getgenotypesraw: fetch genotype integer matrix for specified markers
In Mega2R: Accessing and Processing a 'Mega2' Genetic Database

Description Usage Arguments Details Value Examples

This function calls a C++ function that does all the heavy lifting. It passes the arguments necessary for the C++ function: some from the caller's arguments and some from data frames that are in the "global" environment, envir. From its markers_arg argument, it gets the locus_index and the index in the unified_genotype_table. From the "global" environment, envir, it gets a bit vector of compressed genotype information, and some bookkeeping related data. Note: This function also contains a dispatch/switch on the type of compression in the genotype vector. A different C++ function is called when there is compression versus when there is no compression.

1	getgenotypesraw(markers_arg, envir = ENV)

markers_arg

a data.frame with the following 5 observations:

locus_link: is the ordinal ranking of this marker among all loci
locus_link_fill: is the position of corresponding genotype data in the unified_genotype_table
MarkerName: is the text name of the marker
chromosome: is the integer chromosome number
position: is the integer base pair position of marker

envir

an environment that contains all the data frames created from the SQLite database.

The unified_genotype_table contains one raw vector for each person. In the vector, there are two bits for each genotype. This function creates an output matrix by fixing the marker and collecting genotype information for each person and then repeating for all the needed markers.

a matrix of genotypes represented as integers. Each 32 bit integer represents contains two allele values: the high 16 bits contains the index of allele1 and the low 16 bits contains the index of allele2. In the matrix, there is one column for each marker in the markers_arg argument. There is one row for each person in the family (fam) table.

db = system.file("exdata", "seqsimm.db", package="Mega2R")
ENV = read.Mega2DB(db)

# two ints in upper/lower half integer representing allele # for all persons in chromosome 1
getgenotypesraw(ENV$markers[ENV$markers$chromosome == 1,])