Debugging may be done the old-fashioned way, by putting print
statments in code. Another alternative is to put
subcommand in a script
to let the user explore the state of the surface at a given
point in a script. If you can't or don't want to modify
the script, then you can set breakpoints.
BREAKPOINT scriptname linenumberwhere scriptname is the name of the function or procedure and linenumber is the line number in the file where the breakpoint is to be set. There must be executable code on the line, or you will get an error. linenumber may be an expression.
Breakpoints may be unset individually with
UNSET BREAKPOINT scriptname linenumberor as a group with
When a breakpoint is reached, Evolver will enter into a subcommand prompt,
at which the user may enter any Evolver commands (although some commands,
load would be very unwise).
To exit from the
subcommand prompt, use
Single-stepping: At the debug prompt, there is a special
n. which will continue execution to the next line
(to be precise, until the line number changes).
Stack trace: At the debug prompt, the
a stack trace, showing the sequence of function or procedure calls made to
reach the current spot.
debugcontrols the YACC trace feature. Example:
Enter command: debug YACC debugging was OFF. Now ON. Enter command: print asdf Starting parse Entering state 0 Reading a token: Next token is token COMMAND_START_ () Shifting token COMMAND_START_ () Entering state 2 Reading a token: Next token is token PRINT_ () Reducing stack by rule 2 (line 158), -> @1 Stack now 0 2 Entering state 5 Next token is token PRINT_ () Shifting token PRINT_ () Entering state 180 Reducing stack by rule 454 (line 1555), PRINT_ -> print Stack now 0 2 5 Entering state 308 Reading a token: Next token is token NEWIDENT_ () Shifting token NEWIDENT_ () Entering state 11 Reading a token: Now at end of input. syntax error Shifting token error () Entering state 316 Reducing stack by rule 391 (line 1295), NEWIDENT_ error -> rexpr ERROR 2381: Syntax error: Unexpected new identifier 'asdf'. Input line so far: print asdf
ccommand gives a brief printout of memory usage, including element memory as calculated for the number of existing elements, and total allocated data memory. For example, on Windows:
Enter command: c Vertices: 50 Edges: 144 Facets: 96 Bodies: 1 Facetedges: 288 Element memory: 40280 Total data memory: 302122 bytes.If the
verbosetoggle is on, then more detailed information (which may depend on your system) is printed:
Enter command: verbose Verbose ON. (was off) Enter command: c Vertices: 50 Edges: 144 Facets: 96 Bodies: 1 Facetedges: 288 Element memory: 40280 vertex size: 152 bytes; number allocated: 156 edge size: 80 bytes; number allocated: 244 facet size: 96 bytes; number allocated: 196 body size: 424 bytes; number allocated: 154 facetedge size: 40 bytes; number allocated: 388 quantity size: 360 bytes instance size: 656 bytes blocks in use: 181 memory in use: 360740 blocks free: 16 memory free: 45080 Heap top: 03477000 Heap size: 48.71 MB Physical memory size: 1072680960 bytes Virtual memory top: 7FFE0000 Session: 4 blocks, 11200 bytes Permanent: 77 blocks, 290922 bytes Temporary: 0 blocks, 0 bytes Total data memory: 81 blocks, 302122 bytes.
For gurus only. The memdebug
command causes verbose information to be printed at every memory allocation,
reallocation, or deallocation. Meant for me to use debugging Evolver itself.
If Evolver was compiled with
MEMSTRINGS defined, then the file and line
location of each memory operation is also printed.
It also causes heap checking
to be done on some systems at each memory operation.
