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The interactive command prompt is "Enter command: ".
Commands are read one at a time, parsed, and executed. By default, a line is expected to contain a complete command, so no special end-of-command token is needed.
Multi-line commands may be entered by enclosing them in braces {...}. If a line ends while nested in braces or parenthesis, Evolver will ask for more input with the prompt "more> ". It will also ask for more if the line ends with certain tokens (such as `+') that cannot legally end a command. Unclosed quotes will also ask for more, and embedded newlines will be omitted from the final string. Explicit continuation to the next line may be indicated by ending a line with a backslash (linesplicing). You may want to use the read command to read long commands from a file, since there is no command line editing.
Successfully parsed commands are saved in a history list, up to 100 commands. They may be accessed with !! for the last command or !string for the latest command with matching initial string. !n will repeat a command by history list number. The command will be echoed. The saved history list may be printed with the history command.
Some single-letter commands require interactive input. For those, there are equivalent commands that take input information as part of the command. This is so commands may be read from a script without having to put input data on additional lines after the command, although that can still be done for the single-letter versions.
General note: Some commands will prompt you for a value. A null response (just RETURN) will leave the old value unchanged and return you to the command prompt. On options where a zero value is significant, the zero must be explicitly entered. Commands that need a real value will accept an arbitrary expression.
Many commands that change the surface or change the model will cause energies and volumes to be recalculated. If you suspect a command has not done this, the recalc command will recalculate everything. It will also update any automatic display.
In the command syntax descriptions, keywords are shown in upper case, although case is irrelevant in actual commands, except for single-letter commands.
g 10; r; g 10; u myc := { print 5; g 10; if qwer < foo then print 3 else { print 2; print 4; }; aa := 23 }
if ( foo > 4 ) then { g;g;u; } else print 4; while ( xx < 2 ) do { g; xx := xx + 1 } aa := { g 5; foreach vertex vv do { printf "id: %g coord: %f %f %f\n",id,x,y,z; count := count + 1; }; // note semicolon here! printf "done.\n" }
g 10 U 2 { g 20; u; V; u } 20 myc := { g 20; V }; myc 10
quantityname.modulus := expr quantityname.target := expr quantityname.volconst := expr
instancename.modulus := expr
identifier := commandThe shortest complete command on the right side is used. Thus "gg := g 10; u" would give gg the same value as "gg := g 10". It is wise and strongly advised to use braces to enclose the command on the right side so the parser can tell it's a command and not an expression. Also multiline commands then don't need linesplicing. Do not try to redefine single-letter commands this way; use :::=. Example:
gg := {g 10; u}
procedure identifier ( type arg1, type arg2, ... ) { commands }Right now the implemented types for arguments are real and integer. The argument list can be empty. Example:
procedure proc1 ( real ht, real wd ) { prod := ht*wd; // this would make prod a global variable return; }Note that the procedure arguments act as local variables, i.e. their scope is the procedure body, and they have stack storage so procedures may be recursive. Procedure prototypes may be used to declare procedures before their bodies are defined with the same syntax, just replacing the body of the procedure with a semicolon. Prototype syntax:
procedure identifier ( type arg1, type arg2, ... );Note that a procedure is used as a command, and a function is used in a numerical expression.
function type identifier ( type arg1, type arg2, ... ) { commands }Right now the implemented types for return value and arguments are real and integer. The argument list can be empty. The return value is given in a return expr statement. Example:
function real func1 ( real ht, real wd ) { local prod; prod := ht*wd; return prod; }Note that the function arguments act as local variables, i.e. their scope is the function body, and they have stack storage so functions may be recursive. Function prototypes may be used to declare functions before their bodies are defined with the same syntax, just replacing the body of the function with a semicolon. Prototype syntax:
function type identifier ( type arg1, type arg2, ... );Note that a procedure is used as a command, and a function is used in a numerical expression.
identifier := expr identifier := stringexprIf the variable does not exist, it will be created. These are the same class of variables as the adjustable parameters in the datafile, hence are all of global scope and may also be inspected and changed with the 'A' command. Examples:
maxlen := max(edge,length) newname := sprintf "file%03g",counter
do_stuff := { local inx; for ( inx := 1 ; inx < 5 ; inx += 1 ) { local jnx; jnx := inx*2; print jnx; }; }Using local variables is good for avoiding pollution of global namespace and for writing recursive functions (storage space for locals is allocated on the runtime stack). Note that the local declaration is a scope declaration, not a type declaration. Also, it cannot be combined with initialization of the variable (yet), and there is one name per declaration. Function arguments also act as local variables.
command >> stringexprThe output of a command can be redirected to a file with the symbol '>>>'. This overwrites an existing file. Syntax:
command >>> stringexprRedirection with `>' is not available due to the use of `>' as an comparison operator. The output of a command can be piped to a system command using the unix-style pipe symbol `|'. Syntax:
command | stringexprThe stringexpr is interpreted as a system command.
