def _create_singleframe_bvals_bvecs(grouped_dicoms, bval_file, bvec_file, nifti, nifti_file):
    """
    Write the bvals from the sorted dicom files to a bval file
    """

    # create the empty arrays
    bvals = numpy.zeros([len(grouped_dicoms)], dtype=numpy.int32)
    bvecs = numpy.zeros([len(grouped_dicoms), 3])

    # loop over all timepoints and create a list with all bvals and bvecs
    if _is_bval_type_a(grouped_dicoms):
        bval_tag = Tag(0x2001, 0x1003)
        bvec_x_tag = Tag(0x2005, 0x10b0)
        bvec_y_tag = Tag(0x2005, 0x10b1)
        bvec_z_tag = Tag(0x2005, 0x10b2)
        for stack_index in range(0, len(grouped_dicoms)):
            bvals[stack_index] = common.get_fl_value(grouped_dicoms[stack_index][0][bval_tag])
            bvecs[stack_index, :] = [common.get_fl_value(grouped_dicoms[stack_index][0][bvec_x_tag]),
                                     common.get_fl_value(grouped_dicoms[stack_index][0][bvec_y_tag]),
                                     common.get_fl_value(grouped_dicoms[stack_index][0][bvec_z_tag])]
    elif _is_bval_type_b(grouped_dicoms):
        bval_tag = Tag(0x0018, 0x9087)
        bvec_tag = Tag(0x0018, 0x9089)
        for stack_index in range(0, len(grouped_dicoms)):
            bvals[stack_index] = common.get_fd_value(grouped_dicoms[stack_index][0][bval_tag])
            bvecs[stack_index, :] = common.get_fd_array_value(grouped_dicoms[stack_index][0][bvec_tag], 3)

    # truncate nifti if needed
    nifti, bvals, bvecs = _fix_diffusion_images(bvals, bvecs, nifti, nifti_file)

    # save the found bvecs to the file
    if numpy.count_nonzero(bvals) > 0 or numpy.count_nonzero(bvecs) > 0:
        common.write_bval_file(bvals, bval_file)
        common.write_bvec_file(bvecs, bvec_file)
    else:
        bval_file = None
        bvec_file = None
        bvals = None
        bvecs = None
    return nifti, bvals, bvecs, bval_file, bvec_file
Write the bvals from the sorted dicom files to a bval file