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cdotc.f 2.3 kB

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  1. *> \brief \b CDOTC
  2. *
  3. * =========== DOCUMENTATION ===========
  4. *
  5. * Online html documentation available at
  6. * http://www.netlib.org/lapack/explore-html/
  7. *
  8. * Definition:
  9. * ===========
  10. *
  11. * COMPLEX FUNCTION CDOTC(N,CX,INCX,CY,INCY)
  12. *
  13. * .. Scalar Arguments ..
  14. * INTEGER INCX,INCY,N
  15. * ..
  16. * .. Array Arguments ..
  17. * COMPLEX CX(*),CY(*)
  18. * ..
  19. *
  20. *
  21. *> \par Purpose:
  22. * =============
  23. *>
  24. *> \verbatim
  25. *>
  26. *> CDOTC forms the dot product of two complex vectors
  27. *> CDOTC = X^H * Y
  28. *>
  29. *> \endverbatim
  30. *
  31. * Authors:
  32. * ========
  33. *
  34. *> \author Univ. of Tennessee
  35. *> \author Univ. of California Berkeley
  36. *> \author Univ. of Colorado Denver
  37. *> \author NAG Ltd.
  38. *
  39. *> \date December 2016
  40. *
  41. *> \ingroup complex_blas_level1
  42. *
  43. *> \par Further Details:
  44. * =====================
  45. *>
  46. *> \verbatim
  47. *>
  48. *> jack dongarra, linpack, 3/11/78.
  49. *> modified 12/3/93, array(1) declarations changed to array(*)
  50. *> \endverbatim
  51. *>
  52. * =====================================================================
  53. COMPLEX FUNCTION CDOTC(N,CX,INCX,CY,INCY)
  54. *
  55. * -- Reference BLAS level1 routine (version 3.7.0) --
  56. * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
  57. * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
  58. * December 2016
  59. *
  60. * .. Scalar Arguments ..
  61. INTEGER INCX,INCY,N
  62. * ..
  63. * .. Array Arguments ..
  64. COMPLEX CX(*),CY(*)
  65. * ..
  66. *
  67. * =====================================================================
  68. *
  69. * .. Local Scalars ..
  70. COMPLEX CTEMP
  71. INTEGER I,IX,IY
  72. * ..
  73. * .. Intrinsic Functions ..
  74. INTRINSIC CONJG
  75. * ..
  76. CTEMP = (0.0,0.0)
  77. CDOTC = (0.0,0.0)
  78. IF (N.LE.0) RETURN
  79. IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
  80. *
  81. * code for both increments equal to 1
  82. *
  83. DO I = 1,N
  84. CTEMP = CTEMP + CONJG(CX(I))*CY(I)
  85. END DO
  86. ELSE
  87. *
  88. * code for unequal increments or equal increments
  89. * not equal to 1
  90. *
  91. IX = 1
  92. IY = 1
  93. IF (INCX.LT.0) IX = (-N+1)*INCX + 1
  94. IF (INCY.LT.0) IY = (-N+1)*INCY + 1
  95. DO I = 1,N
  96. CTEMP = CTEMP + CONJG(CX(IX))*CY(IY)
  97. IX = IX + INCX
  98. IY = IY + INCY
  99. END DO
  100. END IF
  101. CDOTC = CTEMP
  102. RETURN
  103. END