NA replaced by 0 when na.rm = TRUE in weighted.mean

[LDalby]

Title pretty much says it, but it looks like NA are being interpreted as 0 in weighted.mean when na.rm = TRUE
I get this on OSX with terra 1.5.21 and on Ubuntu with latest dev version of terra.

library(terra)
#> terra 1.5.21
x <- rast(nrows=10, ncols=10, xmin=0, xmax=10, vals = 1)
y <- rast(nrows=10, ncols=10, xmin=0, xmax=10, vals = 2)
z <- rast(nrows=10, ncols=10, xmin=0, xmax=10, vals = 3)
wt <- c(x,y,z)
z[1,1] <- NA
xt <- c(x,y,z)
weighted.mean(xt, wt, na.rm = TRUE) # min = 0.833
#> class       : SpatRaster 
#> dimensions  : 10, 10, 1  (nrow, ncol, nlyr)
#> resolution  : 1, 18  (x, y)
#> extent      : 0, 10, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 
#> source      : memory 
#> name        :       sum 
#> min value   : 0.8333333 
#> max value   :  2.333333
weighted.mean(c(1,2,0), 1:3)
#> [1] 0.8333333
# I exptected this:
weighted.mean(c(1,2,NA), 1:3, na.rm = TRUE)
#> [1] 1.666667

^{Created on 2022-03-17 by the reprex package (v2.0.1)}

[rhijmans]

Thanks. The sum of weights was not adjusted. So you with your example the value returned became (1*1+ 2*2) / (1+2+3) = 0.8333333

[LDalby]

Thank you for the fix and for the explanation!

[LDalby]

Looks like I was too fast. I'm still seeing the same behavior with the latest dev version.

library(terra)
#> terra 1.5.24
x <- rast(nrows=10, ncols=10, xmin=0, xmax=10, vals = 1)
y <- rast(nrows=10, ncols=10, xmin=0, xmax=10, vals = 2)
z <- rast(nrows=10, ncols=10, xmin=0, xmax=10, vals = 3)
wt <- c(x,y,z)
z[1,1] <- NA
xt <- c(x,y,z)

weighted.mean(xt, wt, na.rm = TRUE)
#> class       : SpatRaster 
#> dimensions  : 10, 10, 1  (nrow, ncol, nlyr)
#> resolution  : 1, 18  (x, y)
#> extent      : 0, 10, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 
#> source      : memory 
#> name        :       sum 
#> min value   : 0.8333333 
#> max value   :  2.333333
# The minimum is equivalent to:
weighted.mean(c(1,2,0), 1:3)
#> [1] 0.8333333

# But I expected it to be:
weighted.mean(x = c(1,2,NA), w = 1:3, na.rm = TRUE)
#> [1] 1.666667

^{Created on 2022-03-28 by the reprex package (v2.0.1)}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
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[rhijmans]

Very strange, but I think this is fixed now. It seems I only changed the version where w is a vector (but I recall that it worked for your example; must have done something wrong).