示例#1
0
double npy_hypot(double x, double y)
{
    double yx;

    if (npy_isinf(x) || npy_isinf(y)) {
        return NPY_INFINITY;
    }

    if (npy_isnan(x) || npy_isnan(y)) {
        return NPY_NAN;
    }

    x = npy_fabs(x);
    y = npy_fabs(y);
    if (x < y) {
        double temp = x;
        x = y;
        y = temp;
    }
    if (x == 0.) {
        return 0.;
    }
    else {
        yx = y/x;
        return x*npy_sqrt(1.+yx*yx);
    }
}
示例#2
0
npy_cdouble cbesh_wrap2_e( double v, npy_cdouble z) {
  int n = 1;
  int kode = 2;
  int m = 2;
  int nz, ierr;
  int sign = 1;
  npy_cdouble cy;

  cy.real = NPY_NAN;
  cy.imag = NPY_NAN;

  if (npy_isnan(v) || npy_isnan(z.real) || npy_isnan(z.imag)) {
    return cy;
  }
  if (v < 0) {
    v = -v;
    sign = -1;
  }
  F_FUNC(zbesh,ZBESH)(CADDR(z), &v, &kode, &m, &n, CADDR(cy), &nz, &ierr);
  DO_SFERR("hankel2e:", &cy);
  if (sign == -1) {
    cy = rotate(cy, -v);
  }
  return cy;
}
示例#3
0
npy_cdouble cbesk_wrap_e( double v, npy_cdouble z) {
  int n = 1;
  int kode = 2;
  int nz, ierr;
  npy_cdouble cy;

  cy.real = NPY_NAN;
  cy.imag = NPY_NAN;

  if (npy_isnan(v) || npy_isnan(z.real) || npy_isnan(z.imag)) {
    return cy;
  }
  if (v < 0) {
    /* K_v == K_{-v} even for non-integer v */
    v = -v;
  }
  F_FUNC(zbesk,ZBESK)(CADDR(z), &v, &kode, &n, CADDR(cy), &nz, &ierr);
  DO_SFERR("kve:", &cy);
  if (ierr == 2) {
    if (z.real >= 0 && z.imag == 0) {
      /* overflow */
      cy.real = NPY_INFINITY;
      cy.imag = 0;
    }
  }

  return cy;
}
示例#4
0
int pbdv_wrap(double v, double x, double *pdf, double *pdd) {

  double *dv;
  double *dp;
  int num;

  if (npy_isnan(v) || npy_isnan(x)) {
    *pdf = NPY_NAN;
    *pdd = NPY_NAN;
    return 0;
  }
  /* NB. Indexing of DV/DP in specfun.f:PBDV starts from 0, hence +2 */
  num = ABS((int)v) + 2;
  dv = (double *)PyMem_Malloc(sizeof(double)*2*num);
  if (dv==NULL) {
    sf_error("pbdv", SF_ERROR_OTHER, "memory allocation error");
    *pdf = NPY_NAN;
    *pdd = NPY_NAN;
    return -1;
  }
  dp = dv + num;
  F_FUNC(pbdv,PBDV)(&v, &x, dv, dp, pdf, pdd);
  PyMem_Free(dv);
  return 0;
}
示例#5
0
npy_cdouble cbesj_wrap_e( double v, npy_cdouble z) {
  int n = 1;
  int kode = 2;
  int nz, ierr;
  int sign = 1;
  npy_cdouble cy_j, cy_y, cwork;

  cy_j.real = NPY_NAN;
  cy_j.imag = NPY_NAN;
  cy_y.real = NPY_NAN;
  cy_y.imag = NPY_NAN;

  if (npy_isnan(v) || npy_isnan(z.real) || npy_isnan(z.imag)) {
    return cy_j;
  }
  if (v < 0) {
    v = -v;
    sign = -1;
  }
  F_FUNC(zbesj,ZBESJ)(CADDR(z), &v, &kode, &n, CADDR(cy_j), &nz, &ierr);
  DO_SFERR("jve:", &cy_j);
  if (sign == -1) {
    if (!reflect_jy(&cy_j, v)) {
      F_FUNC(zbesy,ZBESY)(CADDR(z), &v,  &kode, &n, CADDR(cy_y), &nz, CADDR(cwork), &ierr);
      DO_SFERR("jve(yve):", &cy_y);
      cy_j = rotate_jy(cy_j, cy_y, v);
    }
  }
  return cy_j;
}
示例#6
0
文件: ndtr.c 项目: 87/scipy
double ndtr(double a)
{
double x, y, z;

