Merge pull request #32 from campa-consortium/dcs16/03

Coordinate systems standard

myst.yml

@@ -18,7 +18,9 @@ project:
       children:
         - file: 'source/standard/introduction.md'
         - file: 'source/standard/element_parameter.md'
+        - file: 'source/standard/coordinates.md'
 site:
   template: book-theme
   #domains:
   #  - <username>-<project>.curve.space
+

source/conf.py

@@ -14,7 +14,8 @@
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
 
 extensions = ['myst_parser', 'sphinx_design']
-myst_enable_extensions = ["colon_fence"]
+myst_enable_extensions = ["colon_fence", "amsmath"]
+numfig = True
 
 templates_path = ['_templates']
 exclude_patterns = []

source/index.md

@@ -18,4 +18,5 @@ front_matter/how_to_write_docs.md
 
 standard/introduction.md
 standard/element_parameter.md
+standard/coordinates.md
 ```

source/standard/introduction.md

@@ -58,11 +58,21 @@ By convention, element names in ALS will be upper camel case.
 
 ## Lattice Branches
 
-A lattice **Branch** is essentially an ordered array of lattice elements that gives the physical
-sequence to be tracked through.
-In the simplest case, a program can track through the elements one element at a time.
+A lattice **branch** holds a collection of lattice elements. 
+There are two types of branches. One type, called a "tracking branch", holds
+an ordered array of lattice elements that gives a
+sequence of elements to be tracked through. A tracking branch can represent something like a
+storage ring, transfer line or Linac.
+In the simplist case, a program can track through the elements one element at a time.
 However, lattice elements may overlap which will naturally complicate tracking.
 
+The other type of branch, called a "lord" branch, is used to hold lattice elements that help describe:
+- Support elements (Girders)
+- Overlapping elements (Superposition)
+- Situations where an element is transversed multiple times as in an ERL or in opposite directions
+as in a colliding beam machine (Multipass)
+Lord branches will be explained in detail in later sections.
+
 ## Lattices
 
 A **lattice is the root structure holding the information about a
@@ -77,5 +87,5 @@ This is used to simulate forking beam lines such as a connections to a transfer
 X-ray beam line. The **branch** from which other **branches** fork but is not forked to by any
 other branch is called a **root** branch.
 
-A lattice may contain multiple **root branches. For example, a pair of intersecting storage
+A lattice may contain multiple **root** branches. For example, a pair of intersecting storage
 rings will generally have two root branches, one for each ring.