1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133
|
---
:name: zlarft
:md5sum: e49ec2f4472e3bae691c01b3a570c0e5
:category: :subroutine
:arguments:
- direct:
:type: char
:intent: input
- storev:
:type: char
:intent: input
- n:
:type: integer
:intent: input
- k:
:type: integer
:intent: input
- v:
:type: doublecomplex
:intent: input/output
:dims:
- ldv
- "lsame_(&storev,\"C\") ? k : lsame_(&storev,\"R\") ? n : 0"
- ldv:
:type: integer
:intent: input
- tau:
:type: doublecomplex
:intent: input
:dims:
- k
- t:
:type: doublecomplex
:intent: output
:dims:
- ldt
- k
- ldt:
:type: integer
:intent: input
:substitutions:
ldt: k
:fortran_help: " SUBROUTINE ZLARFT( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )\n\n\
* Purpose\n\
* =======\n\
*\n\
* ZLARFT forms the triangular factor T of a complex block reflector H\n\
* of order n, which is defined as a product of k elementary reflectors.\n\
*\n\
* If DIRECT = 'F', H = H(1) H(2) . . . H(k) and T is upper triangular;\n\
*\n\
* If DIRECT = 'B', H = H(k) . . . H(2) H(1) and T is lower triangular.\n\
*\n\
* If STOREV = 'C', the vector which defines the elementary reflector\n\
* H(i) is stored in the i-th column of the array V, and\n\
*\n\
* H = I - V * T * V'\n\
*\n\
* If STOREV = 'R', the vector which defines the elementary reflector\n\
* H(i) is stored in the i-th row of the array V, and\n\
*\n\
* H = I - V' * T * V\n\
*\n\n\
* Arguments\n\
* =========\n\
*\n\
* DIRECT (input) CHARACTER*1\n\
* Specifies the order in which the elementary reflectors are\n\
* multiplied to form the block reflector:\n\
* = 'F': H = H(1) H(2) . . . H(k) (Forward)\n\
* = 'B': H = H(k) . . . H(2) H(1) (Backward)\n\
*\n\
* STOREV (input) CHARACTER*1\n\
* Specifies how the vectors which define the elementary\n\
* reflectors are stored (see also Further Details):\n\
* = 'C': columnwise\n\
* = 'R': rowwise\n\
*\n\
* N (input) INTEGER\n\
* The order of the block reflector H. N >= 0.\n\
*\n\
* K (input) INTEGER\n\
* The order of the triangular factor T (= the number of\n\
* elementary reflectors). K >= 1.\n\
*\n\
* V (input/output) COMPLEX*16 array, dimension\n\
* (LDV,K) if STOREV = 'C'\n\
* (LDV,N) if STOREV = 'R'\n\
* The matrix V. See further details.\n\
*\n\
* LDV (input) INTEGER\n\
* The leading dimension of the array V.\n\
* If STOREV = 'C', LDV >= max(1,N); if STOREV = 'R', LDV >= K.\n\
*\n\
* TAU (input) COMPLEX*16 array, dimension (K)\n\
* TAU(i) must contain the scalar factor of the elementary\n\
* reflector H(i).\n\
*\n\
* T (output) COMPLEX*16 array, dimension (LDT,K)\n\
* The k by k triangular factor T of the block reflector.\n\
* If DIRECT = 'F', T is upper triangular; if DIRECT = 'B', T is\n\
* lower triangular. The rest of the array is not used.\n\
*\n\
* LDT (input) INTEGER\n\
* The leading dimension of the array T. LDT >= K.\n\
*\n\n\
* Further Details\n\
* ===============\n\
*\n\
* The shape of the matrix V and the storage of the vectors which define\n\
* the H(i) is best illustrated by the following example with n = 5 and\n\
* k = 3. The elements equal to 1 are not stored; the corresponding\n\
* array elements are modified but restored on exit. The rest of the\n\
* array is not used.\n\
*\n\
* DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':\n\
*\n\
* V = ( 1 ) V = ( 1 v1 v1 v1 v1 )\n\
* ( v1 1 ) ( 1 v2 v2 v2 )\n\
* ( v1 v2 1 ) ( 1 v3 v3 )\n\
* ( v1 v2 v3 )\n\
* ( v1 v2 v3 )\n\
*\n\
* DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':\n\
*\n\
* V = ( v1 v2 v3 ) V = ( v1 v1 1 )\n\
* ( v1 v2 v3 ) ( v2 v2 v2 1 )\n\
* ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )\n\
* ( 1 v3 )\n\
* ( 1 )\n\
*\n\
* =====================================================================\n\
*\n"
|