if (npy_isnan(a)) {
  mtherr("ndtr", DOMAIN);
  return (NPY_NAN);
}

x = a * SQRTH;
z = fabs(x);

if( z < SQRTH )
	y = 0.5 + 0.5 * erf(x);

else
	{
	y = 0.5 * erfc(z);

	if( x > 0 )
		y = 1.0 - y;
	}

return(y);
}
示例#7
0
npy_cdouble cbesy_wrap( double v, npy_cdouble z) {
  int n = 1;
  int kode = 1;
  int nz, ierr;
  int sign = 1;
  npy_cdouble cy_y, cy_j, cwork;

  cy_j.real = NPY_NAN;
  cy_j.imag = NPY_NAN;
  cy_y.real = NPY_NAN;
  cy_y.imag = NPY_NAN;

  if (npy_isnan(v) || npy_isnan(z.real) || npy_isnan(z.imag)) {
    return cy_y;
  }
  if (v < 0) {
    v = -v;
    sign = -1;
  }

  if (z.real == 0 && z.imag == 0) {
      /* overflow */
      cy_y.real = -NPY_INFINITY;
      cy_y.imag = 0;
      sf_error("yv", SF_ERROR_OVERFLOW, NULL);
  }
  else {
      F_FUNC(zbesy,ZBESY)(CADDR(z), &v,  &kode, &n, CADDR(cy_y), &nz, CADDR(cwork), &ierr);
      DO_SFERR("yv:", &cy_y);
      if (ierr == 2) {
          if (z.real >= 0 && z.imag == 0) {
              /* overflow */
              cy_y.real = -NPY_INFINITY;
              cy_y.imag = 0;
          }
      }
  }

  if (sign == -1) {
    if (!reflect_jy(&cy_y, v)) {
      F_FUNC(zbesj,ZBESJ)(CADDR(z), &v,  &kode, &n, CADDR(cy_j), &nz, &ierr);
      DO_SFERR("yv(jv):", &cy_j);
      cy_y = rotate_jy(cy_y, cy_j, -v);
    }
  }
  return cy_y;
}
示例#8
0
npy_cdouble cbesi_wrap( double v, npy_cdouble z) {
  int n = 1;
  int kode = 1;
  int sign = 1;
  int nz, ierr;
  npy_cdouble cy, cy_k;

  cy.real = NPY_NAN;
  cy.imag = NPY_NAN;
  cy_k.real = NPY_NAN;
  cy_k.imag = NPY_NAN;

  if (npy_isnan(v) || npy_isnan(z.real) || npy_isnan(z.imag)) {
    return cy;
  }
  if (v < 0) {
    v = -v;
    sign = -1;
  }
  F_FUNC(zbesi,ZBESI)(CADDR(z), &v,  &kode, &n, CADDR(cy), &nz, &ierr);
  DO_SFERR("iv:", &cy);
  if (ierr == 2) {
    /* overflow */
    if (z.imag == 0 && (z.real >= 0 || v == floor(v))) {
        if (z.real < 0 && v/2 != floor(v/2))
            cy.real = -NPY_INFINITY;
        else
            cy.real = NPY_INFINITY;
        cy.imag = 0;
    } else {
        cy = cbesi_wrap_e(v*sign, z);
        cy.real *= NPY_INFINITY;
        cy.imag *= NPY_INFINITY;
    }
  }

  if (sign == -1) {
    if (!reflect_i(&cy, v)) {
      F_FUNC(zbesk,ZBESK)(CADDR(z), &v,  &kode, &n, CADDR(cy_k), &nz, &ierr);
      DO_SFERR("iv(kv):", &cy_k);
      cy = rotate_i(cy, cy_k, v);
    }
  }

