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

Required Arguments

A — Real (NUC + 1 + NLC) by N array containing the band matrix in band storage mode.   (Input)

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

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

B — Real N by N array containing the matrix.   (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 CRBRG (A, NLC, NUC, B [,…])

Specific:         The specific interface names are S_CRBRG and D_CRBRG.

FORTRAN 77 Interface

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

Double:          The double precision name is DCRBRG.

Description

The routine CRBRG converts the real band matrix A of order N in band storage mode into the real
N ´ N general matrix B with mu = NUC upper codiagonals and ml = NLC lower codiagonals. The first mu rows of A are copied to the upper codiagonals of B, the next row of A is copied to the diagonal of B, and the last ml rows of A are copied to the lower codiagonals of B.

Example

A real band matrix of order 3 in band storage mode with one upper codiagonal and one lower codiagonal is copied to a 3 ´ 3 real general matrix.

 

      USE CRBRG_INT

      USE WRRRN_INT

 

      IMPLICIT   NONE

!                                 Declare variables

      INTEGER    LDA, LDB, N, NLC, NUC

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

!

      REAL       A(LDA,N), B(LDB,N)

!                                 Set values for  A (in band mode)

!                                 A = (  0.0     1.0    1.0)

!                                     (  4.0     3.0    2.0)

!                                     (  2.0     2.0    0.0)

!

      DATA A/0.0, 4.0, 2.0, 1.0, 3.0, 2.0, 1.0, 2.0, 0.0/

!                                 Convert band matrix A to matrix B

      CALL CRBRG (A, NLC, NUC, B)

!                                 Print results

      CALL WRRRN ('B', B)

      END

Output

 

             B
        1       2       3
1   4.000   1.000   0.000
2   2.000   3.000   1.000
3   0.000   2.000   2.000

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