Source code for bed_reader._to_bed

import contextlib
import logging
import os
from pathlib import Path
from typing import Any, List, Mapping, Optional, Union

import numpy as np

from bed_reader import get_num_threads, open_bed

from .bed_reader import (  # type: ignore
    encode1_f32,
    encode1_f64,
    encode1_i8,
    write_f32,
    write_f64,
    write_i8,
)


[docs] class create_bed: """Open a file to write values into PLINK .bed format. Values may be given in a SNP-by-SNP (or individual-by-individual) manner. For large datasets, `create_bed` requires less memory than :func:`to_bed`. Parameters ---------- location: pathlib.Path or str, optional local .bed file to create. iid_count: int: The number of individuals (samples). sid_count: int: The number of SNPs (variants). properties: dict, optional A dictionary of property names and values to write to the .fam and .bim files. Any properties not mentioned will be filled in with default values. The possible property names are: "fid" (family id), "iid" (individual or sample id), "father" (father id), "mother" (mother id), "sex", "pheno" (phenotype), "chromosome", "sid" (SNP or variant id), "cm_position" (centimorgan position), "bp_position" (base-pair position), "allele_1", "allele_2". The values are lists or arrays. See example, below. count_A1: bool, optional True (default) to count the number of A1 alleles (the PLINK standard). False to count the number of A2 alleles. fam_location: pathlib.Path or str, optional Path to the file containing information about each individual (sample). Defaults to replacing the .bed file’s suffix with .fam. bim_location: pathlib.Path or str, optional Path to the file containing information about each SNP (variant). Defaults to replacing the .bed file’s suffix with .bim. major: str, optional Use "SNP" (default) to write the file is usual SNP-major mode. This makes reading the data SNP-by-SNP faster. Use "individual" to write the file in the uncommon individual-major mode. force_python_only If False (default), uses the faster Rust helper functions; otherwise it uses the slower pure Python code. num_threads: None or int, optional Not currently used. create_bed Errors ----------------- Raises an error if you write the wrong number of vectors or if any vector has the wrong length. Also, all vector values must be 0, 1, 2, or missing. If floats, missing is ``np.nan``. If integers, missing is -127. Behind the scenes, `create_bed` first creates a temporary bed file. At the end, if there are no errors, it renames the temporary file to the final file name. This helps prevent creation of corrupted files. Examples -------- In this example, all properties are given and we write the data out SNP-by-SNP. The data is floats. .. doctest:: >>> import numpy as np >>> from bed_reader import create_bed, tmp_path >>> >>> output_file = tmp_path() / "small.bed" >>> properties = { ... "fid": ["fid1", "fid1", "fid2"], ... "iid": ["iid1", "iid2", "iid3"], ... "father": ["iid23", "iid23", "iid22"], ... "mother": ["iid34", "iid34", "iid33"], ... "sex": [1, 2, 0], ... "pheno": ["red", "red", "blue"], ... "chromosome": ["1", "1", "5", "Y"], ... "sid": ["sid1", "sid2", "sid3", "sid4"], ... "cm_position": [100.4, 2000.5, 4000.7, 7000.9], ... "bp_position": [1, 100, 1000, 1004], ... "allele_1": ["A", "T", "A", "T"], ... "allele_2": ["A", "C", "C", "G"], ... } >>> with create_bed(output_file, iid_count=3, sid_count=4, properties=properties) as bed_writer: ... bed_writer.write([1.0, 2.0, 0.0]) ... bed_writer.write([0.0, 0.0, 1.0]) ... bed_writer.write([np.nan, np.nan, 2.0]) ... bed_writer.write([0.0, 2.0, 0.0]) In this next example, no properties are given, so default values are assigned. Also, we write out ints. Finally, we write the same data out as above, but individual-by-individual. If we then read the new file and list the chromosome property, it is an array of '0's, the default chromosome value. .. doctest:: >>> output_file2 = tmp_path() / "small2.bed" >>> with create_bed(output_file2, iid_count=3, sid_count=4, major="individual") as bed_writer: # noqa: E501 ... bed_writer.write([1, 0, -127, 0]) ... bed_writer.write([2, 0, -127, 2]) ... bed_writer.write([0, 1, 2, 0]) >>> >>> from bed_reader import open_bed >>> with open_bed(output_file2) as bed2: ... print(bed2.chromosome) ['0' '0' '0' '0'] """ def __init__( self, location: Union[str, Path], iid_count: int, sid_count: int, properties: Mapping[str, List[Any]] = {}, count_A1: bool = True, fam_location: Optional[Union[str, Path]] = None, bim_location: Optional[Union[str, Path]] = None, major: str = "SNP", force_python_only: bool = False, num_threads=None, ) -> None: self.location = Path(location) self.iid_count = iid_count self.sid_count = sid_count self.count_A1 = count_A1 self.force_python_only = force_python_only self.num_threads = num_threads or os.cpu_count() if major == "SNP": self.major_count = sid_count self.minor_count = iid_count elif major == "individual": self.major_count = iid_count self.minor_count = sid_count else: msg = f"major must be 'SNP' or 'individual', not '{major}'" raise ValueError(msg) self.major = major self.minor_count_div4 = (self.minor_count - 1) // 4 + 1 self.buffer = np.zeros(self.minor_count_div4, dtype=np.uint8) if not count_A1: self.zero_code = 0b00 self.two_code = 0b11 else: self.zero_code = 0b11 self.two_code = 0b00 fam_location = ( Path(fam_location) if fam_location is not None else self._replace_extension(self.location, "fam") ) bim_location = ( Path(bim_location) if bim_location is not None else self._replace_extension(self.location, "bim") ) properties, _ = open_bed._fix_up_properties( properties, iid_count, sid_count, use_fill_sequence=True, ) open_bed._write_fam_or_bim(self.location, properties, "fam", fam_location) open_bed._write_fam_or_bim(self.location, properties, "bim", bim_location) self.temp_filepath = self.location.with_suffix(".bed_temp") self.file_pointer = open(self.temp_filepath, "wb") # see http://zzz.bwh.harvard.edu/plink/binary.shtml self.file_pointer.write(bytes(bytearray([0b01101100]))) # magic numbers self.file_pointer.write(bytes(bytearray([0b00011011]))) # magic numbers if self.major == "SNP": self.file_pointer.write(bytes(bytearray([0b00000001]))) # snp major else: assert self.major == "individual" # real assert self.file_pointer.write(bytes(bytearray([0b00000000]))) self.write_count = 0 if os.path.exists(self.location): os.unlink(self.location) def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.close()
[docs] def close(self) -> None: """Close the bed_writer, writing the file to disk. If you use :class:`create_bed` with the `with` statement, you don't need to use this. See :class:`create_bed` for more information. """ if self.file_pointer is not None: try: self.file_pointer.close() self.file_pointer = None if self.write_count != self.major_count: msg = ( f"Attempt to write fewer vectors ({self.write_count}) " f"than expected ({self.major_count})" ) raise ValueError( msg, ) os.rename(self.temp_filepath, self.location) except Exception: self._clean_up_error() raise else: self._clean_up_error()
def _clean_up_error(self) -> None: with contextlib.suppress(Exception): os.unlink(self.temp_filepath) @staticmethod def _replace_extension(location, extension): if open_bed._is_url(location): return location.parent / (location.stem + "." + extension) return None
[docs] def write(self, vector) -> None: """Write a vector of values to the bed_writer. See :class:`create_bed` for more information. """ if self.file_pointer is None: msg = "Attempt to write after file was closed for writing." raise RuntimeError(msg) try: self.write_count += 1 if self.write_count > self.major_count: msg = ( f"Attempt to write more vectors ({self.write_count}) " f"than expected ({self.major_count})" ) raise ValueError( msg, ) vector = _fix_up_vector(vector) if len(vector) != self.minor_count: msg = f"Expected vector to {self.minor_count} values, got {len(vector)} instead" raise ValueError( msg, ) self._internal_write(vector) except Exception: self.file_pointer.close() self.file_pointer = None # Prevent further writes raise # Re-raise the exception to handle it externally