Examples:
list facets | "more" list vertices | "tee vlist" ; g 10 | "tee g.out" { {g 10; u } 20 } >> "logfile" {foreach facet do print area} | "cat >areafile"
IF expr THEN command IF expr THEN command ELSE commandexpr is true if nonzero. Parentheses around expr are not needed, but do not hurt. Do not use a semicolon to end the first command. Example:
if max(edges,length) > 0.02 then {r; g 100} else g 4
WHILE expr DO commandexpr is true if nonzero. Parentheses around expr are not needed, but do not hurt. Example:
count := 0 while count < 10 do { g 10; u; print total_energy; count := count + 1 }
DO command WHILE exprexpr is true if nonzero. Parentheses around expr are not needed, but do not hurt. Example:
do { oldenergy := total_energy; g 10 } while (oldenergy-total_energy < 1e-6)
FOR ( command1 ; expr ; commmand2 ) command3The first command is the initialization command; note that it is a single command, rather than an expression as in C. If you want multiple commands in the initialization, use a compound command enclosed in curly braces. The middle expression is evaluated at the start of each loop iteration; if its value is true (i.e. nonzero) then the loop is executed; otherwise the flow of control passes to the command after command3. The command2 is executed at the end of each loop iteration; again, it is a single command. The body of the loop is the single command command3, often a compound] command. Note: Command3 should end with a semicolon, unless it is the if clause of an if-then statement. Examples:
for ( inx := 1 ; inx < 3 ; inx += 1 ) print facet[inx].area; for ( {inx := 1; factorial := 1; } ; inx < 7 ; inx += 1 ) { factorial *= inx; printf "factorial %d is %d\n",inx,factorial; };
FOREACH generator DO commandExamples:
foreach vertex do print x^2 + y^2 + z^2 foreach edge ee where ee.dihedral > .4 do { printf "id %g\n",id; foreach ee.vertex do printf " %g %g %g\n",x,y,z; }
BREAK BREAK nThe first form exits the innermost current loop. The second form exits n loops. Note: Commands with repetition counts do not qualify as loops. Example:
foreach vertex do { print x; if y < 0 then break; print z }
CONTINUE CONTINUE nThe second form exits the innermost n-1 loops, and skips to the loop control of the nth innermost loop. Note: Commands with repetition counts do not qualify as loops. Example:
foreach vertex vv do { foreach vv.edge do { print length; if length < .4 then continue 2; } }
if ( acc < 1.e-10 ) then return;
elementgen name where exprelementgen may be
list facet where color == red foreach edge ee where ee.length < .3 do list ee.vertex print facet[2].edge[1].vertex[2].id foreach facet ff do { printf "facet %g:\n"; list ff.edge } print max(edge where on_constraint 1, length)
AREAWEED exprSame as 'w' command, except does not need interactive response. Also same as "delete facets where area < expr". Examples:
areaweed 0.001 areaweed 2*min(facet,area)
BINARY_PRINTF string,expr,expr,...Prints to standard output using a binary interpretation of the standard C formats:
binary_printf "%ld%ld%ld",vertex_count,edge_count,facet_count >>"out.bin"
BODY_METIS nExample:
body_metis 50; // supposing we have thousands of bodies, say for each body bb do set bb.facet frontcolor (bb.bpart imod 15)+1;
CHDIR stringexprIn MS-Windows, use a front slash '/' or a double backslash '\\' instead of a single backslash as the path character. Example:
chdir "/usr/smith/project"
DEFINE variable typewhere type is REAL, INTEGER, or STRING. Note that this way of declaring a variable does not take an initial value; thus it is a way of making sure a variable is defined without overwriting an existing value of the variable. The syntax for defining arrays and extra attributes is the same as in the top of the datafile; for constraints, boundaries, named quantities, and method instances, it is the same as in the top of the datafile except the word "define" comes first. Multi-line definitions should be enclosed in brackets and terminated with a semicolon. Or they can be enclosed in quotes and fed to the exec command. Of course, using exec means the parser doesn't know about the define until the exec is executed, so you cannot use the defined item in commands until then. It is legal to re-define an existing array or array extra attribute with different dimensions (but the same number of dimensions); data will be preserved as best as possible in the resized array. An array may be given the dimension 0 to free its memory allocation. Examples:
define fudge_factor real define pqlist real[imax][jmax] define edge attribute charlie real define vertex attribute oldx real[3] define facet attribute knots real[5][5][5] { define constraint frontcon formula z = 0 energy: e1: -y/2 e2: x/2 e3: 0; } exec "define boundary newboundary parameters 1 x: sin(p1) y: cos(p1) z: 3" exec "define quantity qarea info_only method facet_area global"
DELETE generatorDeletes edges by shrinking the edge to zero length (as in the tiny edge weed command t) and facets by eliminating one edge of the facet. Facet edges will be tried for elimination in shortest to longest order. Edges will not be deleted if both endpoints are fixed, or both endpoints have different constraints or boundaries from the edge. DELETE maintains the continuity and connectedness of the surface, as opposed to DISSOLVE. Example:
delete facets where area < 0.0001
DISSOLVE generatorThe effect is the same as if the line for the element were erased from a datafile. Hence no element will be dissolved that is used by a higher dimensional element. (There are three exceptions: dissolving an edge on a facet in the string model, and dissolving a facet on one body or with both adjacent bodies the same in the soapfilm model.) Thus "dissolve edges; dissolve vertices" is safe because only unused edges and vertices will be dissolved. No error messages are generated by doing this. Good for poking holes in a surface. Example:
dissolve facets where original == 2; dissolve edges; dissolve verticesThus "dissolve edges; dissolve vertices" is safe because only unused edges and vertices will be dissolved. No error messages are generated by doing this.