  return cy;
}
示例#9
0
文件: igami.c 项目: BranYang/scipy
double igami(double a, double p)
{
    int i;
    double x, fac, f_fp, fpp_fp;

    if (npy_isnan(a) || npy_isnan(p)) {
	return NPY_NAN;
    }
    else if ((a < 0) || (p < 0) || (p > 1)) {
	mtherr("gammaincinv", DOMAIN);
    }
    else if (p == 0.0) {
	return 0.0;
    }
    else if (p == 1.0) {
	return NPY_INFINITY;
    }
    else if (p > 0.9) {
	return igamci(a, 1 - p);
    }

    x = find_inverse_gamma(a, p, 1 - p);
    /* Halley's method */
    for (i = 0; i < 3; i++) {
	fac = igam_fac(a, x);
	if (fac == 0.0) {
	    return x;
	}
	f_fp = (igam(a, x) - p) * x / fac;
	/* The ratio of the first and second derivatives simplifies */
	fpp_fp = -1.0 + (a - 1) / x;
	if (npy_isinf(fpp_fp)) {
	    /* Resort to Newton's method in the case of overflow */
	    x = x - f_fp;
	}
	else {
	    x = x - f_fp / (1.0 - 0.5 * f_fp * fpp_fp);
	}
    }

    return x;
}
示例#10
0
npy_cdouble cbesi_wrap_e( double v, npy_cdouble z) {
  int n = 1;
  int kode = 2;
  int sign = 1;
  int nz, ierr;
  npy_cdouble cy, cy_k;

  cy.real = NPY_NAN;
  cy.imag = NPY_NAN;
  cy_k.real = NPY_NAN;
  cy_k.imag = NPY_NAN;

  if (npy_isnan(v) || npy_isnan(z.real) || npy_isnan(z.imag)) {
    return cy;
  }
  if (v < 0) {
    v = -v;
    sign = -1;
  }
  F_FUNC(zbesi,ZBESI)(CADDR(z), &v,  &kode, &n, CADDR(cy), &nz, &ierr);
  DO_SFERR("ive:", &cy);

  if (sign == -1) {
    if (!reflect_i(&cy, v)) {
      F_FUNC(zbesk,ZBESK)(CADDR(z), &v,  &kode, &n, CADDR(cy_k), &nz, &ierr);
      DO_SFERR("ive(kv):", &cy_k);
      /* adjust scaling to match zbesi */
      cy_k = rotate(cy_k, -z.imag/NPY_PI);
      if (z.real > 0) {
          cy_k.real *= exp(-2*z.real);
          cy_k.imag *= exp(-2*z.real);
      }
      /* v -> -v */
      cy = rotate_i(cy, cy_k, v);
    }
  }

  return cy;
}
示例#11
0
文件: igami.c 项目: BranYang/scipy
double igamci(double a, double q)
{
    int i;
    double x, fac, f_fp, fpp_fp;

    if (npy_isnan(a) || npy_isnan(q)) {
	return NPY_NAN;
    }
    else if ((a < 0.0) || (q < 0.0) || (q > 1.0)) {
	mtherr("gammainccinv", DOMAIN);
    }
    else if (q == 0.0) {
	return NPY_INFINITY;
    }
    else if (q == 1.0) {
	return 0.0;
    }
    else if (q > 0.9) {
	return igami(a, 1 - q);
    }

    x = find_inverse_gamma(a, 1 - q, q);
    for (i = 0; i < 3; i++) {
	fac = igam_fac(a, x);
	if (fac == 0.0) {
	    return x;
	}
	f_fp = (igamc(a, x) - q) * x / (-fac);
	fpp_fp = -1.0 + (a - 1) / x;
	if (npy_isinf(fpp_fp)) {
	    x = x - f_fp;
	}
	else {
	    x = x - f_fp / (1.0 - 0.5 * f_fp * fpp_fp);
	}
    }

    return x;
}
示例#12
0
文件: ndtr.c 项目: 87/scipy
double erfc(double a)
{
double p,q,x,y,z;

