Fdlap.m - Revision history

Kuprov: Update function See also links and function index membership

2026-06-06T18:36:36Z

Update function See also links and function index membership

Kuprov: Rename Arguments section heading to Parameters

2026-06-05T17:48:51Z

Rename Arguments section heading to Parameters

Kuprov: Spot-edit Spinach function page first-line NOTOC and template fields

2026-06-05T17:27:51Z

Spot-edit Spinach function page first-line NOTOC and template fields

Kuprov: Normalise sequential blank lines

2026-04-25T11:25:06Z

Normalise sequential blank lines

Kuprov: Restore pre-bulk-edit wiki content

2026-04-05T14:48:35Z

Restore pre-bulk-edit wiki content

Kuprov: Sync syntax/arguments/outputs with current Spinach source

2026-04-05T14:02:58Z

Sync syntax/arguments/outputs with current Spinach source

Admin: /* See also */

2018-08-16T14:19:16Z

‎See also

Admin at 14:19, 16 August 2018

2018-08-16T14:19:03Z

Admin at 14:18, 16 August 2018

2018-08-16T14:18:52Z

Admin: Created page with "Returns a finite-difference representation of the Laplacian for a 3D array with a user-specified finite difference stencil size. The re- sulting operator is a sparse matrix de..."

2015-11-02T16:23:10Z

Created page with "Returns a finite-difference representation of the Laplacian for a 3D array with a user-specified finite difference stencil size. The re- sulting operator is a sparse matrix de..."

New page

Returns a finite-difference representation of the Laplacian for a 3D array with a user-specified finite difference stencil size. The re-
sulting operator is a sparse matrix designed to act on the vectorization of the 3D array. The dimensions of the 3D array are assumed to be ordered as [X Y Z]. Syntax:

L=fdlap(npoints,extents,nstenc)

The following parameters are needed:

npoints - a three-element vector specifying the number of
discretization points in each dimension of the
3D cube of data that the operator will be acting
on, ordered as [X Y Z].

extents - a three-element vector specifying axis extents,
ordered as [X Y Z].

nstenc - number of finite-difference stencil points for
the finite-difference approximations.

The resulting operator is a sparse matrix designed to act on the vectorization of rho. The dimensions of rho are assumed to be ordered as [X Y Z].

Note: Dirichlet boundary conditions - the resulting Laplacian should only be used for the inverse Laplacian operation.

@@ Line 29: / Line 29: @@
 ==See also==
-[[fdvec.m]], [[fdmat.m]], [[fdhess.m]], [[fdkup.m]], [[fdweights.m]], [[fftdiff.m]], [[fourdif.m]], [[fourlap.m]]
+[[fdvec.m]], [[fdmat.m]], [[fdhess.m]], [[fdkup.m]], [[fdweights.m]], [[fftdiff.m]], [[fourdif.m]], [[fourlap.m]], [[cgsppm2ang.m]], [[corrfun.m]], [[fpl2phan.m]], [[fpl2rho.m]], [[hydrodynamics.m]], [[interpmat.m]], [[oscillator.m]], [[overwound.m]], [[phan2fpl.m]], [[points2mult.m]], [[qform2sph.m]], [[qxspen_kernel.m]], [[spden.m]], [[Hyperfine_shift_module]], [[Kernel_utilities]]
 ''Version 2.2, authors: [[Ilya Kuprov]]''

@@ Line 6: / Line 6: @@
       L=fdlap(npoints,extents,nstenc)
-==Arguments==
+==Parameters==
       dims    -  a one-element, two-element, or three-element

← Older revision		Revision as of 17:27, 5 June 2026
Line 1:		Line 1:
−	{{DISPLAYTITLE:fdlap.m}}	+	{{DISPLAYTITLE:fdlap.m}} __NOTOC__
	Returns a finite-difference representation of the Laplacian for an array with a user-specified finite difference stencil size. The resulting operator is a sparse matrix designed to act on the vectorisation of the array. The dimensions of the array are assumed to be ordered as [X Y Z].		Returns a finite-difference representation of the Laplacian for an array with a user-specified finite difference stencil size. The resulting operator is a sparse matrix designed to act on the vectorisation of the array. The dimensions of the array are assumed to be ordered as [X Y Z].

