Function complex_conj

monai/apps/reconstruction/complex_utils.py:208–233

Compute complex conjugate of an/a array/tensor. Supports Ndim inputs with last dim equal to 2 (real/imaginary channels) Args: x: Input array/tensor with 2 channels in the last dimension representing real and imaginary parts. Returns: Complex conjugate of x Example

(x: NdarrayOrTensor)

def complex_conj(x: NdarrayOrTensor) -> NdarrayOrTensor:
    """
    Compute complex conjugate of an/a array/tensor. Supports Ndim inputs with last dim equal to 2 (real/imaginary channels)

    Args:
        x: Input array/tensor with 2 channels in the last dimension representing real and imaginary parts.

    Returns:
        Complex conjugate of x

    Example:
        .. code-block:: python

            import numpy as np
            x = np.array([[1,2],[3,4]])
            # the following line prints array([[ 1, -2], [ 3, -4]])
            print(complex_conj(x))
    """
    if x.shape[-1] != 2:
        raise ValueError(f"last dim must be 2, but x.shape[-1] is {x.shape[-1]}.")

    if isinstance(x, Tensor):
        return complex_conj_t(x)
    else:
        np_conj: np.ndarray = np.stack((x[..., 0], -x[..., 1]), axis=-1)
        return np_conj