Index

Core dictionary version 3.0.14

_function.SeitzFromJones

Definition:

   
     The function
               s  =  SeitzFromJones( j )
 
     returns a 4x4 Seitz matrix from the Jones faithful representation of
     the equivalent position which is a character string e.g. 1/2+x,-x,z.

Type: Real

Values appear in Matrix context.

Dimension: [4,4]

Evaluation method:

     Function SeitzFromJones( j :[Single, Text])  { # Jones symmetry notation
 
      joneschrs = "123456xyz/,+- "
      s         = Matrix([[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,1]])
      axis      = 0
      sign      = 1
      inum      = 0
 
      do i=0,Len(j)-1    {
          c = j[i]
          If (c not in joneschrs) dummy = print('illegal char in symmetry xyz')
 
          If      (c == ' ') Next
          If      (c == ',') {
                             axis     += 1
                             inum      = 0
                             sign      = 1
          }
          Else If (c == '+') sign      = +1
          Else If (c == '-') sign      = -1
          Else If (c == 'x') s[axis,0] = sign
          Else If (c == 'y') s[axis,1] = sign
          Else If (c == 'z') s[axis,2] = sign
          Else   {
               If (inum == 0)   m  = AtoI(c)
               If (inum == 1 and c != '/') dummy = print('illegal num in symmetry xyz')
               If (inum == 2)   {
                                n  = AtoI(c)
                     If(n == 5) dummy = print('illegal translation in symmetry xyz')
                     s[axis,3] = Mod(10.+ Float(sign*m)/Float(n), 1.)
                     sign      = 1
               }
               inum += 1
       }  }
                          SeitzFromJones = s
    }

Category:
function