[GRASS-dev] [GRASS GIS] #3067: r.mapcalc gives wrong result when neighborhood modifier takes a cell above first

[GRASS GIS]

#3067: r.mapcalc gives wrong result when neighborhood modifier takes a cell above
first
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 Reporter:  wenzeslaus                        |      Owner:  grass-dev@…
     Type:  defect                            |     Status:  new
 Priority:  blocker                           |  Milestone:  7.0.5
Component:  Raster                            |    Version:  svn-trunk
 Keywords:  r.mapcalc, neighborhood modifier  |        CPU:  Unspecified
 Platform:  Linux                             |
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 When I run G7:r.mapcalc with `x = p[1,0] + p[-1,0]` (r.mapcalc possibly
 first taking cell one row below), I get a correct result, but when I swap
 the parts if the expression to `x = p[-1,0] + p[1,0]` (r.mapcalc possibly
 first taking cell one row above), I get a wrong result. A reproducible
 example follows.

 {{{
 #!bash
 > r.in.ascii in=- out=p <<EOF
 north: 10
 south: 8
 east: 20
 west: 18
 rows: 3
 cols: 3
 1 0 1
 1 1 0
 1 1 0
 EOF
 > g.region rast=p
 > r.mapcalc "x1 = p[1,0] + p[-1,0]" && r.out.ascii x1
 north: 10
 south: 8
 east: 20
 west: 18
 rows: 3
 cols: 3
 * * *
 2 1 1
 * * *
 > r.mapcalc "x2 = p[-1,0] + p[1,0]" && r.out.ascii x2
 north: 10
 south: 8
 east: 20
 west: 18
 rows: 3
 cols: 3
 * * *
 2 2 0
 * * *
 }}}

 I get same result with or without r67851 (row cache fix for #2917).

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Ticket URL: <https://trac.osgeo.org/grass/ticket/3067>
GRASS GIS <https://grass.osgeo.org>