DUMP filenameThe filename is a string. With no filename, dumps to the default dump file, which is the current datafile name with ".dmp" extension. Same as the 'd' command, except 'd' requires a response from the user for the filename. Examples:
dump "foo.dmp" dump sprintf "%s.%g.dmp",datafilename,counter
edge_merge(integer,integer)Note the arguments are signed integer ids for the elements, not element generators. The tails of the edges are merged, and so are the heads. Orientation is important. Example:
edge_merge(3,-12)
EDGESWAP edgegeneratorIf any of the qualifying edges are diagonals of quadrilaterals, they are flipped in the same way as in equiangulation, regardless of whether equiangularity is improved. "edgeswap edge" will try to swap all edges, and is not recommended, unless you like weird things. Various conditions will prevent an edge from being swapped:
edgeswap edge[22] edgeswap edge where color == red
EDGEWEED exprSame as 't' command, except does not need interactive response. Same as "delete edge where length < expr".
EIGENPROBE expr EIGENPROBE(expr,expr)The first form prints the number of eigenvalues of the energy Hessian that are less than, equal to, and greater than expr. It is OK to use an exact eigenvalue (like 0, often) for the value, but not really recommended. Useful for probing stability. Second form will further do inverse power iteration to find an eigenvector. The second argument is the limit on the number of iterations. The eigenvalue will be stored in the last_eigenvalue internal variable, and the eigenvector can be used by the move command. The direction of the eigenvector is chosen to be downhill in energy, if the energy gradient is nonzero.
EQUIANGULATE edge_generatorExamples:
equiangulate edge[3]; equilangulate edge where color == red;
EXEC stringexprExample:
exec sprintf "define vertex attribute prop%d real",propnumber
EXPRINT commandnameExample:
Enter command: aa := { print 5; /* this is a test */ } Enter command: exprint aa { print 5; /* this is a test */ }
facet_merge(integer,integer)Note the syntax is a function taking signed integer facet id arguments, not element generators. IMPORTANT: The frontbody of the first facet should be equal to the backbody of the second (this includes having no body); this is the body that will be squeezed out when the facets are merged. If this is not true, then facet_merge will try flipping the facets orientations until it finds a legal match. Example:
facet_merge(3,-12)
FIX generatorExample:
fix vertices where on_constraint 2Can also convert a parameter from optimizing to non-optimizing. Example:
fix radiusCan also convert a named quantity from info_only to fixed. See also unfix.
geompipe stringexprThe redirection can be closed with the command "P 9". geompipe is useful for debugging geomview data; but be sure to toggle gv_binary OFF to get ascii data to look at.
geomview stringexprwill send a command to an already started geomview. This string must be in the geomview command language, for which consult the geomview documentation.
help keywordThe keyword need not be in quotes, unless there are embedded blanks. After printing the help section exactly matching the keyword, a list of related terms is printed. These are just the keywords containing your keyword as a substring.
The built-in browser is in no way a complete substitute for using a full-fledged browser such as Netscape or Mosaic.
HESSIAN_SEEK maxscalewhere maxscale is an optional upper bound for the distance to seek. The default maxscale is 1, which corresponds to a plain hessian step. The seek will look both ways along the direction, and will test down to 1e-6 of the maxscale before giving up and returning a scale of 0. This command is meant to be used when the surface is far enough away from equilibrium that the plain hessian command is unreliable, as hessian_seek guarantees an energy decrease, if it moves at all.
HISTOGRAM(generator, expr) LOGHISTOGRAM(generator, expr)Prints a histogram of the values of expr for the generated elements. It uses 20 bins evenly divided between minimum and maximum values. It finds its own maximum and minimum values, so the user does not have to specify binsize. The log version will lump all zero and negative values into one bin. Examples:
histogram(edge,dihedral*180/pi) loghistogram(facet where color == red, area) histogram(vertex where on_constraint 1, sqrt(x^2+y^2+z^2))
LAGRANGE nwhere n is the lagrange_order, which is between 1 and some built-in maximum (currently 8). This command can also convert between Lagrange models of different orders. Note that lagrange 1 gives the Lagrange model of order 1, which has a different internal representation than the linear model. Likewise, lagrange 2 does not give the quadratic model.
LANCZOS expr LANCZOS (expr,expr)Does a little Lanczos algorithm and reports the nearest approximate eigenvalues to the given probe value. In the first form, expr is the probe value, and 15 eigenvalues are found. In the second form, the first argument is the probe value, the second is the number of eigenvalues desired. The output begins with the number of eigenvalues less than, equal to, and greater than the probe value. Then come the eigenvalues in distance order from the probe. Not real polished yet. Beware that multiplicities reported can be inaccurate. The eigenvalue nearest the probe value is usually very accurate, but others can be misleading due to incomplete convergence. Since the algorithm starts with a random vector, running it twice can give an idea of its accuracy.
