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SUBROUTINE DCOSQB (N,X,WSAVE)
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IMPLICIT DOUBLE PRECISION (A-H,O-Z)
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DIMENSION X(*) ,WSAVE(*)
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DATA TSQRT2 /2.82842712474619009760D0/
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102 X1 = 4.0D0*(X(1)+X(2))
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X(2) = TSQRT2*(X(1)-X(2))
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103 CALL DCOSQB1 (N,X,WSAVE,WSAVE(N+1))
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SUBROUTINE DCOSQB1 (N,X,W,XH)
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IMPLICIT DOUBLE PRECISION (A-H,O-Z)
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DIMENSION X(1) ,W(1) ,XH(1)
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IF (MODN .EQ. 0) X(N) = X(N)+X(N)
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XH(K) = W(K-1)*X(KC)+W(KC-1)*X(K)
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XH(KC) = W(K-1)*X(K)-W(KC-1)*X(KC)
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IF (MODN .EQ. 0) X(NS2+1) = W(NS2)*(X(NS2+1)+X(NS2+1))