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Diffstat (limited to 'sys/vops/ak/abavl.x')
| -rw-r--r-- | sys/vops/ak/abavl.x | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/sys/vops/ak/abavl.x b/sys/vops/ak/abavl.x new file mode 100644 index 00000000..29332022 --- /dev/null +++ b/sys/vops/ak/abavl.x @@ -0,0 +1,36 @@ +# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc. + +# ABAV -- Vector block average. Each pixel in the output vector is the +# average of the input vector over a block of pixels. The input vector must +# be at least (nblocks * npix_per_block) pixels in length. + +procedure abavl (a, b, nblocks, npix_per_block) + +long a[ARB] # input vector +long b[nblocks] # output vector +int nblocks # number of blocks (pixels in output vector) +int npix_per_block # number of input pixels per block + +real sum, width + +int i, j +int block_offset, next_block, block_length + +begin + block_offset = 1 + block_length = npix_per_block + width = block_length + + if (block_length <= 1) + call amovl (a[block_offset], b, nblocks) + else { + do j = 1, nblocks { + next_block = block_offset + block_length + sum = 0 + do i = block_offset, next_block - 1 + sum = sum + a[i] + b[j] = sum / width + block_offset = next_block + } + } +end |