def _internal_write(self, vector) -> None: if not self.force_python_only: if vector.dtype == np.int8: encode1_i8(self.count_A1, vector, self.buffer, self.num_threads) elif vector.dtype == np.float32: encode1_f32(self.count_A1, vector, self.buffer, self.num_threads) elif vector.dtype == np.float64: encode1_f64(self.count_A1, vector, self.buffer, self.num_threads) else: msg = ( f"dtype '{vector.dtype}' not known, only 'int8', 'float32', " f"and 'float64' are allowed." ) raise ValueError( msg, ) self.file_pointer.write(self.buffer) else: for minor_by_four in range(0, self.minor_count, 4): vals_for_this_byte = vector[minor_by_four : minor_by_four + 4] byte = 0b00000000 for val_index in range(len(vals_for_this_byte)): val_for_byte = vals_for_this_byte[val_index] if val_for_byte == 0: code = self.zero_code elif val_for_byte == 1: code = 0b10 # backwards on purpose elif val_for_byte == 2: code = self.two_code elif (vector.dtype == np.int8 and val_for_byte == -127) or np.isnan( val_for_byte, ): code = 0b01 # backwards on purpose else: raise ValueError( "Attempt to write illegal value to .bed file. " + "Only 0,1,2,missing allowed.", ) byte |= code << (val_index * 2) # This is writing one byte at a time self.file_pointer.write(bytes(bytearray([byte])))
def _fix_up_vector(input): if not isinstance(input, np.ndarray): return _fix_up_vector(np.array(input)) if np.issubdtype(input.dtype, np.integer) and input.dtype != np.int8: return _fix_up_vector(np.array(input, dtype=np.int8)) if np.issubdtype(input.dtype, np.floating) and input.dtype not in ( np.float32, np.float64, ): return _fix_up_vector(np.array(input, dtype=np.float32)) if len(input.shape) != 1: msg = "vector should be one dimensional" raise ValueError(msg) return input
[docs] def to_bed( filepath: Union[str, Path], val: np.ndarray, properties: Mapping[str, List[Any]] = {}, count_A1: bool = True, fam_filepath: Optional[Union[str, Path]] = None, bim_filepath: Optional[Union[str, Path]] = None, major: str = "SNP", force_python_only: bool = False, num_threads=None, ) -> None: """Write values to a file in PLINK .bed format. If your data is too large to fit in memory, use :class:`create_bed` instead. Parameters ---------- filepath: .bed file to write to. val: array-like: A two-dimension array (or array-like object) of values. The values should be (or be convertible to) all floats or all integers. The values should be 0, 1, 2, or missing. If floats, missing is ``np.nan``. If integers, missing is -127. properties: dict, optional A dictionary of property names and values to write to the .fam and .bim files. Any properties not mentioned will be filled in with default values. The possible property names are: "fid" (family id), "iid" (individual or sample id), "father" (father id), "mother" (mother id), "sex", "pheno" (phenotype), "chromosome", "sid" (SNP or variant id), "cm_position" (centimorgan position), "bp_position" (base-pair position), "allele_1", "allele_2". The values are lists or arrays. See example, below. count_A1: bool, optional True (default) to count the number of A1 alleles (the PLINK standard). False to count the number of A2 alleles. fam_filepath: pathlib.Path or str, optional Path to the file containing information about each individual (sample). Defaults to replacing the .bed file’s suffix with .fam. bim_filepath: pathlib.Path or str, optional Path to the file containing information about each SNP (variant). Defaults to replacing the .bed file’s suffix with .bim. major: str, optional Use "SNP" (default) to write the file is usual SNP-major mode. This makes reading the data SNP-by-SNP faster. Use "individual" to write the file in the uncommon individual-major mode. force_python_only If False (default), uses the faster Rust helper functions; otherwise it uses the slower pure Python code. num_threads: None or int, optional The number of threads with which to write data. Defaults to all available processors. Can also be set with these environment variables (listed in priority order): 'PST_NUM_THREADS', 'NUM_THREADS', 'MKL_NUM_THREADS'. Examples -------- In this example, all properties are given. .. doctest:: >>> import numpy as np >>> from bed_reader import to_bed, tmp_path >>> >>> output_file = tmp_path() / "small.bed" >>> val = [[1.0, 0.0, np.nan, 0.0], ... [2.0, 0.0, np.nan, 2.0], ... [0.0, 1.0, 2.0, 0.0]] >>> properties = { ... "fid": ["fid1", "fid1", "fid2"], ... "iid": ["iid1", "iid2", "iid3"], ... "father": ["iid23", "iid23", "iid22"], ... "mother": ["iid34", "iid34", "iid33"], ... "sex": [1, 2, 0], ... "pheno": ["red", "red", "blue"], ... "chromosome": ["1", "1", "5", "Y"], ... "sid": ["sid1", "sid2", "sid3", "sid4"], ... "cm_position": [100.4, 2000.5, 4000.7, 7000.9], ... "bp_position": [1, 