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PROGRAM TEST
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IMPLICIT NONE
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C
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DOUBLE PRECISION ZERO
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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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PARAMETER (ZERO = 0.0D0)
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C
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DOUBLE PRECISION A(LDA,N), B(N)
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INTEGER I, J
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C
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EXTERNAL DTBSV
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C
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C Initialize the array A to store in triangular banded form
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C the triangular banded matrix A shown below. Initialize
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C the array B to store the vector b shown below.
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C
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C 1 8
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C A = 2 3 b = 43
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C 4 5 86
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C 6 7 137
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C
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DATA A / 1.0D0, 2.0D0, 3.0D0, 4.0D0, 5.0D0, 6.0D0, 7.0D0,
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$ 8D8 /
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DATA B / 8.0D0, 4.3D1, 8.6D1, 1.37D2 /
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C
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PRINT 1000
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PRINT 1010, A(1,1)
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PRINT 1010, A(2,1), A(1,2)
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PRINT 1020, A(2,2), A(1,3)
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PRINT 1030, A(2,3), A(1,4)
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PRINT 1040
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DO 10, I = 1, LDA
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PRINT 1010, (A(I,J), J = 1, N)
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10 CONTINUE
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PRINT 1050
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PRINT 1060, B
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CALL DTBSV ('LOWER TRIANGULAR A', 'NOT TRANSPOSED A',
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$ 'NOT UNIT DIAGONAL A', N, 1, A, LDA, B, 1)
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PRINT 1070
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PRINT 1060, B
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C
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1000 FORMAT (1X, 'A in full form:')
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1010 FORMAT (1X, 4(2X, F5.1))
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1020 FORMAT (8X, 2(2X, F5.1))
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1030 FORMAT (15X, 2(2X, F5.1))
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1040 FORMAT (/1X, 'A in triangular banded form: ',
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$ '(* in unused elements)')
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1050 FORMAT (/1X, 'b:')
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1060 FORMAT (3X, F5.1)
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1070 FORMAT (/1X, 'A**(-1) * b:')
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C
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END
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