CCGCB

Converts a complex general matrix to a matrix in complex band storage mode.

Required Arguments

A — Complex N by N array containing the matrix. (Input)

NLC — Number of lower codiagonals in B. (Input)

NUC — Number of upper codiagonals in B. (Input)

B — Complex (NUC + 1 + NLC) by N array containing the band matrix in band storage mode. (Output)

Optional Arguments

N — Order of the matrices A and B. (Input)
Default: N = SIZE (A,2).

LDA — Leading dimension of A exactly as specified in the dimension statement of the calling program. (Input)
Default: LDA = SIZE (A,1).

LDB — Leading dimension of B exactly as specified in the dimension statement of the calling program. (Input)
Default: LDB = SIZE (B,1).

FORTRAN 90 Interface

Generic: CALL CCGCB (A, NLC, NUC, B [, …])

Specific: The specific interface names are S_CCGCB and D_CCGCB.

FORTRAN 77 Interface

Single: CALL CCGCB (N, A, LDA, NLC, NUC, B, LDB)

Double: The double precision name is DCCGCB.

Description

The routine CCGCB converts the complex general matrix A of order N with mu = NUC upper codiagonals and ml = NLC lower codiagonals into the complex band matrix B of order N in band storage mode. The first mu rows of B then contain the upper codiagonals of A, the next row contains the main diagonal of A, and the last ml rows of B contain the lower codiagonals of A.

Example

A complex general matrix of order 4 with one upper codiagonal and three lower codiagonals is copied to a complex band matrix of order 4 in band storage mode.

 

USE CCGCB_INT

USE WRCRN_INT

 

IMPLICIT NONE

! Declare variables

INTEGER LDA, LDB, N, NLC, NUC

PARAMETER (LDA=4, LDB=5, N=4, NLC=3, NUC=1)

!

COMPLEX A(LDA,N), B(LDB,N)

! Set values for A

! A = ( 1.0+0.0i 2.0+1.0i 0.0+0.0i 0.0+0.0i )

! ( -2.0+1.0i 1.0+0.0i 3.0+2.0i 0.0+0.0i )

! ( 0.0+0.0i -3.0+2.0i 1.0+0.0i 4.0+3.0i )

! ( -7.0+1.0i 0.0+0.0i -4.0+3.0i 1.0+0.0i )

!

DATA A/(1.0,0.0), (-2.0,1.0), (0.0,0.0), (-7.0,1.0), (2.0,1.0), &

(1.0,0.0), (-3.0,2.0), (0.0,0.0), (0.0,0.0), (3.0,2.0), &

(1.0,0.0), (-4.0,3.0), (0.0,0.0), (0.0,0.0), (4.0,3.0), &

(1.0,0.0)/

! Convert A to band matrix B

CALL CCGCB (A, NLC, NUC, B)

! Print results

CALL WRCRN ('B', B)

END

Output

 

B

1 2 3 4

1 ( 0.000, 0.000) ( 2.000, 1.000) ( 3.000, 2.000) ( 4.000, 3.000)

2 ( 1.000, 0.000) ( 1.000, 0.000) ( 1.000, 0.000) ( 1.000, 0.000)

3 (-2.000, 1.000) (-3.000, 2.000) (-4.000, 3.000) ( 0.000, 0.000)

4 ( 0.000, 0.000) ( 0.000, 0.000) ( 0.000, 0.000) ( 0.000, 0.000)

5 (-7.000, 1.000) ( 0.000, 0.000) ( 0.000, 0.000) ( 0.000, 0.000)