GNU Octave  4.0.0
A high-level interpreted language, primarily intended for numerical computations, mostly compatible with Matlab
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1 c Copyright (C) 2009-2015 VZLU Prague, a.s., Czech Republic
2 c
3 c Author: Jaroslav Hajek <>
4 c
5 c This file is part of Octave.
6 c
7 c Octave is free software; you can redistribute it and/or modify
8 c it under the terms of the GNU General Public License as published by
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12 c This program is distributed in the hope that it will be useful,
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15 c GNU General Public License for more details.
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17 c You should have received a copy of the GNU General Public License
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19 c <>.
20 c
21  subroutine zdotc3(m,n,k,a,b,c)
22 c purpose: a 3-dimensional dot product.
23 c c = sum (conj (a) .* b, 2), where a and b are 3d arrays.
24 c arguments:
25 c m,n,k (in) the dimensions of a and b
26 c a,b (in) double complex input arrays of size (m,k,n)
27 c c (out) double complex output array, size (m,n)
28  integer m,n,k,i,j,l
29  double complex a(m,k,n),b(m,k,n)
30  double complex c(m,n)
32  double complex zdotc
33  external zdotc
35 c quick return if possible.
36  if (m <= 0 .or. n <= 0) return
38  if (m == 1) then
39 c the column-major case.
40  do j = 1,n
41  c(1,j) = zdotc(k,a(1,1,j),1,b(1,1,j),1)
42  end do
43  else
44 c We prefer performance here, because that's what we generally
45 c do by default in reduction functions. Besides, the accuracy
46 c of xDOT is questionable. Hence, do a cache-aligned nested loop.
47  do j = 1,n
48  do i = 1,m
49  c(i,j) = 0d0
50  end do
51  do l = 1,k
52  do i = 1,m
53  c(i,j) = c(i,j) + conjg(a(i,l,j))*b(i,l,j)
54  end do
55  end do
56  end do
57  end if
59  end subroutine
subroutine zdotc3(m, n, k, a, b, c)
Definition: zdotc3.f:21