100, 1000, 1004], ... "allele_1": ["A", "T", "A", "T"], ... "allele_2": ["A", "C", "C", "G"], ... } >>> to_bed(output_file, val, properties=properties) Here, no properties are given, so default values are assigned. If we then read the new file and list the chromosome property, it is an array of '0's, the default chromosome value. .. doctest:: >>> output_file2 = tmp_path() / "small2.bed" >>> val = [[1, 0, -127, 0], [2, 0, -127, 2], [0, 1, 2, 0]] >>> to_bed(output_file2, val) >>> >>> from bed_reader import open_bed >>> with open_bed(output_file2) as bed2: ... print(bed2.chromosome) ['0' '0' '0' '0'] """ filepath = Path(filepath) val = _fix_up_val(val) iid_count = val.shape[0] sid_count = val.shape[1] if major == "SNP": major_count = sid_count minor_count = iid_count elif major == "individual": major_count = iid_count minor_count = sid_count else: msg = f"major must be 'SNP' or 'individual', not '{major}'" raise ValueError(msg) properties, _ = open_bed._fix_up_properties( properties, iid_count=iid_count, sid_count=sid_count, use_fill_sequence=True, ) open_bed._write_fam_or_bim(filepath, properties, "fam", fam_filepath) open_bed._write_fam_or_bim(filepath, properties, "bim", bim_filepath) if not force_python_only: if not val.flags["C_CONTIGUOUS"] and not val.flags["F_CONTIGUOUS"]: msg = "val must be contiguous." raise ValueError(msg) num_threads = get_num_threads(num_threads) if major == "individual": val = val.T try: if val.dtype == np.float64: write_f64( str(filepath), is_a1_counted=count_A1, val=val, num_threads=num_threads, ) elif val.dtype == np.float32: write_f32( str(filepath), is_a1_counted=count_A1, val=val, num_threads=num_threads, ) elif val.dtype == np.int8: write_i8( str(filepath), is_a1_counted=count_A1, val=val, num_threads=num_threads, ) else: raise ValueError( f"dtype '{val.dtype}' not known, only " + "'int8', 'float32', and 'float64' are allowed.", ) if major == "individual": # change the 3rd byte in the file to 0b00000000 with open(filepath, "r+b") as bed_filepointer: bed_filepointer.seek(2) bed_filepointer.write(bytes(bytearray([0b00000000]))) except SystemError as system_error: with contextlib.suppress(Exception): os.unlink(filepath) raise system_error.__cause__ else: if not count_A1: zero_code = 0b00 two_code = 0b11 else: zero_code = 0b11 two_code = 0b00 with open(filepath, "wb") as bed_filepointer: # see http://zzz.bwh.harvard.edu/plink/binary.shtml bed_filepointer.write(bytes(bytearray([0b01101100]))) # magic numbers bed_filepointer.write(bytes(bytearray([0b00011011]))) # magic numbers if major == "SNP": bed_filepointer.write(bytes(bytearray([0b00000001]))) # snp major else: assert major == "individual" bed_filepointer.write( bytes(bytearray([0b00000000])), ) # individual major for major_index in range(major_count): if major_index % 1 == 0: logging.info( f"Writing {major} # {major_index} to file '{filepath}'", ) if major == "SNP": vector = val[:, major_index] else: assert major == "individual" vector = val[major_index, :] for minor_by_four in range(0, minor_count, 4): vals_for_this_byte = vector[minor_by_four : minor_by_four + 4] byte = 0b00000000 for val_index in range(len(vals_for_this_byte)): val_for_byte = vals_for_this_byte[val_index] if val_for_byte == 0: code = zero_code elif val_for_byte == 1: code = 0b10 # backwards on purpose elif val_for_byte == 2: code = two_code elif ( val.dtype == np.int8 and val_for_byte == -127 ) or np.isnan(val_for_byte): code = 0b01 # backwards on purpose else: raise ValueError( "Attempt to write illegal value to .bed file. " + "Only 0,1,2,missing allowed.", ) byte |= code << (val_index * 2) bed_filepointer.write(bytes(bytearray([byte]))) logging.info(f"Done writing {filepath}")
def _fix_up_val(input): if not isinstance(input, np.ndarray): return _fix_up_val(np.array(input)) if np.issubdtype(input.dtype, np.integer) and input.dtype != np.int8: return _fix_up_val(np.array(input, dtype=np.int8)) if np.issubdtype(input.dtype, np.floating) and input.dtype not in ( np.float32, np.float64, ): return _fix_up_val(np.array(input, dtype=np.float32)) if len(input.shape) != 2: msg = "val should be two dimensional" raise ValueError(msg) return input # if __name__ == "__main__": # logging.basicConfig(level=logging.INFO) # import pytest # pytest.main(["--doctest-modules", __file__])