survey#

Functions

`atgeometry()`	Computes the 2-D position of all elements (no vertical bend)
`atgeometry3()`	Computes the 3-D position of all elements

atgeometry(ring, refpts)#: Computes the 2-D position of all elements (no vertical bend)

posdata=atgeometry(ring,refpts)

RING: AT structure

REFPTS: observation points (array of indexes or logical mask)

The allowed range is 1 to length(RING)+1

Defaults to 1:length(RING)+1

POSDATA:Structure array, same length as REFPTS, with 5 fields:

x, y, angle, long, trans

[posdata,radius]=atgeometry(ring,refpts)

Outputs the machine radius at the beginning of the lattice.

Note: this is different from the radius usually defined as

circumference/2/pi

posdata=atgeometry(…,’centered’)

The offset is set so that the origin is at the centre of the ring

posdata=atgeometry(ring,refpts,offset)

Start at x=offset(1), y=offset(2). Ignored if ‘centered’ is set.

A scalar offset value is equivalent to [0 OFFSET].

posdata=atgeometry(…,’hangle’,h_angle)

Set the initial trajectory angle

See also atgeometry3()

atgeometry3(ring, refpts)#: Computes the 3-D position of all elements

posdata=atgeometry3(ring,refpts)

RING: AT structure

REFPTS: observation points (array of indexes or logical mask)

The allowed range is 1 to length(RING)+1

Defaults to 1:length(RING)+1

POSDATA:Structure array, same length as REFPTS, with 3 fields:

x, y, z

posdata=atgeometry3(ring,refpts,offset)

Start at x=offset(1), y=offset(2), z=offset(3)

a scalar offset value is equivalent to [0 OFFSET 0]

posdata=atgeometry3(…,’hangle’,h_angle)

Set the initial horizontal trajectory angle

posdata=atgeometry3(…,’vangle’,h_angle)

Set the initial vertical trajectory angle

See also atgeometry()