algorithm - GNU Simulated Annealing -

-

i'm working template program given here:

https://www.gnu.org/software/gsl/manual/html_node/trivial-example.html

the program give compiles , runs perfectly, nice. generalise method find minimum of function arbitrary number of parameters.

some cursory reading suggests metric function (m1) used in diagnostic , printing situations , can more or less ignored. remains define e1 , s1 appropriately. unfortunately knowledge of using pointers , void incomplete, i'm stuck trying upgrade configuration 'xp' array of parameters, rather single double.

in naivete tried moving 

double x =  *((double *) xp);

to 

double x =  (*((double *) xp))[0];

where appropriate, didn't work. i'm sure i'm missing stupid, hints nice! defining own e1 output function take these n parameters , return number.

the underlying algorithm, gsl_siman_solve() link provided, generalized work data type. why ubiquitous xp parameter being cast double pointer before use. should straightforward use struct or array or array of arrays instead of doubles provided callbacks coded properly.

the problem gsl_siman_solve() seems support scalar double step size, initial guess, , 'uniform' value (from gsl_rng_uniform()), need map scalar double values naturally multidimensional quantities. can done, messy , not flexible. in case, mapping done in s1().

this akin mapping digits of decimal number multidimensional space: ones digit represents x axis, tens digit represents y axis, , hundreds digit represents z axis, example. incrementing integer, 1 can walk entire 3d space (0, 0, 0) (9, 9, 9). don't have use integers , powers of 10, , components don't have have same range, there inherent limit in range of each component of packed value. in reverse: taking scalar double , unpacking multiple quantities.

lastly, code double x = (*((double *) xp))[0]; won't work because attempting dereference double array, not pointer double, ok. in other words, it's first * problem.


Comments

Post a Comment

Popular posts from this blog

How to run C# code using mono without Xamarin in Android? -

-
i want create program uses mono runtime run c# code (binary not application). i copied libmono.so unity app , i'm write code using documentation: http://www.mono-project.com/docs/advanced/embedding/ and it's working have problems references can access classes mscorlib.dll , have problems system.reflection.assembly class throwing exception, when print console see: system.missingmethodexception: method not found: 'system.reflection.assembly.op_inequality' can fix it? can use mono runtime in c binary on android? ps. i'm using android tests. edit: found solution loading libraries, need set environment variable mono_path libraries path. but have still problems assembly class. the system.missingmethodexception error have seems .net profile mismatch error, 1 explained here . can use mono runtime in c binary on android? yes, using ndk guess. there alternatives can use instead of rolling own, such xmadevlab .
Read more

c# - SharpSsh Command Execution -

-
Image
i trying create ssh client using c#. using tamir.sharpssh library. having issues sending command , getting appropriate response server. the way have been testing sending on ls command, followed cd.. command, followed ls command again -- see whether or not cd.. command being executed properly. however, there no difference between first ls command , second ls command. not entirely sure doing wrong. perhaps using wrong ssh type. have provided code , output getting. have added output expect. using tamir.sharpssh; namespace sshnetexample { class program { static void main(string[] args) { sshexec ssh = null; try { console.write("-connecting..."); ssh = new sshexec(host, username, password); ssh.connect(); console.writeline("ok ({0}/{1})", ssh.cipher, ssh.mac); console.writeline("server version={0}, client versio...
Read more

python - Specify path of savefig with pylab or matplotlib -

-
i struggling on how find correct way specify save path (or repository) when calling function savefig in matplotlib or pylab. i tried several syntaxes, everytime python console returns : filenotfounderror: [errno 2] no such file or directory: '../mydocs/resource/frames/myimage.png' currently, have written following : pylab.savefig('../mydocs/resource/frames/myimage.png') does know how it? thanks in advance! the tilde operator , variable $home entered strings , therefore not function while saving. have provide either relative path (as did) or provide full path. eg. pylab.savefig("/home/username/desktop/myfig.png") .
Read more