Dear Marco,
Solution one
http://www.holoborodko.com/pavel/mpfr/
Second solution
see attachment
Vincent
Le 05/02/2017 à 02:20, mmarco a écrit :
I am working in a C++ library that provides some certified homotopy
continuations. It provides a function that, takes as input a list of
floating point numbres and returns another such list.
I am having a lot of trouble trying to write a sage-cython interface for
mpfr floats (the version for doubles works ok).
I have tried to use vectors, lists and malloc'ed arrays, but none of them
seems to work. mpfr_t' are so tricky.
Whis is the right way to write such a cython interface?
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at https://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
from libc.stdlib cimport malloc, free
from sage.libs.mpfr cimport *
from sage.rings.real_mpfr cimport RealNumber, RealField_class, RealField
cdef class RealVector(object):
cdef RealField_class _real_field
cdef size_t _length
cdef mpfr_ptr _data
def __cinit__(self, data, length, prec):
cdef int i
self._data = <mpfr_ptr> malloc(length * sizeof(__mpfr_struct))
self._length = length
for i in range(self._length):
mpfr_init2(self._data + i, prec)
def __dealloc__(self):
cdef int i
for i in range(self._length):
mpfr_clear(self._data + i)
free(self._data)
def __init__(self, data, length, prec):
self._real_field = RealField(prec)
cdef int i
if data:
for i in range(self._length):
self[i] = data[i]
def __repr__(self):
cdef int i
return "[" + ", ".join(self[i].str() for i in range(self._length)) + "]"
def __len__(self):
return self._length
def __setitem__(self, Py_ssize_t i, RealNumber x):
if not 0 <= i < self._length:
raise IndexError
mpfr_set(self._data + i, x.value, self._real_field.rnd)
def __getitem__(self, Py_ssize_t i):
if not 0 <= i < self._length:
raise IndexError
cdef RealNumber x = self._real_field._new()
mpfr_set(x.value, self._data + i, self._real_field.rnd)
return x
