1 // =============================================================================
2 // === spqr_shift ==============================================================
3 // =============================================================================
4
5 // Insert a zero as the first entry in a vector, shifting all the other entries
6 // down by one position. Does nothing if X is NULL.
7
8 #include "spqr.hpp"
9
spqr_shift(Long n,Long * X)10 void spqr_shift
11 (
12 // input, not modified
13 Long n,
14
15 // input/output
16 Long *X // size n+1
17 )
18 {
19 Long k ;
20 if (X != NULL)
21 {
22 for (k = n ; k >= 1 ; k--)
23 {
24 X [k] = X [k-1] ;
25 }
26 X [0] = 0 ;
27 }
28 }
29