LIST generator LIST constraintname LIST CONSTRAINT constraintnumber LIST boundaryname LIST BOUNDARY boundarynumber LIST quantityname LIST instancenameOn unix systems, piping to more can be used for long displays. Examples:
list edges where id <= 12 list vertices | "more" list vertices where x < 1 and y > 2 and z >= 3 | "tee vfile" list facet[3] list facet[3].edges where on_constraint 1 list facet[3].edge[2].vertex[1] list constraint 1See also LIST ATTRIBUTES, LIST BOTTOMINFO, LIST PROCEDURES, and LIST TOPINFO.
LOAD filenameTerminates the current surface and loads a new datafile. The filename is the datafile name, and can be either a quoted string or a string variable. This completely re-initializes everything, including the command interpreter. In particular, the currently executing command ends. Useful only as the last command in a script. For loading a new surface and continuing with the current command, see permload. Wildcard matching is in effect on some systems (Windows, linux, maybe others), but be very careful when using wildcards since there can be unexpected matches.
LOGFILE stringexpr LOGFILE OFFStarts recording all input and output to the file specified by stringexpr, which must be a quoted string or a string variable or expression. Appends to an existing file. To end logging, use logfile off. To record just input keystrokes, use keylogfile.
KEYLOGFILE stringexpr KEYLOGFILE OFFStarts recording all input keystrokes to the file specified by stringexpr, which must be a quoted string or a string variable or expression. Appends to an existing file. To end logging, use keylogfile off. To record both input and output, use logfile.
METIS n KMETIS nExample:
metis 20; set facet color (fpart imod 15) + 1;For partitioning bodies, see body_metis.
LONGJ
Main prompt command. For perturbing the surface. This does a "long jiggle", which provides long wavelength perturbations that can test a surface for stability. The parameters are a wavevector, a phase, and a vector amplitude. The user will be prompted for values. Numbers for vectors should be entered separated by blanks, not commas. An empty reply will accept the defaults. A reply of r will generate random values. Any other will exit the command without doing a jiggle. In the random cases, a random amplitude $\vec A$ and a random wavelength $\vec L$ are chosen from a sphere whose radius is the size of the object. The wavelength is inverted to a wavevector $\vec w$. A random phase $\psi$ is picked. Then each vertex $\vec v$ is moved by $\vec A\sin(\vec v \cdot \vec w + \psi)$. This command is archaic. More control over perturbations may be had with the "set vertex x ..." type of command.
MATRIX_INVERSE
Main prompt command. For computing the inverse of a square matrix. Currently applies only to global matrices, not element attribute matrices. Syntax:MATRIX_INVERSE(matrix1, matrix2)Here matrix1 is the name of the original matrix, and matrix2 is the name of the inverse matrix. They may be the same matrix to get an in-place inverse. Examples:define mata real[5][5] define matb real[5][5] ... // fill in values of mata matrix_inverse(mata,matb) matrix_inverse(mata,mata)
MATRIX_MULTIPLY
Main prompt command. For computing the product of matrices. Currently applies only to global matrices, not element attribute matrices. Syntax:MATRIX_MULTIPLY(matrix1, matrix2, matrix3)Here matrix1 and matrix2 are the names of the multiplicands, and matrix3 is the name of the product matrix. The product matrix may be the same as one (or both) of the multiplicands. The matrices can be one-dimensional or two-dimensional, so you can do vector-matrix or matrix-vector multiplication (but you can't do vector times vector). Examples:define mata real[5][5] define matb real[5][5] define matc real[5][5] ... // fill in values of mata and matb matrix_multiply(mata,matb,matc) matrix_multiply(mata,mata,mata)
MOVE
Main prompt command. For moving along the current direction of motion. Syntax:MOVE exprMoves the surface along the previous direction of motion by the stepsize given by expr. The previous direction can be either from a gradient step (g command) or a hessian step (hessian, saddle, hessian_seek, hessian_menu option 4, etc.). The stepsize does not affect the current scale factor. A negative step is not a perfect undo, since it cannot undo projections to constraints. "Move" sometimes does not work well with optimizing parameters and hessian together.
