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PROGRAM TEST
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IMPLICIT NONE
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C
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INTEGER LDA, N, NDIAG
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PARAMETER (N = 4)
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PARAMETER (NDIAG = 1)
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PARAMETER (LDA = NDIAG + 1)
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C
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DOUBLE PRECISION A(LDA,N), DET(2)
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INTEGER ICOL, INFO, IROW, NDIAG
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EXTERNAL DPBDI, DPBFA
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C
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C Initialize the array A to store in banded storage mode
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C the matrix A shown below.
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C
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C 2 -1 0 0
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C A = -1 2 -1 0
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C 0 -1 2 -1
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C 0 0 -1 2
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C
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DATA A / 8D8, 2.0D0, -1.0D0, 2.0D0, -1.0D0, 2.0D0, -1.0D0,
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$ 2.0D0 /
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C
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PRINT 1000
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PRINT 1010, A(2,1), A(1,2)
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PRINT 1010, A(3,1), A(2,2), A(1,3)
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PRINT 1020, A(3,2), A(2,3), A(1,4)
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PRINT 1030, A(3,3), A(2,4)
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PRINT 1040
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PRINT 1010, ((A(IROW,ICOL), ICOL = 1, N), IROW = 1, LDA)
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CALL DPBFA (A, LDA, N, NDIAG, INFO)
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IF (INFO .EQ. 0) THEN
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CALL DPBDI (A, LDA, N, NDIAG, DET)
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PRINT 1050, DET(1) * (10.0D0 ** DET(2))
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ELSE
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PRINT 1060
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END IF
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C
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1000 FORMAT (1X, 'A in full form:')
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1010 FORMAT (4(3X, F5.1))
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1020 FORMAT (8X, 3(3X, F5.1))
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1030 FORMAT (16X, 3(3X, F5.1))
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1040 FORMAT (/1X, 'A in banded form: (* in unused entries)')
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1050 FORMAT (/1X, 'The determinant of A is ', F5.1)
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1060 FORMAT (/1X, 'A is not positive definite.')
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C
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END
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