[−][src]Function libisal_sys::gf_gen_rs_matrix
pub unsafe extern "C" fn gf_gen_rs_matrix(a: *mut c_uchar, m: c_int, k: c_int)
Generate a matrix of coefficients to be used for encoding.
Vandermonde matrix example of encoding coefficients where high portion of
matrix is identity matrix I and lower portion is constructed as 2^{i*(j-k+1)}
i:{0,k-1} j:{k,m-1}. Commonly used method for choosing coefficients in
erasure encoding but does not guarantee invertable for every sub matrix. For
large pairs of m and k it is possible to find cases where the decode matrix
chosen from sources and parity is not invertable. Users may want to adjust
for certain pairs m and k. If m and k satisfy one of the following
inequalities, no adjustment is required:
k <= 3k = 4, m <= 25k = 5, m <= 10k <= 21, m-k = 4m - k <= 3
Arguments:
a:[m x k]array to hold coefficientsm: number of rows in matrix corresponding to srcs + parity.k: number of columns in matrix corresponding to srcs.