NEW_VERTEX
Main prompt command. For creating a new vertex. The syntax is that of a function instead of a verb, since it returns the id number of the new vertex. The arguments are the coordinates of the vertex. The new vertex is not connected to anything else; use the new_edge command to connect it. Syntax:newid := NEW_VERTEX(expr, expr,...)Examples:newid1 := new_vertex(0,0,1) newid2 := new_vertex(pi/2,0,max(vertex,x))
NEW_EDGE
Main prompt command. For creating a new edge. The syntax is that of a function instead of a verb, since it returns the id number of the new edge. The arguments are the id's of the tail and head vertices. Syntax:newid := NEW_EDGE(expr, expr)The new edge has the same default properties as if it had been created in the datafile with no attributes, so you will need to explicitly add any attributes you want. Example to create a set of coordinate axes in 3D:newv1 := new_vertex(0,0,0); fix vertex[newv1]; newv2 := new_vertex(1,0,0); fix vertex[newv2]; newv3 := new_vertex(0,1,0); fix vertex[newv3]; newv4 := new_vertex(0,0,1); fix vertex[newv4]; newe1 := new_edge(newv1,newv2); fix edge[newe1]; newe2 := new_edge(newv1,newv3); fix edge[newe2]; newe3 := new_edge(newv1,newv4); fix edge[newe3]; set edge[newe1] no_refine; set edge[newe1] bare; set edge[newe2] no_refine; set edge[newe2] bare; set edge[newe3] no_refine; set edge[newe3] bare;
NEW_FACET
Main prompt command. For creating a new facet. The syntax is that of a function instead of a verb, since it returns the id number of the new facet. The arguments are the oriented id's of the edges around the boundary of the facet, in the same manner that a face is defined in the datafile. The number of edges is arbitrary, and they need not form a closed loop in the string model. In the soapfilm model, if more than three edges are given, the new face will be triangulated by insertion of a central vertex. In that case, the returned value will be the original attribute of the new facets. In the simplex model, the arguments are the id's of the facet vertices. Syntax:newid := NEW_FACET(expr, expr,...)The new facet has the same default properties as if it had been created in the datafile with no attributes, so you will need to explicitly add any attributes you want. Example:newf := new_facet(1,2,-3,-4); fix facet where original == newf;
NEW_BODY
Main prompt command. For creating a new body. The syntax is that of a function instead of a verb, since it returns the id number of the new body. There are no arguments. Syntax:newid := NEW_BODYThe body is created with no facets. Use the set facet frontbody and set facet backbody commands to install the body's facets. The new body has the same default properties as if it had been created in the datafile with no attributes, so you will need to explicitly add any attributes you want, such as density or target volume. Example:newb := new_body set facet frontbody newb where color == red
NOTCH
Main prompt command. For refining a surface in regions of high curvature. Syntax:NOTCH exprNotches all edges with dihedral angle greater than given value. Same as 'n' command, orforeach edge ee where ee.dihedral > expr do refine ee.facetNotching is done by adding a vertex in the middle of adjacent facets. Should be followed by equiangulation.
OMETIS
Main prompt command. Computes an ordering for Hessian factoring using the METIS library of Karypis and Kumar, if this library has been compiled into the Evolver (not part of the public distribution yet). Prints ordering tree. To actually use METIS ordering during factoring, use the toggle metis_factor. Note: ometis no longer works for Metis version 3 or later, since Metis does not return the tree any more. But metis_factor still works. Syntax:OMETIS n // n is smallest partition size OMETIS // defaults to n = 100
OOGLFILE
Main prompt command. Writes a file containing OOGL-formatted graphics data for the surface as a POLY or CPOLY quad file. This is a non-interactive version of the P 2 command. Syntax:ooglfile stringexprThe string gets ".quad" appended to form the filename. This command does not ask any of the other questions the P 2 command asks; it uses the default values, or whatever the last responses were to the previous use of the interactive P 2 command. Good for use in scripts. Example:ooglfilename := sprintf "frame%d",framecounter; ooglfile ooglfilename; framecounter += 1;
OPTIMIZE
Main prompt command. Set gradient descent iteration to optimizing mode, with an upper bound on the scale factor. "Optimise" is a synonym. Syntax:OPTIMIZE expr
PAUSE
Main prompt command. Pauses execution until the user hits RETURN. Useful in scripts to give the user a chance to look at some output before proceeding.
PERMLOAD
Main prompt command. Loads a new datafile and continues with the current command after the read section of the datafile finishes. The filename is the datafile name, and can be either a quoted string or a string variable. Since the automatic re-initialization makes Evolver forget all non-permanent variables, care should be taken that the current command only uses permanently assigned variables (assigned with ::= ). Useful for writing scripts that run a sequence of evolutions based on varying parameter values. Using permload is a little tricky, since you don't want to be redefining your permanent commands and variables every time you reload the datafile, and your permanent command cannot refer directly to variables parameterizing the surface. One way to do it is to read in commands from separate files. For example, the catenoid of cat.fe has height controlled by the variable zmax. You could have a file permcat.cmd containing the overall series script commandrun_series ::= { for ( height ::= 0.5 ; height < 0.9 ; height ::= height + .05 ) { permload "cat"; read "permcat.gogo"; } }and a file permcat.gogo containing the evolution commandsu; zmax := height; recalc; r; g 10; r; g 10; hessian; printf "height: %f area: %18.15f\n",height,total_area >> "permcat.out";Then at the Evolver command prompt,Enter command: read "permcat.cmd" Enter command: run_seriesFor loading a new surface and not continuing with the current command, see load. Wildcard matching is in effect on some systems (Windows, linux, maybe others), but be very careful when using wildcards since there can be unexpected matches.
