref(x), mpq_numref(x), -1) 

cdef inline void mpq_randomize_entry_as_int_nonzero(mpq_t x, mpz_t bound): 

mpq_randomize_entry_as_int(x, bound) 

while mpq_sgn(x) == 0: 

mpq_randomize_entry_as_int(x, bound) 

cdef inline void mpq_randomize_entry_recip_uniform(mpq_t x): 

cdef randstate rstate = current_randstate() 

# Numerator is selected the same way as ZZ.random_element(); 

# denominator is selected in a similar way, but 

# modified to give only positive integers. (The corresponding 

# probability distribution is $X = \mbox{trunc}(1/R)$, where R 

# varies uniformly between 0 and 1.) 

cdef int den = rstate.c_random() - SAGE_RAND_MAX/2 

if den == 0: den = 1 

mpz_set_si(mpq_numref(x), (SAGE_RAND_MAX/5*2) / den) 

den = rstate.c_random() 

if den == 0: den = 1 

mpz_set_si(mpq_denref(x), SAGE_RAND_MAX / den) 

mpq_canonicalize(x) 

cdef inline void mpq_randomize_entry_recip_uniform_nonzero(mpq_t x): 

mpq_randomize_entry_recip_uniform_nonzero(x) 

while mpq_sgn(x) == 0: 

mpq_randomize_entry_recip_uniform_nonzero(x)