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DiskMatrix

DiskMatrix[r]
gives a matrix whose elements are 1 in a disk-shaped region of radius r, and are otherwise 0.
DiskMatrix[r, w]
gives a w×w matrix containing a disk of 1s with radius r.
DiskMatrix[{r1, r2, ...}, ...]
yields an array whose elements are 1 in an ellipsoidal region with semi-axis ri in the i^(th) index direction.
  • The disk of 1s is always at the center of the region.
  • In DiskMatrix[r] or DiskMatrix[{r1, ...}] the matrix or array is sized so as to just include all nonzero elements.
  • The disk-like region is taken to be the best discrete approximation to a circular disk possible given the size of the matrix.
  • DiskMatrix[All, w] gives a w×w matrix containing a disk that is as large as possible.
  • DiskMatrix[..., {w1, w2, ...}] gives a w1×w2×... array.
  • DiskMatrix[{r1, ..., rn}, w] gives a w×...×w array.
  • DiskMatrix[All, {w1, ..., wn}] gives a w1×...×wn array containing an ellipsoid that is as large as possible.
  • The radius r need not be an integer; in general elements are 1 if their distance from the center is not more than |r+1/2|.
  • For integer r, DiskMatrix[r] yields a (2r+1)×(2r+1) matrix.
This computes and plots a square disk-shaped matrix of radius 7:
This computes and plots a square disk-shaped matrix of radius 7:
In[1]:=
Click for copyable input
Out[1]=
Create a rectangular ellipse-shaped matrix:
Put a disk inside a bigger matrix:
Extend the disk to the boundaries of the matrix:
Automatically choose an odd width to just fit the disk:
Extend the disk to the given width, and automatically choose the height:
New in 7