POP
Main prompt command. Pops an individual edge or vertex or set of edges or vertices, giving finer control than the universal popping of the O and o commands. The specified vertices or edges are tested for not being minimal in the soap film sense. For vertices, this means having more than four triple edges adjacent; higher valence edges are automatically popped. For edges, this means having more than three adjacent facets when not on constraints or otherwise restricted. It tries to act properly on constrained edges also, but beware that my idea of proper behavior may be different from yours. Normally, popping puts in new edges and facets to keep originally separated regions separate, but that behavior can be changed with the pop_disjoin toggle. The style of popping a cone over a triangular prism can be controlled with the pop_to_edge and pop_to_face commands. The pop_enjoin toggle forces joining cones to be popped by widening the vertex into a neck. Examples:pop edge[2] pop edge where valence==5
POP_EDGE_TO_TRI
Main prompt command. This command does a particular topological transformation common in three-dimensional foam evolution. An edge with tetrahedral point endpoints is transformed to a single facet. A preliminary geometry check is made to be sure the edge satisfies the necessary conditions, one of which is that the triple edges radiating from the endpoints have no common farther endpoints. If run in verbose mode, messages are printed when a specified edge fails to be transformed. This command is the inverse of the pop_tri_to_edge command. Works in linear and quadratic mode. Examples:pop_edge_to_tri edge[2] pop_edge_to_tri edge where valence==3 and length < 0.001
POP_QUAD_TO_QUAD
Main prompt command. This command does a particular topological transformation common in three-dimensional foam evolution. A quadrilateral bounded by four triple edges is transformed to a quadrilateral oriented in the opposite direction. The shortest pair of opposite quadrilateral edges are shrunk to zero length, converting the quadrilateral to an edge, then the edge is expanded in the opposite direction to form the new quadrilateral. The new quadrilateral inherits attributes such as color from the first quadrilateral, although all the facet numbers are different. A preliminary geometry check is made to be sure the edge satisfies the necessary conditions, one of which is that the triple edges radiating from the quadrilateral corners have no common farther endpoints. If run in verbose mode, messages are printed when a specified quadriteral fails to be transformed. The specified facet can be any one of the facets of the quadrilateral with a triple line on its border. It doesn't hurt to apply the command to all the facets of the quadrilateral, or to facets of multilple quadrilaterals. Quadrilaterals may be arbitrarily subdivided into facets; in particular, they may have some purely interior facets. Works in linear and quadratic mode. Examples:pop_quad_to_quad facet[2] pop_quad_to_quad facet where color==red
POP_TRI_TO_EDGE
Main prompt command. This command does a particular topological transformation common in three-dimensional foam evolution. A facet with three tetrahedral point vertices is transformed to a single facet. A preliminary geometry check is made to be sure the edge satisfies the necessary conditions, one of which is that the triple edges radiating from the vertices have no common farther endpoints. If run in verbose mode, messages are printed when a specified edge fails to be transformed. This command is the inverse of the pop_edge_to_tri command. Works in linear and quadratic mode. Examples:pop_tri_to_edge facet[2] pop_tri_to_edge facet where color == red
POSTSCRIPT
Main prompt command. Creates a PostScript file of the current surface in a file. Syntax:POSTSCRIPT stringexprThe string gives the name of the file; a .ps extension will be appended if it is missing. It is the same as the P option 3 command, except that there are no interactive responses needed. Output options are controlled by the ps_colorflag, gridflag, crossingflag, and labelflag toggles. full_bounding_box toggles.
PRINT expr PRINT stringexpr PRINT commandname PRINT arrayslice PRINT WARNING_MESSAGESThe arrayslice option takes an array name or a partially indexed array name. If more than one element results, the slice is printed in nested curly braces. The arrayslice can also be that of an array attribute of an element. The warning_messages option is handy for reviewing warning messages that occur early in the loading of a datafile but scroll off the screen too rapidly to see. PRINT expr can also be used inside an expression, where it prints the expression and evaluates to the value of its expression. Examples:print datafilename; print max(edge,length); print max(vertex, print (x^2+y^2+z^2) ); gg := {list vertex where id < 10; g 5}; print gg; define parts real[3][2][3]; print parts; print parts[3][2];
PRINTF
Main prompt command. For printing formatted output. Syntax:PRINTF string,expr,expr,...Prints to standard output using the standard C sprintf function. All string, integer, and floating point formats are valid. Integer formats force floating point arguments to be converted to integer. The format string can be a string variable or a quoted string. There is a limit of 1000 characters on the format string, otherwise there is no limit on the number of arguments. Example:printf "This is %s with total energy %f\n",datafilename,total_energy
QUADRATIC
Main prompt command. Changes to quadratic model from linear or Lagrange models.
QUIT, BYE, EXIT
Main prompt command. Exits Evolver or starts new datafile. Same as `q' command.
RAWESTV
Main prompt command. Does vertex averaging for all vertices without regard for conserving volume or whether averaged vertices have like constraints. But doesn't move vertices on boundaries. To do a selected group of vertices, use rawest_vertex_average.
RAWEST_VERTEX_AVERAGE
Main prompt command. Does vertex averaging on selected vertices without conserving volume on each side of surface, or attention to being on like constraints. Doesn't move vertices on boundaries. Using the verbose toggle will print messages. Syntax:RAWEST_VERTEX_AVERAGE generatorExample:rawest_vertex_average vertex[3]
RAWV
Main prompt command. Does vertex averaging for all vertices without conserving volume on each side of surface. Will only average vertices with those of like type of constraints. Doesn't move vertices on boundaries. To do a selected group of vertices, use raw_vertex_average.