if (npy_isnan(a)) {
  mtherr("erfc", DOMAIN);
  return (NPY_NAN);
}

if( a < 0.0 )
	x = -a;
else
	x = a;

if( x < 1.0 )
	return( 1.0 - erf(a) );

z = -a * a;

if( z < -MAXLOG )
	{
under:
	mtherr( "erfc", UNDERFLOW );
	if( a < 0 )
		return( 2.0 );
	else
		return( 0.0 );
	}

z = exp(z);

if( x < 8.0 )
	{
	p = polevl( x, P, 8 );
	q = p1evl( x, Q, 8 );
	}
else
	{
	p = polevl( x, R, 5 );
	q = p1evl( x, S, 6 );
	}
y = (z * p)/q;

if( a < 0 )
	y = 2.0 - y;

if( y == 0.0 )
	goto under;

return(y);
}
示例#13
0
int pbvv_wrap(double v, double x, double *pvf, double *pvd) {
  double *vv;
  double *vp;
  int num;

  if (npy_isnan(v) || npy_isnan(x)) {
    *pvf = NPY_NAN;
    *pvd = NPY_NAN;
    return 0;
  }
  /* NB. Indexing of DV/DP in specfun.f:PBVV starts from 0, hence +2 */
  num = ABS((int)v) + 2;
  vv = (double *)PyMem_Malloc(sizeof(double)*2*num);
  if (vv==NULL) {
    sf_error("pbvv", SF_ERROR_OTHER, "memory allocation error");
    *pvf = NPY_NAN;
    *pvd = NPY_NAN;
    return -1;
  }
  vp = vv + num;
  F_FUNC(pbvv,PBVV)(&v, &x, vv, vp, pvf, pvd);
  PyMem_Free(vv);
  return 0;
}
示例#14
0
文件: ndtr.c 项目: 87/scipy
double erf(double x)
{
double y, z;

if (npy_isnan(x)) {
  mtherr("erf", DOMAIN);
  return (NPY_NAN);
}

if( fabs(x) > 1.0 )
	return( 1.0 - erfc(x) );
z = x * x;

y = x * polevl( z, T, 4 ) / p1evl( z, U, 5 );
return( y );

}
示例#15
0
文件: exp10.c 项目: 317070/scipy
double exp10(double x)
{
    double px, xx;
    short n;

    if (npy_isnan(x))
	return (x);
    if (x > MAXL10) {
	return (NPY_INFINITY);
    }

    if (x < -MAXL10) {		/* Would like to use MINLOG but can't */
	mtherr("exp10", UNDERFLOW);
	return (0.0);
    }

    /* Express 10**x = 10**g 2**n
     *   = 10**g 10**( n log10(2) )
     *   = 10**( g + n log10(2) )
     */
    px = floor(LOG210 * x + 0.5);
    n = px;
    x -= px * LG102A;
    x -= px * LG102B;

    /* rational approximation for exponential
     * of the fractional part:
     * 10**x = 1 + 2x P(x**2)/( Q(x**2) - P(x**2) )
     */
    xx = x * x;
    px = x * polevl(xx, P, 3);
    x = px / (p1evl(xx, Q, 3) - px);
    x = 1.0 + ldexp(x, 1);

    /* multiply by power of 2 */
    x = ldexp(x, n);

    return (x);
}
示例#16
0
文件: exp2.c 项目: 87/scipy
double exp2(double x)
{
double px, xx;
short n;

if( npy_isnan(x) )
	return(x);
if( x > MAXL2)
	{
	return( NPY_INFINITY );
	}

if( x < MINL2 )
	{
	return(0.0);
	}

xx = x;	/* save x */
/* separate into integer and fractional parts */
px = floor(x+0.5);
n = px;
x = x - px;

/* rational approximation
 * exp2(x) = 1 +  2xP(xx)/(Q(xx) - P(xx))
 * where xx = x**2
 */
xx = x * x;
px = x * polevl( xx, P, 2 );
x =  px / ( p1evl( xx, Q, 2 ) - px );
x = 1.0 + ldexp( x, 1 );

