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-rw-r--r--SRC/slarfb.f27
1 files changed, 26 insertions, 1 deletions
diff --git a/SRC/slarfb.f b/SRC/slarfb.f
index 234ba229..a4f23c17 100644
--- a/SRC/slarfb.f
+++ b/SRC/slarfb.f
@@ -59,7 +59,7 @@
* (LDV,K) if STOREV = 'C'
* (LDV,M) if STOREV = 'R' and SIDE = 'L'
* (LDV,N) if STOREV = 'R' and SIDE = 'R'
-* The matrix V. See further details.
+* The matrix V. See Further Details.
*
* LDV (input) INTEGER
* The leading dimension of the array V.
@@ -88,6 +88,31 @@
* If SIDE = 'L', LDWORK >= max(1,N);
* if SIDE = 'R', LDWORK >= max(1,M).
*
+* Further Details
+* ===============
+*
+* The shape of the matrix V and the storage of the vectors which define
+* the H(i) is best illustrated by the following example with n = 5 and
+* k = 3. The elements equal to 1 are not stored; the corresponding
+* array elements are modified but restored on exit. The rest of the
+* array is not used.
+*
+* DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
+*
+* V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
+* ( v1 1 ) ( 1 v2 v2 v2 )
+* ( v1 v2 1 ) ( 1 v3 v3 )
+* ( v1 v2 v3 )
+* ( v1 v2 v3 )
+*
+* DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
+*
+* V = ( v1 v2 v3 ) V = ( v1 v1 1 )
+* ( v1 v2 v3 ) ( v2 v2 v2 1 )
+* ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
+* ( 1 v3 )
+* ( 1 )
+*
* =====================================================================
*
* .. Parameters ..