Name

taucs_chinfo — get information on Cholesky factors

Calling Sequence

[OK, n, cnz] = taucs_chinfo(C_ptr)

Parameters

C_ptr

a pointer to a Cholesky factorization

OK

a scalar boolean

n

a scalar integer

cnz

a scalar integer

Description

This function may be used to know basic information about the Cholesky factor created with taucs_chfact :

  • first OK is %t if C_ptr is a valid pointer to an Cholesky factorization (and %f else)

  • if OK is %t then n and cnz are respectively the matrix order and the number of non zeros elements in the supernodal structure storing C ; if OK is %f, n and cnz are set to the void matrix [].

Details

Due to the supernodal structure used for C, cnz is larger than the exact number of non-zeros elements in C (and so this cnz is a mesure of the memory used internally). To get the exact cnz you may retrieve the Cholesky factor with taucs_chget then apply the nnz scilab function (see the 2d example in taucs_chget).

See Also

taucs_chfact , taucs_chsolve , taucs_chdel , taucs_chget

Authors

taucs by Sivan Toledo (see taucs_license)
scilab interface by Bruno Pincon