#!/usr/bin/env python
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from numpy import (half, float32, asarray, ndarray,
                   longdouble, float64, longcomplex, complex_)

__all__ = ['__upcast_float16_array', '__downcast_float128_array']

def __upcast_float16_array(x):
    """
    Used in _scipy_fft to upcast float16 to float32, 
    instead of float64, as mkl_fft would do"""
    if hasattr(x, "dtype"):
        xdt = x.dtype
        if xdt == half:
            # no half-precision routines, so convert to single precision
            return asarray(x, dtype=float32)
        if xdt == longdouble and not xdt == float64:
            raise ValueError("type %s is not supported" % xdt)
    if not isinstance(x, ndarray):
        __x = asarray(x)
        xdt = __x.dtype
        if xdt == half:
            # no half-precision routines, so convert to single precision
            return asarray(__x, dtype=float32)
        if xdt == longdouble and not xdt == float64:
            raise ValueError("type %s is not supported" % xdt)
        return __x
    return x


def __downcast_float128_array(x):
    """
    Used in _numpy_fft to unsafely downcast float128/complex256 to 
    complex128, instead of raising an error"""
    if hasattr(x, "dtype"):
        xdt = x.dtype
        if xdt == longdouble and not xdt == float64:
            return asarray(x, dtype=float64)
        elif xdt == longcomplex and not xdt == complex_:
            return asarray(x, dtype=complex_)
    if not isinstance(x, ndarray):
        __x = asarray(x)
        xdt = __x.dtype
        if xdt == longdouble and not xdt == float64:
            return asarray(x, dtype=float64)
        elif xdt == longcomplex and not xdt == complex_:
            return asarray(x, dtype=complex_)
        return __x
    return x