c++ - Confused with pdpotrf arguments -

i want cholesky factorization in distributed environment. purpose, use pdpotrf(). however, struggling understanding parameters needed function , provide no c example on how use (and example great have).

assume have nxx matrix want factorize. then, values should parameters have? uplo, a , info defined in mind. how rest?

n should equal n say. however, desca, ia , ja ones confuse me. moreover, desca global , local, can't understand. can explain? maybe approach-example (not code, since want understand, not copy paste).

_{i not know fortran.}

from answer, have:

ia , ja: parameters meant provide starting row , column of global matrix inside larger matrix. relevant if have big matrix , want cholesky decomp of submatrix. in case, ia , ja both have 1!

again, answer, there exists link, describes desca: