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/* Copyright 2000 by Jeffrey Chang. All rights reserved.
* This code is part of the Biopython distribution and governed by its
* license. Please see the LICENSE file that should have been included
* as part of this package.
*
* cmathfnsmodule.c
* Created 3 Jun 2000
*/
#include "Python.h"
#include <math.h>
#include "csupport.h"
/************************************** Exported Functions ***********/
static char cmathfns_intd__doc__[] =
"intd(x[, digits_after_decimal]) -> int x, rounded\n\
\n\
Represent a floating point number with some digits after the\n\
decimal point as an integer. This is useful when floating point\n\
comparisons are failing due to precision problems. e.g.\n\
intd(5.35, 1) -> 54.\n\
\n\
";
static PyObject *cmathfns_intd(
PyObject *self, PyObject *args, PyObject *keywds)
{
PyObject *digits_after_decimal = Py_None;
double x, digits;
double precision;
static char *kwlist[] = {"x", "digits_after_decimal", NULL};
if(!PyArg_ParseTupleAndKeywords(args, keywds, "d|O", kwlist,
&x, &digits_after_decimal))
return NULL;
if(digits_after_decimal == Py_None)
digits = 0;
else {
digits = PyNumber_AsDouble(digits_after_decimal);
if(PyErr_Occurred()) {
return NULL;
}
}
precision = pow(10, digits);
if(x >= 0)
x = (int)(x * precision + 0.5);
else
x = (int)(x * precision - 0.5);
return PyFloat_FromDouble(x);
}
static char cmathfns_fcmp__doc__[] =
"fcmp(x, y, precision) -> -1, 0, or 1";
static PyObject *cmathfns_fcmp(
PyObject *self, PyObject *args, PyObject *keywds)
{
double x, y, precision;
int result;
static char *kwlist[] = {"x", "y", "precision", NULL};
if(!PyArg_ParseTupleAndKeywords(args, keywds, "ddd", kwlist,
&x, &y, &precision))
return NULL;
if(fabs(x-y) < precision)
result = 0;
else if(x < y)
result = -1;
else result = 1;
return PyInt_FromLong(result);
}
static char cmathfns_safe_log__doc__[] =
"safe_log(n, zero=None, neg=None) -> log(n)\n\
\n\
Calculate the log of n. If n is 0, returns the value of zero. If n is\n\
negative, returns the value of neg.\n\
\n\
";
static PyObject *cmathfns_safe_log(
PyObject *self, PyObject *args, PyObject *keywds)
{
PyObject *zero = Py_None,
*neg = Py_None;
double n;
static char *kwlist[] = {"n", "zero", "neg", NULL};
if(!PyArg_ParseTupleAndKeywords(args, keywds, "d|OO", kwlist,
&n, &zero, &neg))
return NULL;
if(n < 0) {
Py_INCREF(neg);
return neg;
} else if(n < 1E-100) {
Py_INCREF(zero);
return zero;
}
return PyFloat_FromDouble(log(n));
}
/************************************** Module definition stuff ******/
static PyMethodDef cmathfnsMethods[] = {
{"fcmp", (PyCFunction)cmathfns_fcmp, METH_VARARGS|METH_KEYWORDS,
cmathfns_fcmp__doc__},
{"intd", (PyCFunction)cmathfns_intd, METH_VARARGS|METH_KEYWORDS,
cmathfns_intd__doc__},
{"safe_log", (PyCFunction)cmathfns_safe_log, METH_VARARGS|METH_KEYWORDS,
cmathfns_safe_log__doc__},
{NULL, NULL}
};
static char cmathfns__doc__[] =
"This provides helper functions for the mathfns module.\n\
You should never import this module on its own.\n\
\n\
";
void initcmathfns(void)
{
(void) Py_InitModule3("cmathfns", cmathfnsMethods, cmathfns__doc__);
}
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