- A
- (
*input/output)***REAL**or**COMPLEX**square array, shape .

On entry, the matrix or its equilibration:

If**UPLO**= 'U', then the upper triangular part of**A**contains the upper triangular part of (the equilibrated) , and the strictly lower triangular part of**A**is not referenced.

If**UPLO**= 'L', then the lower triangular part of**A**contains the lower triangular part of (the equilibrated) , and the strictly upper triangular part of**A**is not referenced.

If**FACT**= 'F' and**EQUED**= 'Y', then has been equilibrated by the scaling factors in**S**during a previous call to**LA_POSVX**.

On exit, if 'E', then the equilibrated version of is stored in**A**; otherwise, is unchanged. - B
- (
*input/output*)**REAL**or**COMPLEX**array, shape with or shape with .

On entry, the matrix .

On exit, the scaled version of if the system has been equilibrated; otherwise, is unchanged. - X
- (
*output*)**REAL**or**COMPLEX**array, shape with and , or shape with .

The solution matrix . - UPLO
*Optional*(*input)***CHARACTER(LEN=1)**.

Default value: 'U'.- AF
*Optional*(*input*or*output)***REAL**or**COMPLEX**array, shape with the same size as**A**.

If**FACT**'F' then**AF**is an*input*argument that contains the factor or from the Cholesky factorization of (the equilibrated) , in the same storage format as , returned by a previous call to**LA_POSVX**

If**FACT**'F' then**AF**is an*output*argument that contains the factor or from the Cholesky factorization of (the equilibrated) in the same storage format as .- FACT
*Optional*(*input)***CHARACTER(LEN=1)**.

Specifies whether the factored form of the matrix is supplied on entry, and, if not, whether should be equilibrated before it is factored.

Default value: 'N'.- EQUED
*Optional*(*input or output)***CHARACTER(LEN=1)**.

Specifies the form of equilibration that was done.

is an*input*argument if 'F', otherwise it is an*output*argument:

Default value: 'N'.- S
*Optional*(*input or output)***REAL**array, shape with .

The scaling factors for .**S**is an*input*argument if**FACT**= 'F' and**EQUED**= 'Y'.**S**is an*output*argument if**FACT**= 'E' and**EQUED**= 'Y'.- FERR
*Optional*(*output*)**REAL**array of shape , with , or**REAL**scalar.

The estimated forward error bound for each solution vector (the column of the solution matrix ). If is the true solution corresponding to , is an estimated upper bound for the magnitude of the largest element in ( divided by the magnitude of the largest element in . The estimate is as reliable as the estimate for , and is almost always a slight overestimate of the true error.- BERR
*Optional*(*output*)**REAL**array of shape , with , or**REAL**scalar.

The componentwise relative backward error of each solution vector (i.e., the smallest relative change in any element of or that makes an exact solution).- RCOND
*Optional*(*output)***REAL**

The estimate of the reciprocal condition number of (the equilibrated) . If is less than the machine precision, the matrix is singular to working precision. This condition is indicated by a return code of .- INFO
*Optional*(*output)***INTEGER**

If**INFO**is not present and an error occurs, then the program is terminated with an error message.