estimatetoggle can be used to verify that gradients are being calculated correctly. When on,
estimatewill, for each '
g' step, print the energy change based on the gradient, that is, calculate the inner product of the velocity and energy gradient at each vertex and sum the products, and then also pring the actual energy change during the motion. For small scales, these numbers should be very close, since energy should change nearly linearly over short scales. For example,
Enter command: estimate Estimation ON. (was off) Enter command: m 1e-6 Scale fixed at 1e-006. Enter command: g 2 Estimated energy change: -9.16981132075472e-006 Actual energy change : -9.16979039722321e-006 2. area: 5.99999083020960 energy: 5.99999083020960 scale: 1.00000e-006 Estimated energy change: -9.16972762183562e-006 Actual energy change : -9.16970669440076e-006 1. area: 5.99998166050291 energy: 5.99998166050291 scale: 1.00000e-006However, if volume constraints or quantity constraints are not satisfied, then it may take a few iterations for agreement to be reached:
Enter command: body.target := 2 Enter command: estimate Estimation ON. (was off) Enter command: m 1e-6 Scale fixed at 1e-006. Enter command: g 5 Estimated energy change: -1.20000000000000e-005 Actual energy change : 2.74061897546020 5. area: 8.74061897546020 energy: 8.74061897546020 scale: 1.00000e-006 Estimated energy change: -8.05951562616423e-006 Actual energy change : -0.000107080144722715 4. area: 8.74051189531548 energy: 8.74051189531548 scale: 1.00000e-006 Estimated energy change: -8.05945861736465e-006 Actual energy change : -8.06006082854083e-006 3. area: 8.74050383525465 energy: 8.74050383525465 scale: 1.00000e-006 Estimated energy change: -8.05934708554515e-006 Actual energy change : -8.05931920133673e-006 2. area: 8.74049577593545 energy: 8.74049577593545 scale: 1.00000e-006 Estimated energy change: -8.05923555500071e-006 Actual energy change : -8.05920767277257e-006 1. area: 8.74048771672778 energy: 8.74048771672778 scale: 1.00000e-006 Enter command:
For optimizing scale, when evolution is well behaved, the estimate will be around twice the actual change, since this is the ratio for a perfectly quadratic energy function. Example:
Enter command: estimate Estimation ON. (was off) Enter command: g 5 Estimated energy change: -1.23332147258421 Actual energy change : -0.647118913175537 5. area: 5.35288108682446 energy: 5.35288108682446 scale: 0.233721 Estimated energy change: -0.420072251955455 Actual energy change : -0.203503019926857 4. area: 5.14937806689761 energy: 5.14937806689761 scale: 0.212928 Estimated energy change: -0.219347968060792 Actual energy change : -0.108607336477709 3. area: 5.04077073041990 energy: 5.04077073041990 scale: 0.197501 Estimated energy change: -0.130401658330236 Actual energy change : -0.0647701891524211 2. area: 4.97600054126748 energy: 4.97600054126748 scale: 0.213378 Estimated energy change: -0.0809651401128813 Actual energy change : -0.0401832076359208 1. area: 4.93581733363156 energy: 4.93581733363156 scale: 0.198322 Enter command:
Beware that non-smooth evolution, for example with one-sided
constraints, can invalidate the assumptions behind
Enter command: hessian_quiet off Enter command: eigenprobe 0 Sparse init alloc: 36897 Expanded hashtable size: 73794. Expanded hashtable size: 147588. Sparse entries: 61444 Final hashtable size: 147588 Hash extra probes: 256957 Variables: 12291 Original fill: 61446 Workspace: 8 bytes Passes through main loop: 34 Total_fill: 538907 Total_flops: 7.25226e+007 Eigencounts: 3 <, 0 ==, 12286 >There are some differences in output depending on whether the ysmp toggle is on (using the Yale Sparse Matrix Package) or off (using my home-grown minimal degree algorithm).
For gurus only. Evolver has a feature that permits numerical checking of the correctness of the named-quantity Hessian-calculating routines. The hessian_diff toggle causes Hessians to be calculated with finite differences of gradients rather than the routines in question. There are some limitations on what kinds of surfaces the numerical Hessian works on, primarily it won't work with volume or quantity constraints. But since any quantity can be tested as an energy, that does not affect its main purpose.
Some internal variables for debugging and tweaking of my minimal degree algorithm:
Enter command: g Calculating volgrads. First move, scale 0.1 Diff: 74.4218 Old_diff: 74.4218 Next diff: 5.17892 Diff: 5.17892 Old_diff: 74.4218 Next diff: 0.350987 first move: scale1 0.1 energy1 5.31028806222661 Body target volume actual volume pressure 1 1 0.999964901275881 2.26415094339623 0th move: scale1 0 energy1 6 Body target volume actual volume pressure 1 1 1 2.26415094339623 Doubling scale, scale 0.2 Diff: 284.517 Old_diff: 284.517 Next diff: 38.248 Diff: 38.248 Old_diff: 284.517 Next diff: 4.87311 Diff: 4.87311 Old_diff: 38.248 Next diff: 0.61629 scale2 0.2 energy2 5.11714524527486 Body target volume actual volume pressure 1 1 0.999938371022819 2.26415094339623 Doubling scale, scale 0.4 Diff: 1032.7 Old_diff: 1032.7 Next diff: 261.432 Diff: 261.432 Old_diff: 1032.7 Next diff: 59.494 Diff: 59.494 Old_diff: 261.432 Next diff: 13.1576 Diff: 13.1576 Old_diff: 59.494 Next diff: 2.89075 Diff: 2.89075 Old_diff: 13.1576 Next diff: 0.634175 scale2 0.4 energy2 5.89816432999747 Body target volume actual volume pressure 1 1 0.99993658248485 2.26415094339623 Final scale: 0.20612 Diff: 301.341 Old_diff: 301.341 Next diff: 41.6649 Diff: 41.6649 Old_diff: 301.341 Next diff: 5.45074 Diff: 5.45074 Old_diff: 41.6649 Next diff: 0.707497 1. area: 5.12110729535848 energy: 5.12110729535848 scale: 0.206120 Enter command: