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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
# ACNVR -- Vector convolution with a real kernel. The output vector is equal
# to the sum of its initial value and the convolution of the input vector with
# the kernel. This routine assumes boundary extension on the input vector has
# been provided.
#
# Example: npix=10, kpix=5, 2 pixels out of bounds on either end.
# in[1] corresponds to x = -1
#
# -1 0 1 2 3 4 5 6 7 8 9 10 11 12 (x coord)
# 1 2 3 4 5
# 1 2 3 4 5
# ...
# 1 2 3 4 5
#
# See also acnv_, if the kernel is the same datatype as the data vectors.
procedure acnvrr (in, out, npix, kernel, knpix)
real in[npix+knpix-1] # input vector, including boundary pixels
real out[ARB] # output vector
int npix # length of output vector
real kernel[knpix] # convolution kernel, always type real
int knpix # size of convolution kernel
int i, j
real sum, k1, k2, k3, k4, k5
begin
switch (knpix) {
case 3:
k1 = kernel[1]
k2 = kernel[2]
k3 = kernel[3]
do i = 1, npix
out[i] = out[i] + k1 * in[i] + k2 * in[i+1] + k3 * in[i+2]
case 5:
k1 = kernel[1]
k2 = kernel[2]
k3 = kernel[3]
k4 = kernel[4]
k5 = kernel[5]
do i = 1, npix
out[i] = out[i] + k1 * in[i] + k2 * in[i+1] + k3 * in[i+2] +
k4 * in[i+3] + k5 * in[i+4]
default:
do i = 1, npix {
sum = out[i]
do j = 1, knpix
sum = sum + (kernel[j] * in[i+j-1])
out[i] = sum
}
}
end
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