/* scale by power of 2 */
x = ldexp( x, n );
return(x);
}
示例#17
0
int compute_ewa(size_t chan_count, int maximum_weight_mode,
        size_t swath_cols, size_t swath_rows, size_t grid_cols, size_t grid_rows, CR_TYPE *uimg, CR_TYPE *vimg,
        IMAGE_TYPE **images, IMAGE_TYPE img_fill, accum_type **grid_accums, weight_type **grid_weights, ewa_weight *ewaw, ewa_parameters *ewap) {
  // This was originally copied from a cython C file for 32-bit float inputs (that explains some of the weird parens and other syntax
  int got_point;
  unsigned int row;
  unsigned int col;
  ewa_parameters *this_ewap;
  int iu1;
  int iu2;
  int iv1;
  int iv2;
  int iu;
  int iv;
  CR_TYPE u0;
  CR_TYPE v0;
  weight_type ddq;
  weight_type dq;
  weight_type q;
  weight_type u;
  weight_type v;
  weight_type a2up1;
  weight_type au2;
  weight_type bu;
  weight_type weight;

  // Test: This is how the original fornav did its calculations
//  double u0;
//  double v0;
//  double ddq;
//  double dq;
//  double q;
//  double u;
//  double v;
//  double a2up1;
//  double au2;
//  double bu;
//  double weight;
//  double qfactor;

  int iw;
  IMAGE_TYPE this_val;
  unsigned int swath_offset;
  unsigned int grid_offset;
  size_t chan;

  got_point = 0;
  for (row = 0, swath_offset=0; row < swath_rows; row+=1) {
    for (col = 0, this_ewap = ewap; col < swath_cols; col++, this_ewap++, swath_offset++) {
      u0 = uimg[swath_offset];
      v0 = vimg[swath_offset];

      if (u0 < 0.0 || v0 < 0.0 || __isnan(u0) || npy_isnan(v0)) {
        continue;
      }

      iu1 = ((int)(u0 - this_ewap->u_del));
      iu2 = ((int)(u0 + this_ewap->u_del));
      iv1 = ((int)(v0 - this_ewap->v_del));
      iv2 = ((int)(v0 + this_ewap->v_del));

      if (iu1 < 0) {
        iu1 = 0;
      }
      if (iu2 >= grid_cols) {
        iu2 = (grid_cols - 1);
      }
      if (iv1 < 0) {
        iv1 = 0;
      }
      if (iv2 >= grid_rows) {
        iv2 = (grid_rows - 1);
      }

      if (iu1 < grid_cols && iu2 >= 0 && iv1 < grid_rows && iv2 >= 0) {
        got_point = 1;
        ddq = 2.0 * this_ewap->a;

        u = (iu1 - u0);
        a2up1 = (this_ewap->a * ((2.0 * u) + 1.0));
        bu = this_ewap->b * u;
        au2 = this_ewap->a * u * u;

        for (iv = iv1; iv <= iv2; iv++) {
          v = (iv - v0);
          dq = (a2up1 + (this_ewap->b * v));
          q = ((((this_ewap->c * v) + bu) * v) + au2);
          for (iu = iu1; iu <= iu2; iu++) {
            if ((q >= 0.0) && (q < this_ewap->f)) {
              iw = ((int)(q * ewaw->qfactor));
              if (iw >= ewaw->count) {
                iw = (ewaw->count - 1);
              }
              weight = (ewaw->wtab[iw]);
              grid_offset = ((iv * grid_cols) + iu);

              for (chan = 0; chan < chan_count; chan+=1) {
                this_val = ((images[chan])[swath_offset]);
                if (maximum_weight_mode) {
                  if (weight > grid_weights[chan][grid_offset]) {
                    ((grid_weights[chan])[grid_offset]) = weight;
                    if ((this_val == img_fill) || (__isnan(this_val))) {
                      ((grid_accums[chan])[grid_offset]) = (accum_type)NPY_NANF;
                    } else {
                      ((grid_accums[chan])[grid_offset]) = (accum_type)this_val;
                    }
                  }
                } else {
                  if ((this_val != img_fill) && !(__isnan(this_val))) {
                    ((grid_weights[chan])[grid_offset]) += weight;
                    ((grid_accums[chan])[grid_offset]) += (accum_type)this_val * weight;
                  }
                }
              }
            }
            q += dq;
            dq += ddq;
          }
        }
      }
    }
  }