RAW_VERTEX_AVERAGE
Main prompt command. Does vertex averaging on selected vertices without conserving volume on each side of surface. Will only average vertices with those of like type of constraints. Doesn't move vertices on boundaries. Using the verbose toggle will print messages. Syntax:RAW_VERTEX_AVERAGE generatorExample:raw_vertex_average vertex where valence == 6
READ
Main prompt command. For reading commands from a file. Syntax:READ filenameThe filename can be either a quoted string or a string variable. The effect is as if the file were typed in at the keyboard. Hence main commands, responses to commands, and graphics mode commands can be included. Read commands may be nested. On the occurence of an error, input reverts to the original standard input. Example:read "zebra.cmd"
REBODY
Main prompt command. Recalculates connected bodies. Useful after a body has been disconnected by a neck pinching off. Facets of an old body are divided into edge-connected sets, and each set defines a new body (one of which gets the old body id). The new bodies inherit the attributes of the old body. If the original body volume was fixed, then the new bodies' target volumes become the new actual volumes. If the original body had a volconst, the new bodies will inherit the same value. This will likely lead to incorrect values, so you will have to adjust the volconsts by hand. In commands, you may specify the new bodies descended from an original body by using the 'original' atttribute.
RECALC
Main prompt command. Recalculates and redisplays everything. Useful after changing some variable or something and recalculation is not automatically done. Evolver tries to automatically recalculate when some significant change is made, but doesn't always know. Also see autorecalc.
REFINE
Main prompt command. For subdividing sets of edges or facets. Syntax:REFINE generatorSubdivides the generated edges or facets. Subdivides edges by putting a vertex in the middle of each edge, and splitting neighboring facets in two in the soapfilm model. It is the same action as the long edge subdivide command (command l). Facets will be subdivided by putting a vertex in the center and creating edges out to the old vertices. It is strongly suggested that you follow this with equiangulation to nicen up the triangulation. Edge refinement is better than facet refinement as facet refinement can leave long edges even after equiangulation. This command does not respect the no_refine attribute. Example:refine edges where not fixed and length > .1
RESET_COUNTS
Main prompt command. Resets to 0 various internal counters. The counters are:
REVERSE_ORIENTATION generatorReverses the internal orientation of selected edges or facets, as if they had been entered in the datafile with the opposite orientation. Useful, for example, when edges come in contact with a constraint and you want to get them all oriented in the same direction. Relative orientations of constraint and quantity integrals change to compensate, so energy, volumes, etc. should be the same after the command, but it would be wise to check in your application. Examples:
reverse_orientation edge[7] reverse_orientation facets where backbody != 0
RITZ(expr,expr)Applies powers of inverse shifted Hessian to a random subspace to calculate eigenvalues near the shift value. First argument is the shift. Second argument is the dimension of the subspace. Prints out eigenvalues as they converge to machine accuracy. This may happen slowly, so you can interrupt it by hitting whatever your interrupt key is, such as CTRL-C, and the current values of the remaining eigenvalues will be printed out. Good for examining multiplicities of eigenvalues. It is legal to shift to an exact eigenvalue, but not wise, as they will not be printed. See the Hessian tutorial for more. The first eigenvalue is subsequently available in the last_eigenvalue internal variable. The full list of eigenvalues produced is subsequently available in the eigenvalues[] array. Example: To get the lowest 5 eigenvalues of a Hessian you know is positive definite:
ritz(0,5)
define vertex attribute vertex_order_key real define edge attribute edge_order_key real define facet attribute facet_order_key real define body attribute body_order_key real define facetedge attribute facetedge_order_key real reorder := { set vertex vertex_order_key x+y+z; set edge ee edge_order_key min(ee.vertex,vertex_order_key); set facetedge fe facetedge_order_key fe.edge[1].edge_order_key; set facet ff facet_order_key min(ff.vertex,vertex_order_key); set body bb body_order_key min(bb.facet,facet_order_key); reorder_storage; }
SADDLE exprwill limit the step size to expr. The motion vector is available afterwards through the move command.
SET elementtype [name] attrib expr1 where expr2 SET elementtype.attrib expr1 where expr2 SET name attrib expr SET name.attrib expr SET quantityname attrib expr SET instancename attrib exprThe first two forms set the value of the attribute attrib to the value expr1 for all elements of the given type that satisfy expr2. elementtype can be vertex, edge, facet, or body, or any element generator without a where clause. The optional name refers to the element under consideration, and can be used in expr1 and expr2 to refer to attributes of that element. Even without name, attributes of the element can be referred to if the references are not nested in element generators in expr1 or expr2. The next two forms can be used inside an element generator which defines name. When name is not used, a '.' can be used, for those who like that sort of thing. SET can change the following attributes: constraint, coordinates, density, orientation, non-global named quantity or named method, user-defined extra attributes, body target volume, body volconst, fixed, frontbody, backbody, pressure, color, frontcolor, backcolor, boundary, and opacity (for the appropriate type elements). Fixed, named quantity, and named method attributes are just toggled on; they do not need the first expr. Setting the pressure on a body automatically unfixes its volume. For constraint, the expr is the constraint number. If using set to put a vertex on a parametric boundary, set the vertex's boundary parameters p1, p2, etc. first. Examples:
set facets density 0.3 where original == 2 set vertices x 3*x where id < 5 // multiplies x coordinate by 3 set body target 5 where id == 1 // sets body 1 target volume to 5 set vertices constraint 1 where id == 4 set facet color clear where original < 5 foreach facet ff do set ff color red define vertex attribute weight real; set vertex weight 3 set vertex quantity my_quantity set vertex[1].facet color redNote the first form of syntax has the attribute and new value in the middle of an element generator. Syntactically inconsistent with other commands that use element generators, but more natural English. Actually, the syntactically consistent
The last two forms set the value of a named quantity or named method instance attribute. For a named quantity, the settable attributes are target, modulus, volconst, and tolerance. For a named method instance, only modulus. There is no implicit reference to the quantity in the expression, so say
set myquant target myquant.valuerather than set myquant target value. Also see unset.
