interpolation - using interp1 in R for matrix -

i trying use interp1 function in r linearly interpolating matrix without using loop. far have tried:

bthd <- c(0,2,3,4,5) # original depth vector btha <- c(4000,3500,3200,3000,2800) # original array of area  temp <- c(4.5,4.2,4.2,4,5,5,4.5,4.2,4.2,4) temp <- matrix(temp,2) # matrix temperature measurements  # -- interpolating bathymetry data  -- depthtemp <- c(0.5,1,2,3,4) layerz <- seq(depthtemp[1],depthtemp[5],0.1)  library(signal) layera <- interp1(bthd,btha,layerz);  # -- interpolate= matrix -- layert <- list() (i in 1:2){   t <- temp[i,]   layert[[i]] <- interp1(depthtemp,t,layerz)   } layert <- do.call(rbind,layert) 

so, here have used interp1 on each row of matrix in loop. know how without using loop. can in matlab transposing matrix follows:

layert = interp1(depthtemp,temp',layerz)'; % matlab code 

but when attempt in r

layert <- interp1(depthtemp,t(temp),layerz) 

it not return matrix of interpolated results, numeric array. how can ensure r returns matrix of interpolated values?

• there nothing wrong approach; avoid intermediate t <-

• if want feel r-ish, try

apply(temp,1,function(t) interp1(depthtemp,t,layerz))

you may have add t(ranspose) in front of if need way.

since 3d-field, per-row interpolation might not optimal. favorite interp.loess in package tgp, regular spacings other options might available. method not work mini-example (which fine question), required larger grid.