  /* function exit code */
  return got_point;
}
示例#18
0
NPY_NO_EXPORT PyObject *
arr_interp(PyObject *NPY_UNUSED(self), PyObject *args, PyObject *kwdict)
{

    PyObject *fp, *xp, *x;
    PyObject *left = NULL, *right = NULL;
    PyArrayObject *afp = NULL, *axp = NULL, *ax = NULL, *af = NULL;
    npy_intp i, lenx, lenxp;
    npy_double lval, rval;
    const npy_double *dy, *dx, *dz;
    npy_double *dres, *slopes = NULL;

    static char *kwlist[] = {"x", "xp", "fp", "left", "right", NULL};

    NPY_BEGIN_THREADS_DEF;

    if (!PyArg_ParseTupleAndKeywords(args, kwdict, "OOO|OO", kwlist,
                                     &x, &xp, &fp, &left, &right)) {
        return NULL;
    }

    afp = (PyArrayObject *)PyArray_ContiguousFromAny(fp, NPY_DOUBLE, 1, 1);
    if (afp == NULL) {
        return NULL;
    }
    axp = (PyArrayObject *)PyArray_ContiguousFromAny(xp, NPY_DOUBLE, 1, 1);
    if (axp == NULL) {
        goto fail;
    }
    ax = (PyArrayObject *)PyArray_ContiguousFromAny(x, NPY_DOUBLE, 1, 0);
    if (ax == NULL) {
        goto fail;
    }
    lenxp = PyArray_SIZE(axp);
    if (lenxp == 0) {
        PyErr_SetString(PyExc_ValueError,
                "array of sample points is empty");
        goto fail;
    }
    if (PyArray_SIZE(afp) != lenxp) {
        PyErr_SetString(PyExc_ValueError,
                "fp and xp are not of the same length.");
        goto fail;
    }

    af = (PyArrayObject *)PyArray_SimpleNew(PyArray_NDIM(ax),
                                            PyArray_DIMS(ax), NPY_DOUBLE);
    if (af == NULL) {
        goto fail;
    }
    lenx = PyArray_SIZE(ax);

    dy = (const npy_double *)PyArray_DATA(afp);
    dx = (const npy_double *)PyArray_DATA(axp);
    dz = (const npy_double *)PyArray_DATA(ax);
    dres = (npy_double *)PyArray_DATA(af);
    /* Get left and right fill values. */
    if ((left == NULL) || (left == Py_None)) {
        lval = dy[0];
    }
    else {
        lval = PyFloat_AsDouble(left);
        if ((lval == -1) && PyErr_Occurred()) {
            goto fail;
        }
    }
    if ((right == NULL) || (right == Py_None)) {
        rval = dy[lenxp - 1];
    }
    else {
        rval = PyFloat_AsDouble(right);
        if ((rval == -1) && PyErr_Occurred()) {
            goto fail;
        }
    }

    /* binary_search_with_guess needs at least a 3 item long array */
    if (lenxp == 1) {
        const npy_double xp_val = dx[0];
        const npy_double fp_val = dy[0];

        NPY_BEGIN_THREADS_THRESHOLDED(lenx);
        for (i = 0; i < lenx; ++i) {
            const npy_double x_val = dz[i];
            dres[i] = (x_val < xp_val) ? lval :
                                         ((x_val > xp_val) ? rval : fp_val);
        }
        NPY_END_THREADS;
    }
    else {
        npy_intp j = 0;

        /* only pre-calculate slopes if there are relatively few of them. */
        if (lenxp <= lenx) {
            slopes = PyArray_malloc((lenxp - 1) * sizeof(npy_double));
            if (slopes == NULL) {
                goto fail;
            }
        }

