12.2 Functional list of commands

Program control

Command   Description 
 @ 		 		  Execution of a macrofile 
 = 		 		  Assigns the value of an expression to a variable 

break 		 		  Interrupts a loop or conditional statement 

continue 		 		  Continues DISCUS after 'stop' command


do 		 		  Start of a do loop 

else 		 		  Default block in an if  construction 

elseif 		 		  Alternative block in an if  construction 

enddo 		 		  End of a do loop  

endif 		 		  End of an if construction 

exit 		 		  Ends the DISCUS program 

if 		 		  Begin of an if construction 

learn 		 		  Starts a learn sequence 

lend 		 		  Ends a learn sequence 

seed 		 		  Initialize the random number generator 

set 		 		  Set various parameters 

stop 		 		  Stops DISCUS macro, resume with 'cont' 

system 		 		  Executes a shell command 

wait 		 		  Wait for user input 

Crystallographic calculations

Command   Description 

d2r 		 		  Converts a vector from real to reciprocal space  

proj 		 		  Project a vector onto another or onto a plane  

r2d 		 		  Converts a vector from reciprocal to real space 

vprod 		 		  Calculates the vector product 

Modification of individual atoms

Command   Description 

append 		 		  Appends an atom or molecule, if location is not occupied 

copy 		 		  Copies an atom 

ins 		 		  Inserts an atom 

kick 		 		  Deletes atom/molecule  and inserts a new one 

remove 		 		  Deletes an atom from the crystal 

switch 		 		  Switches the position of two atoms or molecules 
 m[j]=<exp> 		 		  Change scattering type of atom j to  value of                   expression 
 x[j]=<exp> 		 		  Change x position  of atom j to  value of expression 
 y[j]=<exp> 		 		  Change y position  of atom j to  value of expression 
 z[j]=<exp> 		 		  Change z position  of atom j to  value of expression 

Structure modifications at large

Command   Description 

mc 		 * 		  Switches to the Monte Carlo simulation level 

micro 		 * 		  Switches to the microdomain level of DISCUS 

purge 		 		  Deletes empty lines from the crystal 

replace 		 		  Replaces atom/molecule with given probability with                   a new type 

stack 		 * 		  Switches to Stacking fault sublevel of DISCUS 

symm 		 * 		  Switches to symmetry calculation sublevel of                   DISCUS 

thermal 		 		  Introducing displacements according to the temperature                   factor 

trans 		 * 		  Switches to the unit cell transformation segment 

wave 		 * 		  Switches to the wave generating level of DISCUS 

Fourier levels

Command   Description 

diff 		 * 		  Switches to the Difference Fourier level of DISCUS 

fourier 		 * 		  Switches to the Fourier level of DISCUS 

inverse 		 * 		  Switches to the Inverse Fourier Level of DISCUS 

patterson		 * 		  Switches to the Patterson level of DISCUS 

powder 		 * 		  Switches to the powder diffraction level of DISCUS 

Input and Output

Command   Description 

addfile 		 		  Adds the contents of two files 

output 		 * 		  Switches to the output level of DISCUS 

plot 		 * 		  Writes the structure in a format ready for display 

read 		 * 		  Switches to the reading level of DISCUS 

save 		 		  Saves the current structure to file 

Information and crystal analysis

Command   Description 
 # 		 		  Comment, the rest of the line will be ignored 

asym 		 		  Shows the content of the asymmetric unit 

chem 		 * 		  Switches to the chemistry level of DISCUS 

echo 		 		  Echoes a string 

eval 		 		  Evaluates an expression for interactive display 

eval n[1] 		 		  Displays the number of atoms within the crystal 

eval n[2] 		 		  Displays the number of different atoms within the                   crystal 

eval n[3] 		 		  Displays the number of atoms in (original) unit cell 

eval n[4] 		 		  Displays the number of molecules within the crystal  

eval n[5] 		 		  Displays the number of different molecule types within the                   the crystal 

eval n[6] 		 		  Displays the number of molecules in (original) unit cell 

eval m[<i>] 		 		 Displays atom type of atom <i> 

eval x[<i>] 		 		 Displays x-coordinate of atom <i>,                       similar for y and z


find 		 		  Finds the environment around an atom 

help 		 		  Gives on line help 

rmc 		 * 		  Switches to the Reverse Monte Carlo level of DISCUS 

pdf 		 * 		  Switches to the PDF level of DISCUS 

set 		 		  Set various parameters 

show 		 		  Displays various DISCUS settings and results