@@ Line 30: / Line 30: @@
 ==See also==
 [[fdvec.m]], [[fdmat.m]], [[fdhess.m]], [[fdkup.m]], [[fdweights.m]], [[fftdiff.m]], [[fourdif.m]], [[fourlap.m]]
 ''Version 2.2, authors: [[Ilya Kuprov]]''

@@ Line 1: / Line 1: @@
-{{DISPLAYTITLE:fdlap.m}} __NOTOC__
+{{DISPLAYTITLE:fdlap.m}}
 Returns a finite-difference representation of the Laplacian for an array with a user-specified finite difference stencil size. The resulting operator is a sparse matrix designed to act on the vectorisation of the array. The dimensions of the array are assumed to be ordered as [X Y Z].
 ==Syntax==
-L=fdlap(dims,extents,nstenc)
+     L=fdlap(npoints,extents,nstenc)
 ==Arguments==
-dims    -  a one-element, two-element, or three-element
+     dims    -  a one-element, two-element, or three-element
                  vector specifying the number of discretisation
                  points in each dimension of the 1D, 2D, or 3D
@@ Line 25: / Line 24: @@
 ==Outputs==
-L       -  a sparse matrix designed to act on the vectori-
+     L       -  a sparse matrix designed to act on the vectori-
                  zation of the 3D array. The dimensions of that
                  array are assumed to be ordered as [X Y Z].
 ==See also==
 [[fdvec.m]], [[fdmat.m]], [[fdhess.m]], [[fdkup.m]], [[fdweights.m]], [[fftdiff.m]], [[fourdif.m]], [[fourlap.m]]
 ''Version 2.2, authors: [[Ilya Kuprov]]''

← Older revision		Revision as of 14:19, 16 August 2018
Line 32:		Line 32:


−	''Version 2.2, authors: [[Ilya Kuprov]''	+	''Version 2.2, authors: [[Ilya Kuprov]]''

@@ Line 1: / Line 1: @@
-Returns a finite-difference representation of the Laplacian for a 3D array with a user-specified finite difference stencil size. The re-
+{{DISPLAYTITLE:function.m}}
-sulting operator is a sparse matrix designed to act on the vectorization of the 3D array. The dimensions of the 3D array are assumed to be ordered as [X Y Z]. Syntax:
+Returns a finite-difference representation of the Laplacian for an array with a user-specified finite difference stencil size. The resulting operator is a sparse matrix designed to act on the vectorisation of the array. The dimensions of the array are assumed to be ordered as [X Y Z].
-                    L=fdlap(npoints,extents,nstenc)
+==Syntax==
-The following parameters are needed:
+     L=fdlap(npoints,extents,nstenc)
-      npoints -  a three-element vector specifying the number of
+      nstenc  -  number of finite-difference stencil points for
-                 discretization points in each dimension of the
+                 the finite-difference approximation; periodic
-D cube of data that the operator will be acting
+                 boundary conditions are used
-                on, ordered as [X Y Z].
-      extents -  a three-element vector specifying axis extents,
+      L       -  a sparse matrix designed to act on the vectori-
-                 ordered as [X Y Z].
+                 zation of the 3D array. The dimensions of that
-     nstenc  -  number of finite-difference stencil points for
+==See also==
-                the finite-difference approximations.
+[[fdvec.m]], [[fdmat.m]], [[fdhess.m]], [[fdkup.m]], [[fdweights.m]], [[fftdiff.m]], [[fourdif.m]], [[fourlap.m]]
-Note: Dirichlet boundary conditions - the resulting Laplacian should only be used for the inverse Laplacian operation.
+''Version 2.2, authors: [[Ilya Kuprov]''