        NPY_BEGIN_THREADS;

        if (slopes != NULL) {
            for (i = 0; i < lenxp - 1; ++i) {
                slopes[i] = (dy[i+1] - dy[i]) / (dx[i+1] - dx[i]);
            }
        }

        for (i = 0; i < lenx; ++i) {
            const npy_double x_val = dz[i];

            if (npy_isnan(x_val)) {
                dres[i] = x_val;
                continue;
            }

            j = binary_search_with_guess(x_val, dx, lenxp, j);
            if (j == -1) {
                dres[i] = lval;
            }
            else if (j == lenxp) {
                dres[i] = rval;
            }
            else if (j == lenxp - 1) {
                dres[i] = dy[j];
            }
            else {
                const npy_double slope = (slopes != NULL) ? slopes[j] :
                                         (dy[j+1] - dy[j]) / (dx[j+1] - dx[j]);
                dres[i] = slope*(x_val - dx[j]) + dy[j];
            }
        }

        NPY_END_THREADS;
    }

    PyArray_free(slopes);
    Py_DECREF(afp);
    Py_DECREF(axp);
    Py_DECREF(ax);
    return (PyObject *)af;

fail:
    Py_XDECREF(afp);
    Py_XDECREF(axp);
    Py_XDECREF(ax);
    Py_XDECREF(af);
    return NULL;
}
示例#19
0
double npy_atan2(double y, double x)
{
    npy_int32 k, m, iy, ix, hx, hy;
    npy_uint32 lx,ly;
    double z;

    EXTRACT_WORDS(hx, lx, x);
    ix = hx & 0x7fffffff;
    EXTRACT_WORDS(hy, ly, y);
    iy = hy & 0x7fffffff;

    /* if x or y is nan, return nan */
    if (npy_isnan(x * y)) {
        return x + y;
    }

    if (x == 1.0) {
        return npy_atan(y);
    }

    m = 2 * npy_signbit(x) + npy_signbit(y);
    if (y == 0.0) {
        switch(m) {
        case 0:
        case 1: return  y;  /* atan(+-0,+anything)=+-0 */
        case 2: return  NPY_PI;/* atan(+0,-anything) = pi */
        case 3: return -NPY_PI;/* atan(-0,-anything) =-pi */
        }
    }

    if (x == 0.0) {
        return y > 0 ? NPY_PI_2 : -NPY_PI_2;
    }

    if (npy_isinf(x)) {
        if (npy_isinf(y)) {
            switch(m) {
                case 0: return  NPY_PI_4;/* atan(+INF,+INF) */
                case 1: return -NPY_PI_4;/* atan(-INF,+INF) */
                case 2: return  3.0*NPY_PI_4;/*atan(+INF,-INF)*/
                case 3: return -3.0*NPY_PI_4;/*atan(-INF,-INF)*/
            }
        } else {
            switch(m) {
                case 0: return  NPY_PZERO;  /* atan(+...,+INF) */
                case 1: return  NPY_NZERO;  /* atan(-...,+INF) */
                case 2: return  NPY_PI;  /* atan(+...,-INF) */
                case 3: return -NPY_PI;  /* atan(-...,-INF) */
            }
        }
    }

    if (npy_isinf(y)) {
        return y > 0 ? NPY_PI_2 : -NPY_PI_2;
    }

    /* compute y/x */
    k = (iy - ix) >> 20;
    if (k > 60) {            /* |y/x| >  2**60 */
        z = NPY_PI_2 + 0.5 * NPY_DBL_EPSILON;
        m &= 1;
    } else if (hx < 0 && k < -60) {
        z = 0.0;    /* 0 > |y|/x > -2**-60 */
    } else {
        z = npy_atan(npy_fabs(y/x));        /* safe to do y/x */
    }

    switch (m) {
        case 0: return  z  ;    /* atan(+,+) */
        case 1: return -z  ;    /* atan(-,+) */
        case 2: return  NPY_PI - (z - NPY_DBL_EPSILON);/* atan(+,-) */
        default: /* case 3 */
            return  (z - NPY_DBL_EPSILON) - NPY_PI;/* atan(-,-) */
    }
}
示例#20
0
template<typename IMAGE_TYPE> int __isnan(IMAGE_TYPE x) {
    // Return numpy's isnan for normal float arguments (see __isnan below for ints)
    return npy_isnan(x);
}