show edges where expr show facets where exprThe default is to show all facets, and to show all special edges: fixed edges, constraint edges, boundary edges, and edges without exactly two adjacent facets. The defaults can be restored with "show facets" and "show edges". Some graphics modules (like geomview) can show edges of facets on their own initiative. This is separate from the edge show criterion here; to show the colors of edges, the edges must satisfy the criterion. Show causes graphics to be redrawn. If a graphics display is not active, show will start screen graphics. Show_expr is the same as show in setting the show expressions, except it does not start graphics. Show alone will just start screen graphics. Examples:
show facets where color == red show edges where 1 show edges where color != black
show_trans "rrdd5z"
SPRINTF stringexpr,expr,expr,...Example:
dumpname := SPRINTF "file%04g.dmp",counter
SYSTEM stringexprInvokes a subshell to execute the given command, on systems where this is possible. Command must be a quoted string or a string variable. Will wait for command to finish before resuming.
TRANSFORM_DEPTH nwhere n is the maximum number of generators to multiply together. This will toggle immediate showing of transforms, if they are not already being shown.
a | Generates set {I,a}. |
!a | Generates set {a}. |
AB | Generates all ordered products of pairs from A and B. |
nA | Generates all n-fold ordered products. |
A|B | Generates union of sets A and B. |
(A) | Grouping; generates same set as A. |
transform_expr "3(a|b|c)" //all products of 3 or fewer generators transform_expr "abcd" // generates 16 transforms transform_expr "!a!a!a!a!" // generates one transformAll duplicate transforms are removed, so the growth of the sets does not get out of hand. Note the identity transform is always included. The letter denoting a single generator may be upper or lower case. The order of generators is the same as in the datafile. In the torus model, transforms along the three period vectors are always added to the end of the list of generators given in the datafile. If 26 generators are not enough for somebody, let me know. The current value of the expression may be accessed as a string variable, and the number of transformations generated can be accessed as transform_count. For example,
print transform_expr print transform_count
\_/ => \/ / \ | /\It will silently skip edges it is applied to that don't fulfill the two triple endpoint criteria, or whose flipping is barred due to fixedness or constraint incompatibilities. The number of edges flipped can be accessed through the t1_edgeswap_count internal variable. Running with the verbose toggle on will print details of what it is doing. Syntax:
T1_EDGESWAP edge_generatorExamples:
t1_edgeswap edge[23] t1_edgeswap edge where length < 0.1
UNFIX generatorExample:
unfix vertices where on_constraint 2Can also convert a parameter from non-optimizing to optimizing. Example:
unfix radiusCan also convert a named quantity from fixed to info_only.
UNSET elements [name] attrib where clauseUnsettable attributes are fixed (vertices, edges, or facets) , body target volume, body pressure, body gravitational density, non-global named quantities, non-global named methods, level-set constraints, parametric boundary. frontbody, or backbody. A use for the last is to use a boundary or constraint to define an initial curve or surface, refine to get a decent triangulation, then use "unset vertices boundary 1" and "unset edges boundary 1" to free the curve or surface to evolve. The form "unset facet bodies ..." is also available to disassociate given facets from their bodies. Examples:
unset body[1] target unset vertices constraint 1; unset edges constraint 1
VALID_ELEMENT(indexed_element)Examples:
if valid_element(edge[12]) then refine edge[12] if valid_element(body[2]) then set body[2].facet color red
VERTEX_AVERAGE vertex_generatorThe action is the same as the V command, except that each new vertex position is calculated sequentially, instead of simultaneously, and an arbitrary subset of vertices may be specified. Fixed vertices do not move. Examples:
vertex_average vertex[2] vertex_average vertex where id < 10 vertex_average vertex vv where max(vv.facet,color==red) == 1
vertex_merge(integer,integer)Note the syntax is a function taking integer vertex id arguments, not element generators. Example:
vertex_merge(3,12)
wrap_vertex(vexpr,wexpr)In a symmetry group model, transforms the coordinates of vertex number vexpr by symmetry group element wexpr and adjusts wraps of adjacent edges accordingly.
ZOOM integer exprZooms in on vertex whose id is the given integer, with radius the given expr. Same as the 'Z' command, but not interactive.