Function

NumCosmoMathlapack_dptsv

Declaration [src] 

gint
ncm_lapack_dptsv (
  gdouble* d,
  gdouble* e,
  gdouble* b,
  gdouble* x,
  gint n
)

Description [src]

This function computes the solution to a real system of linear equations $A*X = B$ (B = b), where $A$ is an N-by-N (N = n) symmetric positive definite tridiagonal matrix, and $X$ and $B$ are N-by-NRHS (NRHS = 1) matrices.

$A$ is factored as $A = LDL^T$, and the factored form of $A$ is then used to solve the system of equations.

Parameters

d

Type: gdouble*

Array of doubles with dimension n.

The data is owned by the caller of the function.
e

Type: gdouble*

Array of doubles with dimension n -1.

The data is owned by the caller of the function.
b

Type: gdouble*

Array of doubles with dimension n.

The data is owned by the caller of the function.
x

Type: gdouble*

Array of doubles with dimension n.

The data is owned by the caller of the function.
n

Type: gint

The order of the matrix $A$ (>= 0).

Return value

Type: gint

I = 0: successful exit

   < 0:  -i, the i-th argument had an illegal value

   > 0:   i, the leading minor of order i is not
          positive definite, and the solution has not been
          computed.  The factorization has not been completed
          unless i = N.